Definition of a circuit.

[Derlyn]

In the following photo .......




Socket outlets 1 and 2 are in the garage.

Socket outlets 3, 4 and 5 are in the lounge.

My question is ....... are there 1 or 2 socket outlet circuits ?

[Isetech]

1 circuit breaker, would indicate one circuit.

However, unless the garage is linked to the house and there is open access, ther emight be other challenges to consider.

[Derlyn]

This has always puzzled me and I might be guilty of issuing hundreds of coc's that are in my opinion fauly.

On the attached circuit diagram, I have always considered it to be 2 circuits. 2 lives leaving the db and 2 neutrals returning to the db. In my opinion, the fact that they are fed from 1 circuit breaker is neither here nor there.

On my test reports, the number of plug circuits is quite often not the number of circuit breakers in the db.

I'm trying to establish whether I have been right or wrong.

[Isetech]

When I do an electrical installation I use white heat shrink to mark each circuit (live and neutral) no matter how many wires in the circut breaker (not more than 3 and not larger than 2,5 and all the other rules that apply) all those wires in the circuit breaker are labeled as 1 circuit. What I might do is label 1 a , 1 b , 1 c to make it easier for me to identify if I have to fault find. In most of my installtions there is only one wire per breaker and I certainly wouldnt connect a lounge and garage plug circuit on one breaker, especially if the garage is not attached t the house. Many houses especially in complexes are attached to the house, you would have to be careful if you find one of the through boxes back to back, because of the fire rating.

[Derlyn]

Ok. So what you are saying is that a circuit breaker can only supply 1 circuit irrespective of the number of lives it supplies and neutrals returning. Interesting.
That means I've been wrong all these years.
Wonder what the other toppies say ?

[GCE]

I read it as 2 circuits

When in doubt - read the definitions from SANS 10142-1

When you read the definition 3.11 and 3.14 , in my opinion it is pretty clear that the reference to circuits is the conductor/wire and not the circuit breaker

3.11
circuit
arrangement of conductors (see 3.14) for the purpose of carrying electric
current

3.14
conductor
material that is capable of conducting electric current

[Isetech]

Interesting, this statement would make every single COC I have issued since 1986 incorrect.

I dont agree, but hey thats just my opnion.

The way I see it, if you switch off plug circuit 1 fed from circuit breaker 1, all the plugs connected to that breaker/circuit will be switched off.

Do you identify the circuit breaker as plugs, circuit 1 and 2 ?

If you have 3 wires connected to a plug in the middle of a room and they branch out from there, do they become circuit 3/4/5 ?

I read it as 2 circuits

When in doubt - read the definitions from SANS 10142-1

When you read the definition 3.11 and 3.14 , in my opinion it is pretty clear that the reference to circuits is the conductor/wire and not the circuit breaker

3.11
circuit
arrangement of conductors (see 3.14) for the purpose of carrying electric
current

3.14
conductor
material that is capable of conducting electric current

[Derlyn]

Thanks GCE.
That's been my understanding.
I was taken to task for indicating 6 plug circuits when there were 4 plug breakers so I had to open the DB to show them that 2 circuit breakers each had 2 circuits connected to them, giving one a total of 6.

I also pointed out that the test report indicates the number of circuits and not the number of breakers.

I feel better now knowing that I have been correct all along.

[Isetech]

This is what I enjoy about this forum, having open discussions about stuff like this.

It also proves that just because you do something 500 times or for the past 30 years that it could actually be incorrect

[GCE]

Interesting, this statement would make every single COC I have issued since 1986 incorrect.

I dont agree, but hey thats just my opnion.

The way I see it, if you switch off plug circuit 1 fed from circuit breaker 1, all the plugs connected to that breaker/circuit will be switched off.

Do you identify the circuit breaker as plugs, circuit 1 and 2 ?

If you have 3 wires connected to a plug in the middle of a room and they branch out from there, do they become circuit 3/4/5 ?

If they wanted you to count circuit breakers they would have put down circuit breakers - Instead of putting " count the wires under the circuit breaker " they put down circuits which is defined as a conductor

[GCE]

This is what I enjoy about this forum, having open discussions about stuff like this.

It also proves that just because you do something 500 times or for the past 30 years that it could actually incorrect

Yip I agree - Think we all learn on a daily basis and the forum makes you think and read things differently sometimes vs having a discussion with oneself .
Normally when I have the discussion with myself , I am correct .

I am fortunate that we have strong technical guys and we can bounce things off each other in the morning which helps - Strong personalities as well so they can get heated , but it keeps the balance

[GCE]

This is what I enjoy about this forum, having open discussions about stuff like this.

It also proves that just because you do something 500 times or for the past 30 years that it could actually be incorrect

Just think - Even more incorrectly filled in COC's for you to kick back

[Isetech]

Dont even joke, now you got me thinking.

Just think - Even more incorrectly filled in COC's for you to kick back

[Derlyn]

Sorry I brought it up. 😂😂😂😂

[Isetech]

I have an interesting situation on a site, I have 2 red wires, a black and a green.

One red wire is connected to a 20 amp mcb circuit 9

and the other connected to a 20 amp mcb circuit 10

but there is only one neutral wire.

The way I see it, because there is only 1 neutral it is incorrect because the neutral could end up carrying 40 amps ?

I still have to trace where they go.

Looking at some of the other wires which are brittle and no longer shiny bright copper and its a 3 phase supply, I can see it is going to get interesting.

This is why sometimes sit is chepaer to just strip the old wiring and rewire the building.

The wires (4 reds, 3 blacks and green) leaving the DB for the lights is also another challenge, you switch off either L1 or L2 breaker the lights stay on, if you switch both breakers, the lights go off.