Power for two data racks

[talksr]

Hi there, I have two large data racks with 2 x 12 plug PDUs installed into the rear of them.

 

I am a little concerned at the way in-which the power has been configured for these racks.

In summary, each rack has one normal power plug coming from the 12 plug PDU. The pair of these plugs have been plugged in to a double white splitter:

 

This then goes to a single plug in the wall:

 

Obviously, the most sensible option right away would be to get another white cable and split both between two plugs.

You will see I have loads of plug points on the wall, so it seems very silly to have it all coming off of one point.

 

Most importantly, the cable is hot to the touch, as this pair of racks have a full 24 plugs plugged into the PDUs.

When ever we have a power cut, the circuit breaker for this set of plugs trips so there is clearly far too much load coming off of the one socket.

Can anyone suggest a more sensible and safe solution?

 

The cable from the PDUs is too short to stretch to the existing high level plug points.

[3s-gtech]

Holy moley. You are probably pulling in excess of 13A through that single socket and plug - fuse blowing isn't always as simple as you'd expect but the whole setup is madness.

 

Where are the UPSs for the racks?

What is the total rating for the PDUs? They may require at least 16A connectors, which will needs to be wired into the ring - what is the ring rated at cabling wise?

 

First things first - get those two split NOW*. This is a potential fire hazard. From there, you need to get this properly wired in and protected, and if you have servers in those racks you need UPSs to be ordered today. Lack of money for them will be irrelevant when a power spike/brownout/cut takes out swathes of hardware.

 

*As in, today. Even a pair of uncoiled extension leads (13A rated) will be better than what you have.

Edited July 12, 2017 by 3s-gtech

[jthompson]

If the white cable is hot, then I think at the very least you should get a second extension lead and have your PDUs going to separate wall sockets.

 

However, you should have an electrician look at it all. All those wall sockets could be on the same breaker, so in the event of a power cut you'll likely still get it tripping. If some sockets are on a different breaker, you could split your PDUs across them and reduce likelihood of tripping.

 

Depending on the equipment you're running in the racks, it might be appropriate to have an electrician install a commando plug style connection for you, with a beefier breaker in the board (which in turn might involve further electrical work elsewhere in the building).

 

I am not an electrician.

[Edu-IT]

That extension lead is 10A?

[MatthewL]

Wow fire waiting to happen there.

 

The extension lead only has a 10A fuse in too. Just because it has 2 sockets it doesn't mean use 2 sockets, you need to add up the AMP plugged in and in this case you will be totally overloading the lot. The PDU's should be plugged into their own sockets, if there isnt any near by you then need some fitting.

 

Just to let you know if you have a fire involving all that, fire investigation will be able to tell extension leads were in use from what is left and your insurance will be null and void. Same goes with coiled extension leads.

[PotNoodleTech]

Christ on a bike that is a fire hazard and whoever wired that should be sacked, or at least shot.

 

You should be using a 32amp input per cab split into a PDU that then provides all your 13amp IEC kettle connectors.

[talksr]

Thanks guys, I have had the electrician down and he has started working on a solution.

 

Just out of interest, does anyone know how many servers an APC 1500VA UPS can take? It has two 'groups' on it, but currently is only running one of our four servers. I am not looking at using this as any way to solve our power problem, just wondering if I could better utilise it.

This is model:

APC Smart-UPS X 1500 Rack/Tower LCD UPS - 1200 Watt

smx1500rmi2unc

Edited July 17, 2017 by talksr

[3s-gtech]

That depends on the servers. In general terms, you can look at the APC calculator UPS Selector - Select your protection needs

 

Very, very generally you can do a W to VA calculation and consider the runtime you want. I tend to find 1VA on the UPS per W (max draw) of the servers works nicely - so that's three 500W servers on one 1500VA APC UPS - which tends to give enough runtime for shutdown etc. I spec 3000VA units - with five/six servers attached they'll run for 40 minutes.

[PotNoodleTech]

As 3gs said it depends on the spec of the servers but as a rile of thumb I would say a maximum of 4 servers on a 1500 the battery life would only be about 15 mins in that configuration, so really you'd want to run about 2 servers per 1500 ups to get at least 30 mins runtime.

 

I way overspec my UPS because I want an hour runtime minimum out of it.

 

Glad to hear the electrician is sorting it.