testing a sub main.

[russbrown]

Hi could someone help me please. I'm at college doing 2330 level 3. I'm currently doing inspection and testing. I need to know where I find my (r1+r2) on my sub main. Which is powering a double socket and a light. Thanks

 

[malcolmsanford]

The same as every R1 + R2, at the end of the circuit.

Link out the sub main at the supply board and take your readings at the other end

 

[ste77]

what type of cable is the sub-main?

 

[russbrown]

2.5mm twin and earth

 

[telectrix]

can't be much of a sub-main then. is it in a shed or garage? to ger R1+R2, you would link L and E at the main DB, then measure at the sub incomer with the sub main switch off. think malcolm beat me to that by a mile, but i've been grafting, not on a cushy posting. LOL. :nopity:soz., malc. couldn't resist. beer's on me when you gey back to civilisation ( ahhh, just remembered, you live in kent. ). :dots:

 

[russbrown]

No it's not. It's just on a test rig. Cheers for all your help.

 

[SirKit Breaker]

Hi could someone help me please. I'm at college doing 2330 level 3. I'm currently doing inspection and testing. I need to know where I find my (r1+r2) on my sub main. Which is powering a double socket and a light. Thanks

Just for your info mate, as you are in training.

A sub main is exactly the same as any other radial circuit for the purposes of inspection and test, so the test methods are identical.

Where a sub main differs from a radial circuit, is in its application. A circuit which originates at a Consumer unit or similar and goes into the installation to supply lighting, sockets, cookers etc, is known as a radial circuit.

A circuit which originates at a Consumer unit or similar, and then goes to another consumer unit, like house to garage, then this is still wired as a radial circuit, but it is known as a Distribution Circuit (aka sub main).

The two need to be differentiated, because depending on certain things like protective devices, you can have disconnection times that are different on a distribution circuit from a radial circuit.

I will let you find the difference between a ring main, and a ring final circuit for yourself.

Cheers............Howard