Computer circuits please help

[Carney68]

Hi I'm new so sorry if in wrong section, I have been asked to wire up a test rig, the customer wants to put power in for a test rig with 40 double sockets to test computers, till systems and kvrs anyone any recommendations on best way of doing it...

 

[telectrix]

i would not be running that lot through 1 RCD! you would need at least 4 separate circuits, the current demand would not be high so maybe 4 16A radials would suffice.

 

[CrazyScozzese]

All at the same time or just a big room with lots of stations?

CPC currents may be an issue. High integrity.

 

[Des 56]

I suspect the design will need to take into account the average quantity of items likely to be under test at one time
As stated high integrity earthing may be required If so ring circuits could be considered

 

[CrazyScozzese]

Tills often are low demand, they are typically touch LCDs, low spec processing, low tech in general, with a few ac/dc adapters, KVMs, etc, prob 40a for all sockets all at one time. To be safe, two rings, high integrity, absolute max 32a per ring, 20 may be OK.

If they are actual PCs, or Raided servers, then 2 x 32a or 3 x 20a, but I would be surprised if they used that. RCBOs are probably a good idea, they WILL trip a single RCD at some point

Fit a current monitor, it will encourage them to power off at night.

Anyhow, get a look at a typical station, ask what a typical sale is, add it up, double it,compare with the number you first thought of, bingo.

A typical low to mid range PC has a 145 to 240w SPSU running at under 50% when up, an LCD screen, add an AC/DCs adp for addons, a double socket is looking at 2 to 3 max. I have seen 300PCs with old CRTs being commissioned in a 6m x 6m classroom by 5 guys, over a few hours, on a single ring shared with another room. The breaker went once, and that was a duff SPSU.

Get the kit out, stick your clamp around a modded lead.

 

[needasparks]

I see test rig was mentioned so thought i would throw this in. Just worth knowing about if its a new area to some.
http://www.hse.gov.uk/pubns/indg354.pdf

 

[Engineer54]

Your right NS, if this client wants things done properly and this area will be a permanent test area, they will need the power supply delivered via an isolation transformer, in a set-up very similar to that required at school science labs, workshops etc....

It's different if we were just talking about supplying several working computer stations, then what's been advised above by others would suffice. But we are talking about ''open back'' work stations were those working on the internal components are at far greater risk of injury to exposed and often live electrical conections etc...

 

[Inteificio]

Someone more experienced than me may want to clarify my point, all those computers with SMP and filters will dump a lot of harmonics on the feeds.

I would significantly derate the cables to take this in to account.

According to my nice little harmonics guide I read earlier today they recommend speccing the N up by a factor of two on the L to be safe.

 

[SW1970]

Someone more experienced than me may want to clarify my point, all those computers with SMP and filters will dump a lot of harmonics on the feeds.

I would significantly derate the cables to take this in to account.

According to my nice little harmonics guide I read earlier today they recommend speccing the N up by a factor of two on the L to be safe.

Can you mention which guide you are using?