(1, 2) Circuits for socket-outlets, Mixed circuits and fault-finding

Which is the 10A socket-outlet vs 15A socket-outlet? How does a 20A socket-outlet distinguish itself?

15A has bigger earth, 20A would have bigger A+N slots. 10A can fit into all

Minimum general size for socket-outlet circuits? AS3000 C.3.5.1, Table 3.3

2.5mm

In what cases does a socket-outlet not require a switch? AS3000 C.4.4.4.1

a. Single switch controlling 2 adjacent socket-outlets

b. Socket-outlets rated <10A installed for equipment considered not readily accessible (range hood, down lights, exhaust fan etc.)

c. Socket-outlets switched via equipment plug

Identify the phase locations of this 3P+N+E outlet

P1 left P2 top P3 right N down E middle

What is this socket-outlet called and what does it require to be suitable? AS3000 C.3.3.2.8, C.4.4.4.4

“pendant type”, needs support chain or similar to prevent stress on cable terminations from slack being pulled down. Multiphase outlets need cable-independent support chain if neutral not switched

What protection does a socket-outlet circuit need, and what can be used to meet these requirements?

Circuit breaker + RCD connected in series, or RCBO (Residual current circuit breaker w/ overcurrent protection) which does both

What is the maximum residual current of an RCD allowed in general installations vs high-risk (e.g. aged care, wards) installations? AS3000 C.2.6.3.2.2

30mA for general installations, 10mA for high-risk

5 locations additional cable support is needed in disturbance-prone areas? AS3000 C.3.9.3.3.1

a. Wall surface/underside of ceiling or roof

b. Accessible space between floor + ground

c. Ports of ceiling space w/ >.6m height

d. Within 2m of any accessible space

e. Below raised floors

AS3000 requirements for running TPS cables through concealed wall frame? AS3000 3.9.4.2, 3.9.4.4

Must be >50mm from / allow >50mm movement from plasterboard surface, otherwise cables need more protection

What is earth leakage and how does it affect RCDs protecting a circuit?

Most appliances have some earth leakage, when enough connected on single circuit the total (standing) earth leakage current may trip RCD

What is “Coordination between conductors and protective devices - C2.5.3.1”?

I_B ≤ I_N ≤ I_Z means I_B = current circuit’s designed for (max demand) should be lower than I_N = protective device’s working current should be lower than I_Z = conductor’s continuous current capacity.

What is Table C6 and Table C7 for and what page?

Table C6 (p.478) and C7 (p.479) are simplified protective device amperage selection for single-phase and three-phase respectfully

What is Table C9 for and what page?

Guidance on loading of points per final subcircuit (p.483) (contribution of amps to circuit per load)

How to test insulation resistance on socket-outlet? Between what pins, on what setting and what is the ideal reading?

A-E, N-E on meter range 500V should be >1MΩ

How to test for a short circuit on socket-outlet? Between what pins, on what setting and what is the ideal reading?

A-N on meter range 500Ω should be infinity, unless circuit has fixed load current when the return will be resistance of the load

How to test for circuit interconnection on socket outlets? Between what pins, on what setting and what is the ideal reading?

A1-A2, A1-N2, N1-A2, N1-N2 on meter range 500Ω should be infinity

How to test for polarity + neutral-earth transposition on socket outlet? Between what pins, on what setting and what is the ideal reading?

Refer to chart for expected readings; switch on reads resistances of connected resistor. On meter range 500Ω

How to test for earth continuity and fault loop impedance on a 4C+E cable? Between what pins, on what setting and what is the ideal reading?

P1-E should be around 0Ω on meter range 3Ω; depends on circuit protective device rating

How to test for insulation resistance on a 4C+E cable? Between what pins, on what setting and what is the ideal reading?

A/B/C/N - E should be >1MΩ on meter range 500V

How to test for short circuit on a 4C+E cable? Between what pins, on what setting and what is the ideal reading?

Refer to chart for expected readings but all should be infinity; on meter range 500Ω

How to test for circuit interconnection on a 4C+E cable? Between what pins, on what setting and what is the ideal reading?

Refer to chart for expected readings but all should be infinity; on meter range 500Ω

How to test for polarity + neutral-earth transposition on a 4C+E cable? Between what pins, on what setting and what is the ideal reading?

Refer to chart for expected readings; switch on reads resistances of connected resistor. On meter range 500Ω

In 3-phase, what is positive sequence and what is negative sequence?

ABC is positive sequence, ACB is negative sequence

What is a mixed circuit and where is it used?

Final subcircuit with >1 type of equipment (lights, outlets, appliance) connected, used where impractical to run another final subcircuit for said equipment e.g. outdoor shed w/ lights + outlet, pool area w/ lights + pool pump

What situations does AS3000 specify wiring systems be installed to prevent mutual detrimental effects between services

Between different elec. installations, different parts of same elec. installation, parts at different voltage levels, parts supplying different safety services, between elec. and non-elec. installations, between telecomms