isolator or not?

[jparker3007]

hi all
went to start a job today, basically someone who thinks there a spark has 1st and 2nd fixed a small office/ kitchen. when i turned up no power was on site all he had done was pulled cables back to mains cupboard, the wirings all wrong but i can sort that out, my problem/ question is im going to be tapping into one of the phases of the 3phase supply via henly blocks, to suplly a single phase db for the office. now is the any reg where i have to fit a 125A isolato before a new meter (after henlys) or will the db isolator be sufficient?

 

[roukel01]

usually when doing this, you install some kind of fused isolator to fuse it down, to say 60amps or whatever the demand is for that installation. Obvously you need to condsider keeping the 3 phase supply as balanced as possible, some kind of load test to determine which phase would be best to tap into.

 

[jparker3007]

load test done all phases pulling around same, it needs a 100a supply so would it still need iso? a

 

[roukel01]

what size are the main fuses?? Pulling 100amp on one phase is a little high, I would consider putting in a 3 phase board in and splitting the installation up across the 3 phases.

 

[jparker3007]

main fuses are 200a

 

[Sintra]

As roukel01 says split load across phases to keep balance.