Electricity for the 4-H Scientist Part 13

[Ill.u.s.tration: Figure 3]

Materials You'll Need

Because no two situations are just alike, it will be necessary for you to make your own list of materials.

As a guide, however, here is a list of typical materials, with the quant.i.ties left blank, for you to fill in as your own requirements and measurements dictate.

10-volt transformer --- Door buzzers --- Doorbells --- Weatherproof outdoor type bells --- ft. indoor bell wire --- ft. 2-wire weatherproof telephone twist --- ft. 3-wire weatherproof telephone twist --- lbs. staples (insulated) --- entrance insulators (for attaching weatherproof to buildings and poles)

Because your transformer must be wired into your regular house current, you should have some help on this from an electrician or other qualified person. Also, you should get that person to review your plans and materials list before you place an order.

Install According to Your Plan

With the aid of an electrician or other qualified person, install your transformer, and test it.

You may then go ahead and complete your signal system, checking carefully with your plan, and making sure that your installations are both electrically and mechanically secure.

Test your system in all possible ways that it might be used.

Demonstrations You Can Give

Build a demonstration board incorporating a farm or home layout, with pushb.u.t.tons or other controls and bells and buzzers appropriately located. Show and tell how the system would save time and energy.

Show and tell how some of these work, and their value: power-off alarm, freezer alarm, fire alarm, driveway alarm.

For More Information

Ask your power supplier or your nearest electrical supply house for catalogs or literature on various types of signal systems, or ask a dealer to show you equipment he has in stock.

LESSON NO. B-11

Credit Points 2

FIRST AID FOR ELECTRICAL INJURIES

What would you do if you saw someone who had been hurt by electricity?

Did you know that you could save his life, if you had taken the time to learn and practice a few simple rules of electrical first aid?

First aid training equips you to know what to do and what not to do for the injured until medical help can be obtained. While the main benefits are for you and your family, no one can call himself a good citizen if he fails to help a stranger who has been hurt.

The information given here is only for electrical injuries. Perhaps what you learn will inspire you to take a complete course in first aid.

What to Do

Learn how to prevent electrical accidents, and what to do if an electrical accident occurs.

1. Make an electrical hazard hunt in your home or on your farm. Point out to your parents everything that should be repaired or replaced for safety's sake.

2. Read the first aid suggestions that follow. Learn them.

3. Get to know the six steps that are outlined for mouth-to-mouth rescue breathing. Practice them on your brother, sister, or parents. Teach the entire family how to do it.

Electricity Can Kill

In this day of hundreds of uses of electricity, you should know about electrical dangers. Electrocution can occur from either low voltage (household type) or high voltage currents. Sometimes household voltages are more hazardous because people underestimate the dangers involved.

A fraction of an ampere pa.s.sing through your heart muscles can be fatal.

Your body offers some resistance to the flow of electricity to ground.

If you are standing on wet ground or in water, or if your skin is damp, this resistance is greatly reduced.

Wire cables within walls and cords on appliances are all insulated with a shock proof covering. Continued use, age, or damage may expose a bare wire and create a hazard. The point of exposure need be only a fraction of an inch. Cords are often used and abused. Exposed wires and signs of wear are danger signals.

Always be wary of overhead wires. People have been injured or killed when kite strings, model plane control lines, irrigation pipe, and water well equipment have come in contact with the power supplier's or their own overhead wiring.

Prevent Accidents

Underwriters' Laboratories (UL) have taken steps to see that minimum safety standards are met in the manufacture of electrical equipment.

Look for the UL label when you buy cords or appliances. Never place cords under carpets or furniture, or drape them over a nail. Replace or repair worn cords without delay.

Be especially careful when operating electric devices in the bathroom.

Keep in mind the dangers of a wet floor, grounded metal pipes, and wet skin. Turning on an AC radio while you are taking a bath is asking for real trouble.

There may be shorts in electric devices. Keep your hands dry when using them, and do not touch them along with grounded metal objects. If you ever get a slight shock, sound the danger signal and do something about it.

Think, Then Act

Your first thought in rescuing a victim from an electrical accident should be your own safety. Speed is also important, because a few seconds or minutes may save a life.

The first question you should ask yourself is "Can I quickly turn off the power?" This would be easier to do in the home than outside. In the case of a victim trapped in a bathtub from a radio accidentally knocked into the water, it might mean simply removing the plug from the wall outlet. If a victim is found grasping shorted, permanently installed equipment and cannot let go, the main switch might be used for quick release of the current.

Outdoors, especially with high tension wires, your danger in rescue is much greater. To handle the victim, touch him only with a long dry stick, dry rope, or a long length of dry cloth. Be sure your hands are dry and that you are standing on a dry board. A broom might be a good lever to pry a victim from a high tension wire but never use a green stick containing sap.

First Aid