EPC 20 - SELV, PELV & Earth Leakage Protection Flashcards
What is meant by SELV and PELV?
SELV - Electrically separated from earth.
AS/NZS 3000 Clause 1.4.105
PELV — Electrically not Separated from earth
AS/NZS 3000 Clause 1.4.96.
Is it permissible for SELV circuits to be connected to earth? (Give the Wiring Rules Clause Number).
No.
AS/NZS 3000 Clause 7.5.5.
Which clause in the Wiring Rules specifies requirements for installing ELV cables in the same wiring enclosure as low voltage cables?
AS/NZS 3000 Clause 7.5.4 and 3.9.8.3.
Is it permissible to install a standard 230V/240V10A three flat-pin socket outlet to supply a 12V garden light in a domestic installation?
No.
AS/NZS 3000 Clause 7.5.10.
What is the main type of protection provided by a ‘residual current device’ or RCD?
Protection in the case of a phase to earth fault. AS/NZS 3000 Clause 1.4.102
To what value of tripping current are small domestic RCD’s commonly set?
Most RCD’s are set to 30mA (Type Il) AS/NZS 3000 Clause 2.6.3.2.2
What are TWO common installation wiring faults that may cause an RCD to trip?
Crossed neutrals.
Low insulation resistance.
Is an RCD designed to protection against electric shock if a person comes in contact with the active and neutral at the same time?
No
Is it compulsory for final sub-circuits supplying outlets in non-domestic installations such as a workshop to be protected with residual current devices?
(Give the Wiring Rules Clause Number).
See conditions AS/NZS 3000 Clause 2.6.3.2.3.3.
What is the maximum number of circuits that can be protected by one RCD? (Give the Wiring Rules Clause Number).
Three AS/NZS 3000 Clause 2.6.2.4. (b) (i).
What is the minimum number of RCDs which may be installed in a domestic installation according to the Wiring Rules?
Two AS/NZS 3000 Clause 2.6.2.4 (b) (ii).
