Tweet
Wiring of plug circuits
I have in the past, whilst doing compliance inspections and testing, found plug circuits wired with
1,5mm twin & earth protected by a 15 or 16 Amp circuit breaker. Is this legal ?
Not sure if compliant or not, I had a peek at SARS 10142-1.
So let's see what I came up with.
Regulation 6.15.3 (b) states that single-phase circuits that only supply socket-outlets rated at not
more than 16 Amps shall use conductors that are rated at not less than 16 Amps.
The above regulation is crystal clear. The conductors used for plug circuits must have a current
carrying capacity of at least 16 Amps.
Now let's see what the current carrying capacity of 1,5mm twin &
earth is.
This depends on the installation method.
The methods are as follows:
Method 1. Enclosed in an insulating wall,etc.
Method 2. Enclosed in conduit on a wall or ceiling, or in trunking.
Method 3. Clipped direct.
Method 4. On a perforated cable tray or in free air.
Table 6.3(a) on page 103 of the wiring code gives us the following values for 1.5 mm twin & earth.
Method 1. 14 Amps.
Method 2. 16.5 Amps.
Method 3. 19.5 Amps.
Method 4. 22 Amps.
There's the answer.
Method 1 is illegal as the current carrying capacity is less than 16 Amps.
Methods 2, 3 & 4 are legal provided a circuit breaker rated at not more than 16 Amps
is used for the circuit protection.
Conclusion
In flush mount installations where conduits and wiring are in the walls, ( method 1 ) according to SANS
10142, it is not legal to use 1.5mm twin & earth for the wiring of plug circuits, irrespective of the
circuit breaker size, as the current carrying capacity of the conductor is less than 16 Amps in
contravention of Regulation 6.15.3(b)
In surface mount installations, ( methods 2,3 and 4 ) the current carrying capacity is above 16 Amps and it is therefore acceptable to wire plugs with 1,5mm twin & earth provided that a circuit breaker with a rating of no more than 16 Amps is used.
Is the above conclusion correct ?
What sayeth the other toppies ?
I have in the past, whilst doing compliance inspections and testing, found plug circuits wired with
1,5mm twin & earth protected by a 15 or 16 Amp circuit breaker. Is this legal ?
Not sure if compliant or not, I had a peek at SARS 10142-1.
So let's see what I came up with.
Regulation 6.15.3 (b) states that single-phase circuits that only supply socket-outlets rated at not
more than 16 Amps shall use conductors that are rated at not less than 16 Amps.
The above regulation is crystal clear. The conductors used for plug circuits must have a current
carrying capacity of at least 16 Amps.
Now let's see what the current carrying capacity of 1,5mm twin &
earth is.
This depends on the installation method.
The methods are as follows:
Method 1. Enclosed in an insulating wall,etc.
Method 2. Enclosed in conduit on a wall or ceiling, or in trunking.
Method 3. Clipped direct.
Method 4. On a perforated cable tray or in free air.
Table 6.3(a) on page 103 of the wiring code gives us the following values for 1.5 mm twin & earth.
Method 1. 14 Amps.
Method 2. 16.5 Amps.
Method 3. 19.5 Amps.
Method 4. 22 Amps.
There's the answer.
Method 1 is illegal as the current carrying capacity is less than 16 Amps.
Methods 2, 3 & 4 are legal provided a circuit breaker rated at not more than 16 Amps
is used for the circuit protection.
Conclusion
In flush mount installations where conduits and wiring are in the walls, ( method 1 ) according to SANS
10142, it is not legal to use 1.5mm twin & earth for the wiring of plug circuits, irrespective of the
circuit breaker size, as the current carrying capacity of the conductor is less than 16 Amps in
contravention of Regulation 6.15.3(b)
In surface mount installations, ( methods 2,3 and 4 ) the current carrying capacity is above 16 Amps and it is therefore acceptable to wire plugs with 1,5mm twin & earth provided that a circuit breaker with a rating of no more than 16 Amps is used.
Is the above conclusion correct ?
What sayeth the other toppies ?
Comment