What is the name of the current that flows through a body when exposed to a touch voltage due to a fault?
Touch Current
Why is automatic disconnection of supply is required?
To disconnect the supply if touch voltage exceeds 50 V a.c. or 120 V d.c.
The maximum disconnection time for a circuit supplying hand held class 1 equipment is...
0.4 milliseconds
The maximum disconnection time for a circuit supplying 25 amp 3 phase socket outlets is...
0.4 milliseconds
The maximum disconnection time for a circuit supplying a hot water system is...
5 Seconds
The maximum disconnection time for a sub main circuit is...
5 Seconds
A device that is used to detect a person receiving an electric shock (Earth Leakage Current) and then disconnect the supply to prevent harm is called...
Residual Current Device
Another name for a device used to detect earth leakage current is an...
ELCB
(Earth Leakage Circuit Breaker)
What is the sensitivity rating for RCD’s to provide additional protection against electric shock?
30 mA
What is the sensitivity rating for RCD’s that are used in higher risk installations?
(e.g. Bathrooms and kindergartens)
10 mA
What is a disadvantage of using a low setting mA RCD?
Nuisance tripping
The lower the number in the IP rating, the higher the degree of protection.
False
Zone 1 is the area directly above a bath, shower base or pool.
True
The Zone with the lowest number has the highest degree of risk in a damp situation.
True
What is the minimum distance above a sink less than 40L that you can install a socket outlet?
400 millimeters
What is the minimum distance horizontally from a bath that a non IP protected light switch can be installed?
600 millimeters
What is the minimum size of equipotential bond for a pool conductive structure?
4.0mm
In a domestic installation ALL final subcircuits must be provided with RCD protection
True
Electrical equipment permitted to be installed in Zones 1 and 2 shall have at the least what degree of protection?
IPX5 in communal baths/showers
IPX4 in other locations
At what points will the Touch Voltage appear?
c - i
Determine FIVE points where the touch current through the person will flow in the circuit.
a - f
h - e
b - c
c - i
i - h
Determine the path the fault current will flow
a --> b --> c --> e --> f