Re Power Clusters

I'm very sorry to say that I - for one - can't really understand what you are trying to say.....Your terminology would indicate you're not from the UK?


If you are trying to use one power source to interconnect different floors, perhaps consider a rising bus bar as one idea. 


By power cluster do you mean a distribution board or a switch fuse or similar? 


In the UK RCDs are generally required for all sockets below 32Amps (Single and three phase) 

In the UK 110V sockets are usually supplied by a 110V transformer - sometimes with its own RCD&MCB on the secondry side - depends on set up - as we have a 230/110V conversion requirement with 55V on each phase to earth. (Combined 110V between each side of the supply - usually coloured brown and blue)


Your last question about a 16mm cable - this would usually be enough for lights and sockets but this depends on how many lights and sockets, length of run and anticipated load. Sockets would need RCD protection probably. 


Are you on a construction site? Section 704 I think it is - in the regulations may well apply.


There are so many variables to my reply that it may well make my answers given here meaningless.

Perhaps engage the services of an M&E (mechanical and electrical) consultant or an NICEIC Approved contractor QS or similar.

Here are some power clusters


I imagine that one would simply loop from one to another as a radial circuit, but that's just a guess.

Ah - power clusters - my apologies and thank you for posting the link......That was just about the most useless Reply I've ever posted...........

Yeah when I say Power Cluster I mean a variety of 400v,230v & 110v sockets (ie 32A HO7RN Cable Type Caravan hook-up type sockets for a construction fabrication rig.

Jimmy

Hi Chris,

I've sort of done that loop from one to another but I've worked out that the Welding units in total at anyone time will be in use will be 4 so they generate in total 64kW so i worked out that current calculation for 400v would be in region of 92Amps so I've decided to go for between 25 and 35mm2 Cable when looping between clusters now on looping would you connect to each RCD of the 400v supply of each Power cluster?.Jimmy

Well I never heard of a Power Cluster unitil today. I must admit I`m a simple soul though!

Would it not be a better design to run a separate supply to each cluster? Especially with the welding loads going on? 


I'm willing to ask and learn so......


Is the supply TT anyway?


I have a site where I have quite a few 10 KVa 110V transformers with a TT supply. 300mA S Type 100 Amp three phase main switch to a few 100mA three phase DBs. The sub distribution circuits to each transformer is either 300mA S Type or 100mA protected and the 10KVa transformer has RCD on any power socket outputs. I'm quite sure someone will comment on the effectiveness of RCD on 110V anyway. For the other voltages plug sockets - 230V and 400V obviously the 30mA RCDs are important. 


Is this the set up to a power cluster - where the 30mA RCD for the final sockets is on the power cluster its self? I don't know but are there separation transformers in there and only the secondary side of the transformer gets to be a socket output? 


When looping on - if it'll allow you to loop on - to the second power cluster I'm half sure you'd be relying on whatever RCD is at the origin of the circuits supply - if you needed an RCD. It may well be possible to design out this need for an RCD because it is, effectively a sub distribution circuit and isn't supplying a socket per se - the cluster is more like a DB and that supplies the sockets and hopefully there is RCD protection there?

Continuing with the Power supply being looped to the individual Cluster would you connect the cable to each RCD within the cluster as the cable is looped to the next cluster then the MCB's can be used to hardwire other distributive requirements like the lighting and sockets within the office?.Please advise?Jimmy

I'm not clear what these power cluster have in the way of incoming cable and isolation but I would recommend you think about maintenance and flexibility. Is there a chance that the first will need to be decommissioned and removed before the others etc?

My suggestion would be to have a main isolator on each floor and loop the supply cables between them and run a cable from the isolator to the Power Cluster, Then, if the Power Cluster needs to go, the isolator can be opened and it is safe to remove it.

Also, you could consider a ring main to allow you to supply No. 5 after 1, 2, 3 & 4 have gone without major rewiring.

Hi Harry,

When you say about looping the supply cables between the Power Clusters on the different floors.Would you connect to the RCD of each of the Power clusters when internally cabling up to the different Power Clusters. Just wondering has to connecting to these Power Clusters internally? .Jimmy