Electrical Safety 2: Checking Answers
Fuse
Electrical Safety 2: Checking Answers
Fuse
Melts if too much
current flows
Protects against
overloads and fires.
Does NOT protect
people against shocks
Electrical Safety 2: Checking Answers
Thermal circuit
breaker
Electrical Safety 2: Checking Answers
Thermal circuit
breaker
Switches off if too much
current flows. Works
using a little heater
inside
Electrical Safety 2: Checking Answers
Magnetic circuit
breaker
Electrical Safety 2: Checking Answers
Magnetic circuit
breaker
Switches off if too much
current flows. Works by
a little electromagnet
inside pulling a switch
Electrical Safety 2: Checking Answers
RCD
also called
RCCBs or ELCBs
One brand is
“Power Breaker”
Electrical Safety 2: Checking Answers
RCD
also called
RCCBs or ELCBs
One brand is
“Power Breaker”
Use these with lawn
mowers and anything
else outdoors
Switches off if the Live
current and Neutral
current are not equal
Protects people from
shocks – switches off
before a lethal current
flows through you.
Electrical Safety 2: Checking Answers
Earthing
Electrical Safety 2: Checking Answers
Earthing
Normally this wire does
nothing, but if there’s a
fault the current goes
this way instead of
through me!
If a machine has a
metal case, this wire
connects the case to
the ground
Electrical Safety 2: Checking Answers
Double
insulation
Electrical Safety 2: Checking Answers
Double
insulation
Plastic case, the
machine has no exposed
metal anywhere
Does not need an earth
wire
Electrical Safety 2: Checking Answers
1. When a fuse “blows”, I should fix the fault that
caused it before I put in a new fuse because...
(a) the new fuse will also blow
(b) to remove any danger
2. Circuit breakers are more convenient
than fuses because...
they are easier to reset
3. Three appliances that need earthing:
e.g. fridge, freezer, computer, washing machine...
Two appliances that do not need earthing:
e.g. hairdryer, TV...
End