phases

[peteludman]

just want to check about sockets close together on different phases or can you plug things in on different phases?

the problem is that servers have 2 power supplys for backup if the power goes then the ups takes over but i have just installed a 15 kva ups to feed the DB (which i said was not big enough in the begining) 20A per phase , because the phases are on three seperate walls of the server room and on 1 phase drawing 19 A it blew a trip.
so what they have done is run extension leads round to spred the load so each server is fed from 2 phases 400 v

can i just put different phases next to each other if i just lable the trunking?

 

[Mac]

Lenny posted something about this a while back.As long as they are labelled accordingly,it should be fine.

 

[iansparks]

yep, all reachable outlets where the voltages differance is above 230v should be labelled

 

[peteludman]

ok thats what i thaught thanks

 

[wire the world]

is it possible to have a switch that you can use to select a seperate phase. ie you have three phase supply and you can switch between phases if a phase ever goes down????????????

 

[peteludman]

all phases are being used and it would overload if 2 phases were put on to 1 with a switch so not a good idea thanks

 

[johnnyb]

Why have they run 2x supplies to each cabinet, i take it there is a non ups disboard and a ups disboard on the wall.
We use an automatic changeover contactors that have no dip on em as to smoothly carry the supply on, on there respective phases

 

[peteludman]

one of the buildings have that to a db on ups and generator but it dose not help when there is a problem and a trip went the ups and generator cant help then.

but there was a portable ups plugged in and main supply pluged in , but i have made the main supply a ups and so this problem dont happen again the servers are fed from 2 mcbs but they have put a potential 400 v in to the servers

 

[johnnyb]

Pete, we do alot of computer rms for the national lottery and no way would they have 400v in anyone cabinet, + they don,t allow sockets its got to be a 13amp switched spur with flex outlet.
Thats there spec, not ours, if that helps.

 

[peteludman]

thats what i wanted to be told thats the answer i want thanks , because the ups men said a 15 kva ups is ok and they get paid more than stupid sparks like so they know more than me but as soon as i wired it up i proved my point and it tripped out a main 20A breaker.
i said they should have a 30 kva ups at least. i mean it s not hard to think a 24way db it would be ok to give it a max of 20 A per phase.

thanks again johnny b

 

[Yooj]

I seem to remember that when you have sockets on different phases in the same room and they are not labelled, then they must be placed out of reach from each other. I think this transpired into not being able to simultaneously touch the two sockets at the same time. 2.5 metre separation I think was the accepted distance.

Yooj