Wiring a trip on the board

[actvj]

I'm wiring a 50A circuit breaker into the last slot in my CU. The 50A breaker comes with it's own 30ma RCD module attached. Do I have to wire the breaker nearer the supply end of the CU(as has been suggested to me.) The last slot is at the opposite end to the supply and would mean me shuffling all the other breakers along !

thanks guys for any info returned

actvj

 

[ban-all-sheds]

I'm wiring a 50A circuit breaker into the last slot in my CU. The 50A breaker comes with it's own 30ma RCD module attached. Do I have to wire the breaker nearer the supply end of the CU(as has been suggested to me.)

Yes.

The last slot is at the opposite end to the supply and would mean me shuffling all the other breakers along !

Yes.

There might be a Plan B - is there in isolation switch built into the meter, or between the meter and the CU?

 

[actvj]

yes there is an isolator between the meter and the CU. Then the CU has an main on/off switch.

What's the reason for it being nearer the supply end?

 

[ban-all-sheds]

yes there is an isolator between the meter and the CU. Then the CU has an main on/off switch.

Plan B, then, would be to split the tails and install the new MCB in its own separate enclosure.

What's the reason for it being nearer the supply end?

To mimimise the length of busbar through which heavy currents will flow, to reduce heating and voltage-drop.

 

[andy]

yes there is an isolator between the meter and the CU. Then the CU has an main on/off switch.

What's the reason for it being nearer the supply end?

add a mini CU, but you need an isolator before the CU to split the tails, unless you want to do it live (not recommended)