Safety devices in electricity

Safety devices in electricity

OBJECTIVES

• Define circuit breaker, fuse, earth wire, double insulation, and ground fault circuit interrupters.

  
  

• Describe the function of circuit breaker fuse, earth wire, double insulation and ground fault circuit interrupters.

• Explain how circuit breaker fuse, earth wire, double insulation and ground fault circuit interrupters provide protection to users of electricity.

  
  

• Enumerate ways of safety precaution when using electricity.

  
  

What does this image tells you?

Open Ended

WILL YOU GIVE EXAMPLES OF SAFETY DEVICES USED IN ELECTRICITY.

Safety Devices in Electricity

Every household has an electricity connected in parallel. Because of this, appliances at home may be used independently of the other. Adding more appliances decrease total resistance, but increase the current. Too large current may cause overloading. To prevent overloading, fuses or circuit breakers are inserted in the circuits.

A fuse is usually a thin piece of wire that will melt and break the circuit if there are too large current flows through it. The thicker the wire, the more current is needed to melt it and higher the “rating” of the fuse. The purpose of a fuse is to protect the wiring and the equipment.

A circuit breaker is an electronic circuit that will switch off the current if it is too great. Such a circuit is designed to operate much more quickly than a fuse and so the damage is less because the current is switched off in a much shorter time. Circuit breakers are often used to protect the user if the casing of the equipment becomes live.

The ground-fault circuit interrupter, or GFCI, is a fast-acting circuit breaker designed to shut off electric power in the event of a ground-fault within as little as 1/40 of a second. It works by comparing the amount of current going to and returning from equipment along the circuit conductors.

Double insulation is insulation that consists of both basic insulation and supplementary insulation. Double insulation protects the user of the appliance from an electrical shock by preventing any possibility of the external casing becoming live (the live wire cannot touch the casing even if wires inside become loose), thus eliminating the need for an earth connection.

Earthing or Grounding is a method of giving electricity the most effective way to return to the service panel. The ground wire is an additional path for electrical current to return safely to ground without danger to anyone in the event of short circuit.

Here are some of the safety tips in using electricity:

• Never put fingers or other objects in an outlet.

  
  

• Keep metal objects out of toasters.

  
  

• Never use anything with a cord or plug around water.

  
  

Here are some of the safety tips in using electricity:

• Never pull a plug out by its cord.

• Don't climb on power poles.

• Never fly kites near power lines.

• Stay away from substations and power lines.

Multiple Choice

It is unsafe for you to work with electricity when you are wet or standing in water.  

• True
• False

Multiple Choice

Found in electrical devices and helps to stop too much current from damaging the device

• circuit

• current

• fuse

Multiple Choice

Your body is a conductor of electricity.

• true
• false

Multiple Choice

What's the first thing you should do if someone is shocked electrically?

• Use the fire extinguisher

• Check for breathing and heartbeat

• Turn off the power source

• Remove the person from the power source

Multiple Choice

A double insulated appliance does not need:

• A fuse
• A earth wire
• A neutral wire

Multiple Choice

The fuse in a circuit melts when:

• An appliance isn't earthed
• Too much current flows
• Too much voltage flows

Multiple Choice

Overloading a circuit with too many appliances could cause overheating and fire.

• True

• False