new sub board

[devlin maguire]

Hi What is the prescibed method of taking power from a three phase, or single for that matter, distribution board to provide power to another I have always used a spare way with a circuit breaker of suffiicient capacity for the whole sub, or go into the supply side of the main switch But I was working on a job where another subby took power from one of the mainswitch bolted terminations, Just barred the end and looped it round the bolt and tightened it up, I made a light hearted comment (He was a big lad) "saves ******* around" he said then " what'd you do if there was no spare ways" So is there a correct method in the regs?
Mac

 

[andekoch]

As far as I know there should be one 'main switch' for an installation, ie a single switch that isolates the entire installation. It also needs to be labled 'main switch'.

That said you therefore need to be on the load side of the current main switch, or use a spare way with a sufficiently sized breaker as you suggest or
fit a separate main switch (fused is the best option) and feed the existing board as well as the new board from the load side of that; fit a henley block on the load side and connect all the boards into that if the terminals are too small in the switch itself.

 

[devlin maguire]

Cheers ande I think feeding new and existing from supply is the neatest way to go
Mac