commercial distribution

[lance]

Hi Im new here need some (alot of help) never usually touch commercial stuff but needs must wiring up new build comprising three ground floor retail units and three offices to be fed from four single phase meters tails for these are further than 3 mts away
Question one do I need to run in armoured cable or can i use 25 mm tails as per domestic
Question two the building is a steel framed building although no exposed steel work what do i need to do regarding the earthing not sure what system tt or tncs will need to enquire
Question three the first floor is to comprise of three offices each having one ring circuit and one lighting circuit and one air conditioning unit these three offices to be fed seperatley from a land lords board complete with individual meters can i feed all four boards via henley block or will ineed to feed the three offfice boards via breaker in land lords board
I did say i needed a lot of help not bad for a first post hey!

 

[Mac]

If it's new build,all the mains cable should already be there.Regarding the earthing system you need to look at the incoming supply.If it's commercial it should also be 3 phase.The separate fuse boards,i would take a separate armoured to each DB depending on the location of each DB.

 

[lance]

Thanks for the advice macca its part of my remit to get the mains in do you suggest 16 mm swa for tails any advice about the feeding of the three offices from the land lords board?

 

[bcm_spark]

Id find out the total demand and work out from there what size tails you need.

Is each office having its own meter? If so you wont be able to feed off one henley block. Each meter will supply a DB. Depending on what containment you use the cable feeding the DB's might not have to be SWA. It will more than likely be TNCS unless it is stuck in a field miles from anywhere.

Why can't I get jobs like this!! Do you want a subby to help you out? Good rates.

Also, if you have to get the supply in, get TP-N 100A per phase should be plenty.