Children are the flowers of life. And if we want the flowers to grow beautiful and healthy, we need to take care of them and protect them, preventing any negative impact. It's unbearably painful when the flowers die...
So the company in which I work does not like something to happen to the “flowers”, trying to monitor not only the state of its production facilities, but also the educational component of the population. To this end, for the third year in Yakutka, a program for the prevention of children's electrical injuries has been implemented.
How does this happen? The company has adopted a whole program of events that take place in the spring, closer to summer, because according to statistics, the level of children's electrical injuries increases in summer.
For the events, our press service developed, together with the Pilgrim design studio, various samples of handouts: memo books, lesson schedules, posters.
During the period of the events, a list of schools in Yakutsk is compiled, which are distributed according to areas of responsibility. A group of workers is assigned to each zone, which will have to conduct several lessons on the prevention of children's electrical injuries. This is not amateur performance, tk. the training program is coordinated with the Ministry of Education of the Republic of Sakha (Yakutia).
In general, we got into this program with Olei . The boss called. Set a task. Don't give, don't take, don't eat.
Let's go get a handout, a list of school phone numbers and start getting ready. We were also given a presentation according to which it was necessary to conduct a lesson. Those. everything was already prepared, and we only had to agree on the time of arrival at the school and conduct the lesson itself.
Olya sorts handouts
We arrived and were warmly welcomed. The venue was the assembly hall, with a screen installed on the stage under the projector. When we entered, the students from grades 1 to 8 were already assembled and noisy as much as they could. We went in, took the microphone and ..: “Hello, children!”, - and at once more than a dozen eyes turned their eyes on us. The lesson has begun.
We did not immediately try to bring down on the children the information that everything is bad, but we started from afar - the first question after the greeting was: "Who knows what electricity is?" And now, for sure, even those who came just to sit and did not bother where they brought him, began to look at us with interest. A couple of seconds after the question was asked, one little girl tentatively held out her hand... "Electricity is what makes my laptop work..." she said uncertainly. "Correctly! And who else knows what electricity is? ”, - after this question, there were already much more hands.
Who knows where electricity comes from?
- Well... Electricity comes from wires... - answered one of the children.
- Correctly. Where does the electricity get into the wires?
- ...
- Let me tell you then... Tell me?
- Yes!!!
So we moved on to the next part of our lesson. They told the children, at least in a primitive, but still, we think, cognitive form, how and where electricity is produced. What are the power plants. They explained in a simplified way the principle of their work and features.
What is a hydroelectric power station?
How a hydroelectric power plant works
Then we smoothly switched to the topic that electricity is not only a friend, but also a source of danger to humans. And most importantly, electricity has no color, no taste, no smell- Therefore, you should be careful when near electrical installations. In particular:
You can not play near power facilities;
- you can not climb on the supports of power lines;
- do not touch a hanging or lying electric wire, approach it closer than 8 meters;
- it is impossible to enter the territory of substations, open the doors of electrical installations and electrical panels;
- do not break the insulators, throw foreign objects on the wires;
- you can not fish near power lines;
- you can not make fires under the wires; be near power lines during a thunderstorm;
- do not pull the plug from the socket by the wire;
- do not handle the wire of household electrical appliances with wet hands;
- you can not use faulty electrical appliances and disassemble them when they are turned on;
- you can not approach and touch people who were struck by electric current. If you see a person who was shocked, you must immediately inform one of the adults about him.
We not only said what should not be done, we tried to explain in an accessible way for children why it is impossible to do this, using simple examples, so that there would be no unnecessary questions, and they immediately grasped the essence. It is important.
And yet, communicating with the audience in the form of a dialogue with elements of the game, we tried not only to check, but also to fix the information we told in the minds of the children.
At the very end of the lesson, we distributed posters and reminder books to everyone.
Well, at the very end of the lesson, we showed the children a couple of cartoons on electrical safety, which were made by order of the company.
Apparently, the children liked it, because the teachers had to persuade the children to leave the assembly hall, everyone wanted to come up to us and tell us what he remembered and what he still knows about electrical safety;)
If we talk about the atmosphere, then it is always something new when you work with children - they are always different and positive energy just radiates from them. And this, oddly enough, is the problem. Every time you have to quickly look for something that can attract their attention, some way, some approach that will interest them. If you find a common language with them, they will follow your every action. For example, how to explain to a child that "current" is deadly, despite the fact that not many of them fully understand what death is? It is necessary to give an example, to say that something will be taken away from them, something that is important to them. In our lesson, we said this: “If someone sticks their fingers into the socket, they won’t go for a walk anymore. Never". It was evident from the eyes that this struck many to the core.
Or here's another point. These are children, they love to show off to each other and be the center of attention. Therefore, the most optimal thing is to arrange a talk show with their participation. When asking a question, be sure to approach the child, ask his name and give him the opportunity to speak into the microphone. And at that moment the whole room will look at the one who answers with bated breath. And as soon as the respondent finishes his little speech, tension immediately rises - everyone wants to be in his place. In order not to be boring for children, you need to constantly talk to them. And if you need to explain something, then you can insert a mini-tale into your narrative, about a specific case or an example from life. Children love fairy tales. They remember them best.
If we talk about whether it is difficult to work for a large audience, if there is contact, it is absolutely not difficult.
Well, as a bonus, a couple of pages from the memo book:
Lesson on electrical safety
in 1 B class
"The World of Electricity"
During the classes
I.Organizing time
Introduction by the teacher.
Guys, listen carefully to the riddle and guess it:
I run along the paths
I can't live without paths.
Where am I, guys, no,
The lights won't turn on in the house. ( electricity)
Do you think a person needs electricity? Yes.
What are the benefits of electricity to humans? Refrigerators, washing machines, kettles, computers, TVs, trolleybuses work from electricity.
Doctors, accountants, teachers, installers, trolleybus drivers will not be able to work without electricity. Because many of the appliances that people need are powered by electricity. Without electric current, a dentist will not be able to treat a tooth, a trolley bus driver will not be able to transport passengers, an installer will not be able to grind a part on a machine.
Conclusion:But every person must remember that electric current is needed, but it is not safe for life.
(Knock on the door. Forest animals enter the class: a hare and a fox)
Hare: Oh trouble, oh trouble
Help us friends!
Teacher: What? What happened?
Scene (squirrel ironing ribbons)
Fox: Anyuta the squirrel was stroking the ribbon
And I saw my friends through the window
And I completely forgot about the iron.
Hare: This is no joke!
That's what three minutes means
There is no tape, there is waste all around,
Almost started a fire.
Teacher: Guys, why did the squirrel almost start a fire?
(Answers of children). The squirrel threw the included iron on a ribbon.
Teacher: How to be? How can we be?
How to help the animals?
Teacher: I know one secret.
So that there are no more troubles
We invite all the animals
Hurry up to the lesson.
Pass the forest dwellers, sit down with the guys.
II . Presentation of the topic and objectives of the lesson.
The topic of our lesson is “In the world of electricity”.
Game: "What can be dangerous"
Now we are going to play a game. I will name objects, and if you hear something dangerous, raise your hand.
(electric stove, book, electric socket, soccer ball, washing machine, table, plate, vacuum cleaner, iron)
III. Learning new material a
Today we will talk about electric current, about the rules for using electrical appliances.
Teacher: Guys, what do you know about electric current? Where is he located?
(Children's answers) In the wires of the TV, refrigerator, computer, sockets.
Teacher: Electricity is also “pipes”, only through them energy enters our house. And just as water finds a hole in a pipe and an accident occurs, so does electricity become dangerous if the wires are faulty.
A person can accidentally touch the wire with his bare hand, and he will be shocked. The wires can connect and short circuit (lights go out) or even a fire can occur. Therefore, if you see a bare wire, a faulty switch or socket, you must immediately tell an adult about it!
The history of the emergence of electricity dates back to 550 BC.
For the first time, the phenomena now called electrical were seen in ancient China, India, and later in ancient Greece.
The surviving legends say that the ancient Greek philosopher Thales of Miletus already knew the property of amber, rubbed with fur or wool, attract scraps of paper, fluff and other light bodies.
And you, more than once, I think, have observed that a fountain pen or a comb rubbed on your hair attracts pieces of paper.
Let's do this experience with you. You have pens and small pieces of paper on your desk. They took pens, rubbed them on their hair and brought them to the papers. What are you observing? Yes, papers are attracted to a fountain pen. This phenomenon is called electrification.
But where to our house comes electricity? (children's answers)
Electricity comes through wires.
Teacher: Electricity enters the house through wires, and it comes to the wires from power plants.
The very first power plants were windmills. (slide 2-3)
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Then they began to build solar power plants. (slide 5)
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and nuclear power plants
III.Fizkultminutka.
Tilly - boom! Tilly - boom!
The cat's house is on fire!
The cat's house caught fire
There is a column of smoke!
A chicken runs with a bucket
Fill the cat's house
A horse with a lantern
And a dog with a broomstick.
Once! Once! Once! Once!
And the fire went out!
IV.Continued work on new material.
Teacher: Guys, so that such a disaster as a cat does not happen, what should every person know? (children's answers)
What safety rules with electrical appliances do you know?
(children's answers)
VWorking out the rules for safe handling of electrical appliances
Now we will solve riddles, and explain in what cases things are dangerous.
1. Button on the head,
A sieve in the nose
One hand
Yes, it's on the back. (Kettle.)
- When Is the kettle dangerous?
(When the kettle is turned on,not filling water into it, stick a plug into a faulty outlet, touch a working electric kettle with wet hands; they forget to turn off an ordinary kettle after it has boiledwater, etc.)
2. There is a steamer -
Back, then forward
And behind him such a smooth surface -
Not a wrinkle to be seen Iron.)
In what cases do people risk using this necessary device?
(The electric iron is left on unattended, handled with wet hands, etc.)
3. Masha messed up her jacket.
But I didn't wash it by hand.
There is a special machine -
Washes from the heart to us. (Washing machine.)
Guys, when does this irreplaceable thing for any housewife become dangerous for children? (When it is turned on without parental permission, holding the electric plug with wet hands, opening the lid during operation, etc.)
Well done! And remember: you can not stick your hand into the washing machine during operation, trying to pull something out of it. The hand can tighten and cripple. For most modern models, the hatch is blocked during operation, but if not, be vigilant yourself.
4. That's the house, one window.
Every day in the window - a movie. (Television.)
(Children and teacher discuss the rules for using the TV.)
-Generalization: So, all these things belong to the group of dangerous things - electrical appliances. They pose a threat for two reasons:
First, these items can cause a fire.
Secondly, an electric current passes through them, which can hit.
Teacher: Let's sum up our statements. What are the basic safety rules with electrical appliances?
VI.Working with proverbs about dangerous situations.
No wonder people have put together such proverbs:
"Fear is half salvation"
"Beware of troubles while they are not"
How do you understand the meaning of these proverbs?
(Student answers: you need to be careful, know and follow the rules of safe behavior so as not to get into difficult situations)
VII. Viewing the presentation "Electrical safety rules
at home and on the street »
Presentation. Rules for handling electrical appliances.
1. First rule (slide)
Never enter transformer substations.
THIS IS VERY DANGEROUS FOR LIFE!
2. Second rule (slide)
Do not use electrical appliances in bathrooms, baths, pools and saunas.
3. Third rule
Do not insert the plug into the socket with wet hands.
4. Fourth rule (slide)
 |
Never approach or touch a bare wire. May be electrocuted.
5. Fifth rule (slide)
When pulling out the plug from the socket, never pull the electric wire with your hands, a short circuit may occur.
6. Sixth Rule
Never wipe switched on appliances with a damp cloth.
7. Seventh Rule
Do not extinguish fired electrical appliances with water.
Household appliances at school, at work. Electric current is a true friend and helper of man. And we must treat electricity carefully and carefully. And we have already talked about the dangers of handling electrical appliances.
Student: Everyone knows that iron -
A kind but serious friend.
The one who is familiar with the iron,
Doesn't play with iron.
Student: Who studies science
So appliances does not include:
Overheated outlet
It lights up frequently.
Teacher: Very often, we plug several electrical appliances into the outlet at once. For example: TV, iron, washing machine, refrigerator, computer. And this cannot be done. Because an overheated outlet can also cause a fire or short circuit.
VI.Summing up the lesson.
Teacher: Well done boys! You did a good job in class today. I think our forest guests learned what electric current is and how dangerous it is for life, where electricity comes from in our house, got acquainted with the rules for the safe handling of electrical appliances.
Hare: Oh trouble, oh trouble
Help us friends!
Fox: Anyuta the squirrel was stroking the ribbon
And I saw my friends through the window
Distracted for only three minutes
And I completely forgot about the iron.
Hare: This is no joke!
That's what three minutes means
There is no tape, there is waste all around,
Almost started a fire.
There is a booth in Sasha's yard
There is a drawing on the door.
If you want to be healthy
Don't go into this booth!
Electricity is useful
Electricity is great
But if you climb a pole -
Electricity is dangerous!
If you see - the wire is broken -
Step aside:
Because the electric charge
Dangerous for a child!
Know that the wire is bare
Not a toy at all
Nearly died once
Our neighbor Andryushka!
You can brush your teeth in the bathroom
You can wash your head
Only there we are unlikely to be
Dry hair with a hair dryer.
Student: We would shiver from the cold
It would be dark without him.
Didn't know a lot
Well, of course it would be bad.
Student: TV would not know
Neither eat nor drink
They wouldn't play Dandy either,
In general, it would be bad to live.
Student: Everyone knows that iron -
A kind but serious friend.
The one who is familiar with the iron,
Doesn't play with iron.
Student: Who studies science
So appliances does not include:
Overheated outlet
It lights up frequently.
Electrical safety lesson in elementary school
Target: teach children safe behavior at home
Lesson goals.
Educational : 1. Expand the question: what is electric current
2. Formulate ways to solve the problem of saving electricity.
Developing: 1. To promote the development of students' creative abilities, the ability to work with scientific information, analyze, compare, and express their point of view.
Educational: 1. To form a positive attitude towards the problem of saving energy costs, a sense of responsibility in the operation of electrical appliances.
Tasks : To introduce children to electric current, using it in everyday life;
Teach careful handling of electricity to prevent injury;
Familiarize yourself with the rules of electrical safety;
Cultivate a caring attitude towards electricity;
Equipment: rubber balls, pieces of woolen cloth according to the number of children, posters with electrical safety signs.
Problem: Each of us is a consumer of electricity. Can we contribute to solving the problem? Can electricity consumption be reduced without sacrificing comfort levels? What safety precautions should be observed when using electrical appliances?
Teacher: Hello guys! Today we have an unusual lesson with you, and try to guess what we are going to talk about by listening to the poem.
My grandfather is a big fan of fables.
Tells me about this, about this,
And so that the meaning is always clear,
I myself read about everything.
Long ago it was time
Food was cooked by the fire
As soon as the sun rises,
Lights out - as darkness comes.
But times have changed
And the life of miracles is now full.
Can we turn on the computer
And call a distant city
Catch the waves moving
To treat people in a new way,
Do not heat the stove with firewood,
Surprise with a new fireplace
And warm and feed
What needs to be brightly lit.
After all, electricity is our friend.
But you have to be smart to suddenly.
Didn't turn into an enemy.
To the detriment did not take a step.
The moral of this story is -
The head should work.
And you have to do everything wisely
To not shed tears later.
Teacher:
So, what are we going to talk about today? Presentation #1 (slide #1)
(children's answers ) That's right, about the electric current. Do you know what it is and where does the electric current come from? (children's answers ) and now we will conduct an experiment.
Experience with a balloon and cloth. When you rub objects on a cloth, they receive energy, so they begin to attract lighter objects, rubbing the balls on a woolen cloth, we saw that small, small pieces of paper) objects are attracted to the ball.
This happens because the ball has received energy, in other words, it has become electrified.
There is safe electricity, as in the case of balls dangerous, that goes through the wires.
Please give examples of electrical appliances that a person uses.
(children's answers)
Teacher:
For the first time, the ability of rubbed bodies to attract light objects to themselves was discovered by ancient Greek weavers. They drew attention to the fact that individual parts of the machines made of amber, when rubbed against wool, attracted fluffs, dust particles, straws and other light objects. This property was attributed only to amber. from the name of which the word "electricity" originated, which comes from the Greek word "electron" - amber.
Poem
We are twin sisters
We are called parts.
We come to help you
When we get charged.
We run along thin and thick wires,
And at the right moment we get to you.
Which sisters are you talking about?
What are their names?
And they are called the smallest charged particles. (slide number 2)
Electricity is a stream of tiny charged particles - electrons. Each electron carries a small charge of energy. When these electrons accumulate a lot, an electrical voltage occurs.
How do you think electricity gets into our house?
(children's answers)
Right on the wires. (slide number 3)
Just as water runs through a hose, so electricity enters our home through wires. And it comes to the wires from power plants, and the very first power plants were wind turbines (slide number 4)
What do you think is the importance of electricity for us?
(children's answers)
And tell me, is there a profession in the world that could do without electric current?
Who invented electricity?
(slide number 5)
How did the first light bulb come about?
First, in the ancient era, an oil lamp appeared - a clay or metal teapot with oil, through the spout of which a wick was passed (slide No. 6)
The lamp smoked for many centuries, then in the middle of the 19th century kerosene was obtained from oil, a kerosene lamp appeared (slide number 7)
At the same time, they invented and mastered gas, and gas burners came to our house (slide No. 8)
Now guess the riddles (riddles about the light bulb)
She looks like a pear on the outside,
Whist idle during the day.
And lights up the house at night.
Spent under the ceiling
Amazing lace.
Screwed on the bubble
The fire has lit up!
A pear tree hangs from the ceiling.
And do not think to eat a pear,
Shine like the sun
Drop it - it will break!
Leading:
The lamp will burn for a day
One hundred kilos of coal will burn!
If she shines in vain,
Where is the savings in raw materials?
Who invented the light bulb?
(slide number 9 photo of Thomas Edison)
Guys, what do you think, is it possible to save electricity?
(children's answers)
But as?
(children's answers)
(slide number 10 "Rules of economical and thrifty guys)
(slide number 11)
(slide number 12)
(slide number 13)
(slide number 14)
(slide number 15)
(slide number 16)
(slide number 17)
(slide number 18)
(slide number 19)
TOK comes in
Hello, friends! I'll give you a riddle. and you guess who I am.
On the path I run
I can't do without a path
Where am I guys not-
The lights won't turn on in the house! (children's answers)
CURRENT: That's right, my name is electric current. What do you know about me (children's answers)
TOK: Right guys. Now I will make riddles, and you will guess them. For each correct answer, I will give you a token, the one who collects more tokens will be awarded the title of chief electrician.
*Beware of dust and debris,
I'll deal with you live!
And don't hide in the corners
I’ll still find you there! (slide number 20) (vacuum cleaner)
*This device is ideal
Heats up water instantly.
Just turn it on
Soon we can drink tea! (slide No. 21) (teapot)
* The whole universe lives in it
And the thing is extraordinary (slide number 22) (TV)
*Perform the magic circle
And my friend will hear me! (slide number 23) (phone)
* In the summer, our dad brought
Frost in the white box
And now the frost is gray
Houses in summer and winter.
Protects products
Meat, fish, fruits (slide number 24) (refrigerator)
* to distant villages-cities
Who goes to the cities?
Light Majesty-
It……. (-ELECTRICITY)
CURRENT:
You guys are great! Let's count the tokens earned (winner's ribbon award)
TOK: Now let's play a game. I will name the object, and if it is electric, you sit, and if it is not electric, get up (TV, plate, light bulb, tree, plane, chair. refrigerator. fork. iron, etc.)
TOK: Well done guys! I am sure that you have learned what an electric current is, I can safely leave you and go to other guys! Goodbye!
Host: Electricity helps us a lot. but he demands respect for himself: he wants to be treated as it should be. (presentation No. 2 "Electrical safety rules")
Leading:
Guys. Do not upset your parents with your rash actions! Warn your comrades against dangerous pranks near electrical objects! this will save his life!
Preview:
Technological map of the lesson
Discipline: Labor protection
Group: SP-08
Lesson type: a lesson in learning new material Teacher: Dyachenko E.G.
Type of lesson: Combined lesson
Topic: "Electrical safety during welding"
Stages | Lesson Component | Teacher activity | Student activity | Realization of the goal and objectives |
|
Organizing time 2 minutes | Greetings, the psychological attitude of students to learning activities. | Checking students' readiness for the lesson. | Perception of information | Development of mindfulness, discipline, creating an atmosphere of emotional uplift |
|
Update of reference knowledge 4 min Goal setting and learning objectives | Survey of students using the method of "brainstorming" Reporting the topic, goals and objectives of the lesson | Organizational and controlling; teacher explains AOZU: Task for students: List in the notebook "Sources of electrical hazards in the workplace associated with your future profession" Attitude to gain new knowledge; Statement of the problem by showing a fragment of the cartoon "electrical safety" | Repetition of the previously passed in the production practice Perception of information. | To promote the development of thinking, the ability to analyze, compare and draw conclusions To promote I realize the importance of the acquired knowledge in further professional activity and in life. |
|
Learning new material Control over the primary assimilation of the studied material Homework message. Reflection, summing up | introductory conversation; Lecture with elements of problem presentation Lecture with elements of advanced learning Independent work with the textbook Student presentation "Electric Strike" Frontal conversation. Workshop. Practicing resuscitation actions with a demonstration on the simulator. Performing test work in the form of a test. Mutual control of students Recording homework. Lesson conclusions. Satisfaction with the lesson | conversation Explaining new material, creating problem situations presentation of student speakers Issuing a task Write out - What are electrical injuries. Coordination of work and explanation of difficult moments. Slideshow conversation Demonstration of ventilator and NMS actions Testing instructions. Grading Criteria Explained Brief instruction on homework. Summarizing the results of the lesson and grading. | Perception of information Compose lesson outline Students make presentations on "electrical safety when performing welding work" Performing independent work, students answer questions Student presentation. Perception of information. Outlining of the most important provisions. They answer questions. Outline the main points. Closely monitor the actions of the teacher and remember the order of performing resuscitation. Perform verification work. Check out a friend's work. Write down homework. Listening to homework instructions Answer questions | Development of cognitive interest, activity of thinking. Ability to draw analogies and match. Development of activity of thinking, attentiveness, sociability. Ability to analyze, draw analogies, highlight the main thing. The development of mindfulness. To promote the formation and assimilation of new knowledge among students. The development of attentiveness, a serious attitude to ongoing actions. Awareness of the need for acquired knowledge to save lives in cases of emergency. Application of knowledge to solve the test. The ability to analyze. The development of responsibility. The development of mindfulness, responsibility. The ability to do personal self-assessment. |
Preview:
Topic: Electrical safety in production
Lesson Objectives:
Educational : Introduce students to the main causes of electric shock. The action of electric current on the human body. First aid for electric shock
Developing: Instilling interest in the subject
Nurturing: Rules of conduct for welding work
Type of lesson : Learning new material
Lesson type : Combined, designed for 80 minutes
Equipment: computer, overhead projector
Software:powerpoint program
Lesson structure, methods and time consumption Stages of the lesson Content of the stage Lesson time
Organization Preparing students for the lesson, checking those present at the lesson 0 - 3
Motivation Explanation of the topic, purpose, lesson plan 3 - 6
Actualization of basic knowledge and methods of action Testing students' knowledge on the previous topic (Independent work) 6-20
Formation of new concepts and methods of action Plan for presenting new material 20-50
Consolidation of the acquired knowledge Taking notes of new knowledge with a parallel presentation, students' answers to the teacher's questions, completing assignments, compiling algorithms, etc. 50-75
Summing up the lessons, homework Reporting by the teacher of grades, students recording homework 75-80
Attached to the abstract:
a brief summary of new knowledge;
card with assignments for independent work;
Electronic presentation
Plan for presenting new material:
The main causes of electric shock
The effect of electric current on the human body and types of electrical injuries
First aid for electric shock.
Presentation of new material:
1. The main causes of electric shock
The main causes of electric shock are: exposure to electric current passing in the welding circuit; touching open live parts and wires (accidental, not caused by production necessity, or due to erroneous voltage supply during repairs and inspections); touching current-carrying parts, the insulation of which is damaged; touching current-carrying parts through objects with low insulation resistance; touching the metal parts of the equipment that accidentally become energized (as a result of the absence or damage of protective devices); contact with building parts of structures that accidentally become energized, etc.
Danger, electric shock also creates a variety of equipment: welding current sources, electric drive (including ballasts), electrical equipment for lifting and transport devices, electrified vehicles, high-frequency and lighting installations, electric hand-held machines, etc.
The danger of electric shock is associated with shortcomings in the design and installation of equipment, violations of the rules for its operation, unsatisfactory organization of workplaces, insufficient instruction, etc.
2. The effect of electric current on the human body and types of electrical injuries
The impact of electric current on the human body can cause various electrical injuries (electric burn, skin plating, electric sign and electric shock).
An electric burn can be caused by an electric arc (arc burn) or contact with a live part (current burn) due to the conversion of electric current energy into heat.
Metallization of the skin can occur as a result of mechanical and chemical effects of current, when vaporous or molten metal particles penetrate deep into the skin and the affected area acquires a hard surface.
An electrical sign is a consequence of thermal exposure when a relatively large current flows through a small surface with relatively high resistance at a temperature of 50 - 115 0 C and good contact.
As a result of such a lesion, parched or charred areas of the skin or its swelling appear, as well as an imprint from the touch of the current-carrying part.
An electric shock leads to the excitation of living tissues of the body and is accompanied by involuntary convulsive muscle contractions when an electric current passes through the human body.
Electrophthalmia leads to inflammation of the outer membranes of the eyes, resulting from exposure to a powerful stream of ultraviolet rays from an electric arc. Under the action of an electric current, tissues can be damaged, or it can also act reflexively, that is, damage the nervous system. The reflex effect is expressed very sharply, since when passing through the body, an electric current affects a huge number of sensitive nerves. A very significant effect is exerted by the action of an electric current on the skeletal muscles, causing convulsions, and especially on the heart, causing its fibrillation.
Fibrillation is a condition of the heart when it stops contracting as a whole in a certain sequence, and separate uncoordinated “twitches” of the heart muscle fibers occur; at the same time, the pumping function of the heart ceases and death may occur.
The cause of death, in addition to fibrillation, may be respiratory arrest or burns.
The severity of electric shock to a person depends on a number of factors: body resistance; magnitude, duration of action, type and frequency of current; current paths in the body; state of the body and environmental conditions.
body resistance. The human body, being included in an electrical circuit, is a combination of active and capacitive resistance, the value of which depends on many conditions and consists of the resistance of internal organs and the resistance of the outer integument of the body, mainly the outer layer of the skin.
The resistance of the internal organs is 800 - 1000 ohms and depends on the applied voltage and also on the body temperature.
The magnitude of the current. The current at which the initial sensation of it is fixed is the initial irritating current, and as the initial current increases, the body's reactions intensify (Table 1)
Tab. 1 Sensations arising from the action of an electric current of various sizes
Dangerous for the body is the current at which it is impossible to break away from the conductors on its own, so the breakdown of the skin occurs very quickly, and the magnitude of the current passing through the body increases rapidly.
Alternating current greater than 25-30 mA is a serious danger; a current of more than 50 mA leads to electrical injury and can cause death; a current of 100 mA causes a lethal outcome;
The duration of the current. The duration of current flow through the human body affects the degree of physiological effects and, with a fairly low probability of damaging the current value, has the following values:
With prolonged exposure (up to 30 s), which includes all cases of current flow through the human body when touching parts of the equipment that are energized, the current value should not exceed the threshold value of the releasing current.
Type of current. The effect on the human body of alternating and direct current is different.
For voltages less than 500 V, industrial frequency alternating current is more dangerous than direct current equal to it in voltage. At voltages of about 450 - 500 V, the danger of alternating and direct current is the same. At voltages over 500 V, direct current is more dangerous.
Current frequency. The outcome of electric shock also depends on its frequency (the most dangerous frequency is 50-60 Hz).
In the frequency range 50-:-500 Hz, the danger of alternating current not only does not decrease, but also increases somewhat. With a further increase in the frequency of the current, the danger decreases; at frequencies of hundreds of thousands of hertz, alternating current is not dangerous in relation to electric shock (but the risk of burns remains).
Path of electric current in the body. Essential for the outcome of the impact of the current is its path (“current loop” of the lesion). The longer this path and the closer it is to the vital organs, the more severe the outcome of the lesion.
The most probable current flow paths are: arm - arm, arm - leg, leg - leg.
Body condition. The outcome of the impact of the current is influenced by the individual characteristics of the organism, its physical and mental state. With diseases of the skin, heart, lungs, nervous, etc., the danger of electric shock increases.
A tired person is more susceptible to electric shock, and due to fatigue, the severity of such an electric shock can be aggravated. Experimental data have shown that with intense attention to the expected event, the degree of damage is weakened. The diseased state of the body, alcohol intoxication reduces the resistance of the body and aggravates the effect of the current.
Any heart disease is a contraindication for access to work associated with the danger of electric shock.
External environment. The risk of electric shock may be exacerbated by environmental conditions.
A decrease in atmospheric pressure increases the risk of exposure to electric current and vice versa.
Protective grounding. The vast majority of electrical injuries occurring at construction and installation sites are due to an irresponsible attitude to strict observance of the rules for the operation of electrical networks, devices, tools and lighting, and sometimes outright negligence due to ignorance of the essence of the danger of electric current exposure to a person. In some cases, protective grounding of the welding machine or other electrical equipment is performed using a single ground electrode (Fig. 1). When one of the welding machines or other electrical equipment is shorted to the body, a potential appears on the ground electrode and in all metal parts attached to it on the body of the device and on the surface of the earth around the earth electrode.
Rice. 1. Graph of change in contact voltage with a single ground electrode
1 - the least dangerous case of a person touching grounded equipment; 2- potential curve; 3, - curve characterizing the change in voltage Upr - when changing the distance from the ground electrode; I3 - current passing through the earth electrode; Rz - ground electrode resistance; Upr - touch voltage; h - grounding potential; os - the potential of the base where the person stands
The most dangerous for a worker is touching electrical equipment; which is located at a distance of 20 m from the ground electrode, and the least dangerous - touching the electrical equipment, which is located directly at the ground electrode.
With a single or group ground electrode, a step voltage may occur (Fig. 2) due to the potential difference. The most dangerous is the approach of a single earthing switch operating to the installation site with a large movement step.
When a worker touches two phases simultaneously, the greatest voltage arises in the network and a large current passes through the worker (Fig. 3). When a worker touches one phase, less voltage arises and less current passes through the worker.
When a worker touches a three-phase three-wire network (Fig. 4) with an isolated neutral during the emergency period, i.e. when one of the phases is shorted to ground, the voltage will be much higher than the phase and somewhat less than the line voltage of the network and therefore is the most dangerous.
When a working person touches a phase in a three-phase four-wire network with a grounded neutral during its normal operation, it is more dangerous than touching a phase of a normally operating network with an isolated neutral, but less dangerous than touching an undamaged phase of a network with an isolated neutral during an emergency period (Fig. 5).
Rice. 5. Scheme of a person touching a phase wire of a three-phase four-wire network with a grounded neutral in normal a and emergency b modes
UФ - phase voltage; Ih - current passing through the human body; ro - neutral grounding resistance; r - wire insulation resistance; c is the capacitance of the wire; Rh is the resistance of the human body; rzm - resistance when the phase is shorted to earth; Iz - current passing when the phase is shorted to earth; Io - current passing through the neutral earthing switch
3. First aid for electric shock
It must be remembered that the victim, who is in the current circuit, is himself a conductor of electric current.
Release the victim from the action of the current
Open the circuit with a switch, breaker, plug, remove plugs or turn off the package or circuit breakers on the panel
If there is no shield, socket or other means of disconnecting the electric current, then you need to cut or cut the wires (each wire separately), while the handles of scissors or other cutting tools must be made of insulating material.
If it is impossible to quickly disconnect the victim from the current with the help of tools, you can wear rubber gloves, or wrap your hands in a dry cloth, and put on rubber boots on your feet. Additionally, put a dry insulating object (rug, board) under your feet. You need to pull the victim with one hand, by the edge of the clothes. You can throw the wire away from the victim with a dry stick or board.
First aid depends on the condition of the victim
Immediately lay the victim on his back, horizontally, create an influx of fresh air, give ammonia a sniff, rub and warm the body;
Unbutton clothing that restricts breathing; Check by the movement of the chest whether he is breathing; check for a pulse (on the radial artery at the wrist or on the carotid artery in the neck). A wide fixed pupil indicates a lack of blood circulation to the brain.
Artificial respiration by inhaling air through the mouth or nose
Provide the victim with free passage of air into the lungs through the respiratory tract. The head of the victim is thrown back, for which they put one hand under the neck, and the other is pressed on the forehead. This ensures the departure of the root of the tongue from the back wall of the larynx and the restoration of airway patency. The victim's mouth usually opens. If there is mucus in the mouth, it is wiped with a handkerchief or the edge of a shirt stretched over the index finger. Then they check again if there are any foreign objects in the pipe that must be removed. Then proceed to blowing air into the mouth or nose. When blowing air into the mouth, the assisting person takes a breath, tightly (possibly through gauze or a handkerchief) presses his mouth to the victim’s mouth and blows air into the victim’s mouth with force, simultaneously with his face (cheek) or fingers located on the forehead, pinching the victim nose to ensure that all the inhaled air enters his lungs.
If it is impossible to completely cover the victim's mouth, inhale air into the nose, while tightly closing the victim's mouth.
External (indirect) cardiac massage
Supports blood circulation both in cardiac arrest and in violation of the rhythm of its contractions. The caregiver kneels on the side of the victim and takes such a position as to be able to bend over the victim. Determine the position of the lower third of the sternum. Put on it the base of the palm (cushion) of the unbent brush. The palm of the second hand is placed on top of the first. And they begin to rhythmically press on the lower edge of the sternum. It is necessary to press on the sternum with sharp jerks: in this case, the sternum moves down (towards the back) towards the vertebra by 3–4 cm. The heart is compressed, and blood is squeezed out of its cavities into the blood vessels. Pressing must be repeated approximately 1 time per second. It is desirable that two people trained in the rules of first aid take part in the revival, alternately, every 5-10 minutes replacing each other during artificial respiration and heart massage.
Independent work
Define terms:
Occupational safety is...
safety engineering is...
Industrial sanitation is...
Work safety is...
hazardous production factor is...
harmful factor of production is...
an accident at work is...
the safety of production equipment is ...
process safety is...
Electrical safety during welding
Electrical safety - a system of organizational and technical measures and means to protect people from the harmful and dangerous effects of electric current, electric arc, electromagnetic field and static electricity
Electrical injury - injury caused by exposure to electric current or an electric arc
Electrical injury is a phenomenon characterized by a combination of electrical injuries
Electrical short circuit to the case - an accidental electrical connection of the current-carrying part with its metal knowing parts of the electrical installation
Electrical short to ground - an accidental electrical connection of a current-carrying part directly to the ground or non-current-carrying conductive structures or objects that are not insulated from the ground
The main causes of electric shock are the impact of electric current passing in the welding circuit, contact with open current-carrying parts and wires (accidental, not caused by production necessity, or due to erroneous voltage supply during repairs and inspections); touching current-carrying parts, the insulation of which is damaged, touching current-carrying parts through objects with low insulation resistance, touching metal parts of equipment that accidentally become energized (as a result of the absence or damage of protective devices), contact with building parts of structures that accidentally become energized, and etc
The danger of electric shock is created by welding current sources, electric drive (including ballasts), electrical equipment of lifting and transport devices, electrified vehicles, high-frequency and lighting installations, electric manual machines, etc.
The action of electric current on the human body can cause various electrical injuries (electric burns, skin metallization, electric sign) and electric shock.
Metallization of the skin occurs as a result of mechanical and chemical effects of current, when vaporous or molten metal particles penetrate deep into the skin and the affected area acquires a hard surface.
Electric sign - a consequence of thermal exposure when a relatively large current flows through a small surface with relatively high resistance at a temperature of 50-115 ° C and good contact, resulting in parched or charred skin areas or swelling, as well as an imprint from the touch of the current-carrying part
An electric shock leads to the excitation of living tissues of the body and is accompanied by involuntary convulsive muscle contractions when an electric current passes through the human body.
Electrophthalmia leads to inflammation of the outer membranes of the eyes, resulting from exposure to a powerful stream of ultraviolet rays from an electric arc.
Electric current affects the nervous system. Such an effect is expressed very sharply, since when passing through the body, an electric current affects a huge number of sensory nerves. A significant effect is exerted by the action of an electric current on the skeletal muscles, causing a spasm, and especially on the heart, causing its fibrillation (separate uncoordinated "twitches" of the fibers of the heart muscle) . In this case, the pumping function of the heart stops and death can occur.
The cause of death, in addition to fibrillation, may be respiratory arrest or burns.
The severity of electric shock to a person depends on the following factors, body resistance, magnitude, duration of action, type and frequency of current; current paths in the body, the state of the body and environmental conditions.
Technical means of protection. During the operation of electric welding installations, the use of special protective equipment is required, which are divided into insulating, enclosing and auxiliary
Isolating means of protection are divided into basic and additional.
The main insulating means are able to withstand the operating voltage of the electrical installation for a long time, therefore they are allowed to touch live parts that are energized. Such means include: dielectric rubber gloves, tools with insulated handles and current detectors.
Additional insulating means have insufficient electrical strength and therefore cannot independently protect a person from voltage. These items include: rubber shoes, mats and insulating pads.
Rubber shoes and rugs as additional means of protection are used in operations performed with the help of basic protective equipment.
Enclosing means of protection are intended: for temporary fencing of current-carrying parts (temporary portable fencing-shields, fencing-cages, insulating pads, insulating caps); to prevent erroneous operations (warning posters); for temporary grounding of disconnected current-carrying parts in order to eliminate the danger of electric shock to workers in the event of an accidental voltage appearance (temporary protective grounding).
Auxiliary protective equipment is intended for individual protection of the worker from light, thermal and mechanical influences (goggles, special gloves, etc.).
Protective grounding, grounding and shutdown of electric welding installations and posts. Protective earthing - an intentional electrical connection to earth or its equivalent of metal non-current-carrying parts that may be energized
The purpose of protective grounding is to eliminate the risk of electric shock when voltage appears on the structural parts of electrical equipment, i.e., when shorted to the case.
The scope of protective grounding is three-phase three-wire networks with voltage up to 1000 V with isolated neutral.
There are artificial grounding conductors, intended exclusively for grounding purposes, and natural ones - metal objects located in the ground.
As artificial ground electrodes, vertical and horizontal electrodes are usually used. As vertical electrodes, steel pipes with a diameter of 3-5 cm and angle steel measuring 40X40 to 60x60 mm, 2.5-3m long, steel bars with a diameter of 10-12 mm are used. To connect vertical electrodes and as an independent horizontal electrode, use strip steel with a cross section of not less than 4X12 mm or steel of a round cross section with a diameter of at least 6 mm.
Metal pipes laid in the ground are used as natural grounding conductors, with the exception of pipelines of flammable liquids, flammable or explosive gases, as well as pipelines covered with insulation to protect against corrosion.
Nulling - intentional electrical connection with a zero protective conductor of metal and conductive parts that may be energized (25 2).
Purpose of grounding - similar to the purpose of protective grounding
Zeroing scope - three-phase four-wire networks with voltage up to 1000 V with dead-earthed neutral.
The principle of zeroing operation is the transformation of a breakdown to the case into a single-phase short circuit (i.e., a short circuit between the phase and neutral wires) in order to create a large current that can provide protection and thereby automatically disconnect the damaged installation from the mains. Such protection are; fuses and circuit breakers installed in front of energy consumers for protection against short circuit currents -2 s when defending with machine guns
Protective shutdown - high-speed protection that provides automatic shutdown of the electrical installation in the event of a danger of electric shock in it
The main parts of a residual current device are a residual current device and a circuit breaker
Residual current device - a set of individual elements that respond to a change in any parameter of the electrical network and give a signal to turn off the circuit breaker. Such an element is a sensor - a device that perceives a change in a parameter and converts it into an appropriate signal
Circuit breaker - a device used to turn off and disconnect circuits under load
Providing first aid to the victim from the effects of electric current during welding. First aid in case of accidents from electric shock consists of releasing the victim from the action of the current and providing him with medical care
The release of the victim from the action of the current can be done as follows: turn off the corresponding part of the electrical installation, cut the wires with an ax with a wooden handle or pull the victim away from the current-carrying part, holding his clothes, if it is dry, discard the wire from him with a wooden stick, etc.
If the victim is conscious, but before that he was in a faint or was under current for a long time, he must be provided with complete rest until the arrival of a doctor or urgently taken to a medical facility
In the absence of consciousness, but preserved breathing, it is necessary to lay the victim evenly and comfortably on a soft bedding, unfasten the belt and clothes, provide fresh air, give ammonia to sniff, sprinkle with water, rub and warm the body
In the absence of signs of life, artificial respiration and heart massage should be performed.
Artificial respiration should be started immediately after the victim is released from the current and his condition is identified.
External heart massage aims to artificially maintain blood circulation in the body and restore the independent activity of the heart.
The recovery of heart activity in the victim is judged by the appearance of his own regular pulse, not supported by massage.
Electrical safety requirements for welding equipment
An electric welding installation (a welding transformer, a unit, a converter, a rectifier) must have a passport, an operating manual and an inventory number, under which it is recorded in the log book and periodic inspections.
Transformers, rectifiers and DC generators specially designed for this purpose can be used as welding current sources. Direct power supply of the welding arc from the power (or lighting) distribution shop network is not allowed. Welding-type sources can be connected to distribution networks with a voltage not exceeding 660 V. The load of single-phase welding transformers is evenly distributed between the individual phases of a three-phase network.
In mobile electric welding installations, for connecting them to the network, blocking of the circuit breakers should be provided, which excludes the possibility of connecting and disconnecting the wire when the clamps are energized.
Electric welding installations must be connected to the mains and disconnected from it, as well as repaired only by electricians. Welders are not allowed to perform these operations. The length of the primary circuit between the power point and the mobile welding unit should not exceed 10 m.
The current-carrying parts of the welding circuit must be reliably isolated (insulation resistance must be at least 0.5 MΩ) and protected from mechanical damage. The insulation resistance of electrical circuits of the installation is measured during current repairs in accordance with GOST for operated electric welding equipment. The terms of current and major repairs of welding installations are determined by the person responsible for the electrical facilities of the enterprise, based on local conditions and operating conditions, as well as instructions from the manufacturer. The unit and its starting equipment should be inspected and cleaned at least once a month. All open parts of the welding installation, which is energized by the mains, are securely fenced.
Insulation resistance must be checked at least once every three months, and for automatic submerged arc welding - once a month. The insulation must withstand a voltage of 2 kV for 5 minutes.
Cases of electric welding equipment are zeroed (grounded). For protective grounding (grounding) of the housing, power sources equipped with special bolts are connected to the wire of the grounding (grounding) device. In this case, each welding installation must be directly connected to the grounding (grounding) wire. Serial connection of installations among themselves and the use of a common grounding (grounding) wire for a group of installations is not allowed. Failure to comply with this requirement may lead to the fact that if the wire connecting the installations in series is broken, some of them will turn out to be non-zero.
Electrical safety rules for welding
Before switching on and off the knife switch, you must make sure that its casing is zeroed and that the handle is insulated. If there is damage, the switch is turned off. Before starting work, it is necessary to tidy up the overalls; inspect the workplace, check the serviceability of electric welding equipment, the presence of sealed electrical measuring instruments; wipe dry the floor if it turns out to be slippery (doused with oil, paint, water); check the serviceability of cables, wires and their connection to the nodes of the welding machine. In the presence of malfunctions, electric welding is prohibited. Make sure that your hands, shoes and clothes are always dry.
At the end of welding, the electric welder must turn off the welding transformer or generator, turn off the welding cable with the electric holder, wind the wires into coils and put them in a specially designated place.
Connection and disconnection from the network of electric welding installations, as well as monitoring their good condition must be carried out by electrical personnel with a qualification group of at least III.
What can be used as a return wire for electric welding?
As a return wire connecting the workpiece to be welded to the welding power source, flexible wires can be used, and also, where possible, steel bars of any profile of sufficient cross section. The return wire must be insulated in the same way as the one connected to the electric holder. The use of a grounding network of metal building structures of buildings, communications and non-welding process equipment as a return wire is prohibited.
The individual elements used as a return wire are carefully interconnected (by welding or using bolts, clamps or clamps). In installations for arc welding, if necessary (for example, when making circular welds), it is allowed to connect the return wire to the workpiece to be welded using a sliding contact.
Features of electric welding in especially dangerous conditions
When welding inside metal structures, boilers, tanks, as well as outdoor installations (after rain and snowfall), the welder, in addition to overalls, must additionally use dielectric gloves, galoshes and a rug. When working in closed containers, a rubber helmet must also be worn. The use of metal shields in this case is prohibited.
Work in closed containers is carried out by at least two persons, and one of them must have a qualification group of at least III and be outside the container being welded to control the safe performance of work by the welder. An electric welder working inside the tank is provided with a safety belt with a rope, the end of which must be at the second person outside.
Open-circuit voltage limitation of the welding transformer
All electric welding machines for manual arc welding with alternating current, intended for welding in especially dangerous conditions (for example, inside metal containers, in wells, tunnels, during normal work in rooms with increased danger, etc.), must be equipped with voltage limiting devices idle up to 12 V effective action with a time delay of not more than 1 s
Lesson on electrical safety at school
Introduction
Today it is impossible to imagine human life without electrical energy. Electricity is our faithful assistant at home and at school, at work and at leisure, but it becomes very dangerous for human life if it is not properly handled.
In order not to get into trouble, each of you must remember and follow a few very simple rules, which we will talk about today.
First, let's see what is electricity? Where does it come from? The simplest example of a source of electrical energy is a BATTERY! All of you guys probably have a lot of toys that run on batteries. If such a toy stops working, then the battery that it has inside has run out of charge.
Who knows what needs to be done so that the toy starts working again?
In our life we use a large number of electrical appliances. What electrical appliances can you name?
In order for small toys and appliances (for example, a flashlight) to work, there is enough voltage from the batteries, and in order for large appliances to work - a refrigerator, TV or electric heater - much more electricity is needed. Therefore, each electrical outlet has the same voltage as 150 batteries together! This is a lot!
Electricity is transmitted through wires. All of you children have seen such wires on the street, you have seen that the wires are attached to special high poles and descend from them to each house so that there is such useful ELECTRICITY in each house.
But the fact is that electricity is not only useful, but also VERY dangerous!
In order to use electricity correctly and safely, each person needs to know and follow a few very simple rules.
Electricity on the street. Things to remember and do.
Electricity is supplied to the houses, as a rule, through overhead power lines - the so-called poles with wires attached to them. The poles of overhead lines are specially made so high so that people, even by chance, cannot touch them or come close.
However, due to strong wind or ice, as well as various other damages on overhead lines, the wires can sag or break. If you touch a broken or sagging wire, you will definitely get a strong electric shock! It is very painful and dangerous! Very often, people get burned and even die from touching the wires! So guys, remember the 1st rule:
Do not touch a broken or hanging wire of an overhead line, climb onto supports, trees growing under the wires or buildings next to which electric wires pass!
Do not touch broken or hanging wires
You can't climb on the poles
But not only touching the wire is dangerous. An electric shock can hit and even kill a person who simply APPROVED to a wire that lies on the ground at a distance of less than 8 meters, that is, at a distance equal to ... (visually show a distance of 8 meters using the dimensions of the classroom or other examples).
So guys, remember the 2nd rule:
You must not approach a wire lying on the ground closer than 8 meters, and also do not approach a tree if you notice a broken wire on it!
Now, guys, you and I know that power lines are very dangerous for people, and therefore the wires are suspended on high poles, and from these poles they go down to each house. Where do the wires come from? Where do air lines start?
All overhead lines are connected to transformer substations, in which the voltage is many times greater than the outlet! Of course, such a voltage is even more dangerous for humans, so you need to be able to distinguish transformer substations from other buildings.
Transformer substations may look different. It may be a small brick house, it may be an iron kiosk that looks like a shed, or it may be an iron box standing on poles. In order for someone not to accidentally confuse a very dangerous transformer substation with some other house, special signs are drawn on the doors of substations. For example, these:
These signs warn all people that it is IMPOSSIBLE to go any further! Can electrocute.
This is clearly demonstrated by the drawings drawn by the children of our employees. (You can also organize a children's drawing competition to consolidate the information received).
Of course, IN NO EVENT should you approach transformer substations, play near them, and even more so go inside or climb on them!
And this will be our 3rd rule guys:
(demonstrate drawings No. 4, No. 5 and No. 6 drawn by the children of our employees.)
But what should you do if suddenly one of you sees a wire lying on the ground somewhere? Or will he see a transformer substation with open doors?
In this case, guys, you need to tell adults about everything as soon as possible.
And now let's remember all our rules that we learned today!
Do not touch a broken or hanging wire of an overhead line, climb onto supports or trees growing under the wires!
You can not approach the wire lying on the ground closer than 8 meters!
It is forbidden to enter transformer substations, touch their doors and gratings, arrange games next to them!
If you see a broken or sagging wire, open doors of a transformer substation, or that other children are violating the rules for handling electricity, tell an adult immediately!
