Electrical safety Flashcards
What are the most common electrical safety hazards?
Damadged insulation
Overheating of cables
Damp conditions
How is damadged insulation a safety hazard?
If someone touches and exposed wire, they could be subjected to lethal electric shock
How is overheating of cables a safety hazard?
-Passing too much current through too small of a wire could cause it to overheat
-This could cause a fire, or melt insulation and lead to exposed wires
How is damp conditions a safety hazard?
-If moisture comes in contact with live wires, it could conduct electricity and lead to a short circuit which leads to a fire or an electrocution risk
What are the most common electrical safety devices built into domestic appliances?
-Double insulation
-Insulation
-Earthing
-Fuses
-Circuit breakers
What is insulation?
Covering the wires with an insulating material, such as rubber
What is double insulation?
-An insulation of the wires themselves
-Further insulation in the form of a rubber case around the bundle of wires
-They do not include an earth wire
What is earthing?
A metal case around the electrical appliance
What are potential hazards of earthing?
If a live wire came in contact with the metal cage. the case would be electrified and anyone who touches it would be at risk of electricution. An earth wire can reduce this risk.
What does the earth wire do?
-Provides a low resistance path to the earth
-It causes a surge of current in the wire and hence also in the live wire
-The high current around the fuse causes it to melt and break
-This cuts off supply of electricity to the appliance, making it safe.
What are fuses and circuit breakers?
Electrical safety devices designed to cut off the flow of electricity to an appliance if current gets too large
How does a fuse work?
It contains a metal wire inside a glass cylinder
-If current in the wire gets too large, the wire heats up and melts which then breaks and stops current.
How do circuit breakers work?
-Consists of an automatic electromagnetic switch that breaks circuit if current levels are too high
Why are circuits more commonly used in domestic housing?
-It doesn’t melt and break, thus it can be reused
-It works much faster
