16A Socket

[nry]

Hi all

I plan on having a 16A socket installed for my APC Switched Rack PDU (AP7952)
Incase anyone is wondering its basically a huge extension lead where you can turn individual sockets off remotely..
http://www.apc.com/resource/include/techspec_index.cfm?base_sku=ap7952

Please note that I will be getting a qualified electrician out to install this (although I may run the cable for them to keep costs down) just like to do my research first!

At the moment where this is living is a double 13a socket, I am assuming I need to have a new run of cable to the consumer unit with a dedicated MCB to power this unit (distance of cable to run is about 8m)

Also the unit which I will be plugging in has a IEC-320 C20 connector (looks like http://buysg.com/images/APC_AP9877_1.jpg) I was wondering if its more appropriate to change this to a 16A commando plug? The cable coming out the unit is 1.5mm2
A socket and plug are about £5 each at screwfix

As far as I am aware these commando plugs don't have fuses, will the MCB (depending on which one is installed) have any overload protection?

Thanks
Nick

 

[Taylortwocities]

Also the unit which I will be plugging in has a IEC-320 C20 connector (looks like http://buysg.com/images/APC_AP9877_1.jpg)

Cable from consumer unit would be 2.5mm² with a 16amp breaker.
It is a standard A3 radial circuit like that for an immersion heater.
The breaker is there to protect the cable and will limit the current to your commando plug to 16amp.

 

[jamesmcbride]

I didn't think you could have unshuttered outlets in a domestic installation, but I might be wrong.

I seem remember when I was looking to install my air compressor in my garage, I found a standard 16A commando socket couldn't be installed, so ended up going for an FCU - could be another option?

 

[ban-all-sheds]

Please note that I will be getting a qualified electrician out to install this (although I may run the cable for them to keep costs down) just like to do my research first!

This is notifiable work.

If you are going to want the electrician to certify it then you must engage with him now, agree what work you can do, and have him make the design decisions, particularly with reference to the type of socket.

Expecting an electrician to come along and take responsibility for things you have designed and installed based on asking on an internet forum will lead to nothing but bitter disappointment.

Have you really got more than 3kW of kit to power?

 

[Taylortwocities]

I didn't think you could have unshuttered outlets in a domestic installation, but I might be wrong.

You are right. Thats what 553.1.100 says. There's an interesting thread on this already. Note BAS's comments at the end...
//www.diynot.com/forums/electrics/overhead-power-to-19-equipment-rack.333353/

1.5mm² PVC flex is good for 16amp, maybe just hardwire it into a flex outlet = no need for a socket

 

[EFLImpudence]

will the MCB have any overload protection?

That's what they do.


Just because the rating is a maximum of 16A doesn't mean you have to use it all.

Cut off the plug and fit a normal one or connect to an FCU as james has said.

If you need a dedicated circuit for other reasons then do as TTC has said and hard wire it but a commando socket and plug is not necessary or desirable.

 

[plugwash]

Do you actually need the full 16A capacity?
Do you actually need the extra reliability of a dedicated circuit?
Do you have issues with total capacity of your socket circuit?

If the answer to all those questions is no then just put a 13A plug on the damn thing and plug it in.

And if you DO need the full 16A capacity then you also need to think very carefully about cooling arranagements. 3.7KW is a significant ammount of heat.

 

[nry]

Thanks for all the replies. Taught me a few things today!

Do you actually need the full 16A capacity?
See below
Do you actually need the extra reliability of a dedicated circuit? No
Do you have issues with total capacity of your socket circuit? No


In regards to the capacity the equipment in my 19" rack will be as followed (the measured readings are approx. based on some very basic testing with a power meter) I stress tested all computer systems up to 100% CPU load for the readings, so the readings could be higher

APC Switched PDU - assuming this will consume a few watts to power the relays etc
APC 2200VA UPS - consumes about 50w idle, not too sure on charging (this will only be powering essential servers and network gear not the whole rack)
2U server - 500w PSU consumes up to 270w (100% load)
4U server file server - 800w PSU - consumes up to 430w (100% load)
2U server - 480w PSU consumes up to 240w (100% load)
2U Media PC - roughly 80w max
2U Media PC - roughly 80w max
Networking switches - 55w idle
Other appliances (IP KVM, KVM Switch, Router, Raspberry Pi, Wifi) assuming 100w max here
21" Monitor - 70w
Denon AVR 3311 Amplifier - 670w (according to here http://reviews.cnet.com/av-receivers/denon-avr-3311ci/4507-6466_7-34078969.html not tested myself)
Onkyo SR606 Amplifier- 550w (according to some sources, not tested myself)
HDMI Switches - 30w
Xbox 360 - 100w


Possible additions in the near future
Virgin media Tivo boxes - 20w (according to posts here http://community.virginmedia.com/t5/TiVo/TiVo-power-consumption/td-p/1333148)
Power amps - been toying with the idea of having something a little bit more powerful for my speakers, no idea what these would consume

So this is about 2700w, chances of it all being used at the same time? Next to none
I just was planning for the future on this one, as at the moment there is no carpet down so running any required additional cables would be easy
As mentioned above if I add a few power amps into this they could easily consume an additional 500w
Id probably be fine on a 13a plug to be honest!

As for the 100% load on the servers, this happens quite often as I use them for benchmarking work projects etc so are quite heavily used

Once again thanks for the replies everyone! Not my area of expertise at all this, and I am probably just going OTT!

 

[ban-all-sheds]

Power amps - been toying with the idea of having something a little bit more powerful for my speakers, no idea what these would consume

As well as the Denon and Onkyo both going flat out at the same time?

Your neighbours are going to love you...

So this is about 2700w, chances of it all being used at the same time? Next to none

Less than that, I'd say.

Id probably be fine on a 13a plug to be honest!

Yup.

As for the 100% load on the servers, this happens quite often as I use them for benchmarking work projects etc so are quite heavily used

If you can drive servers like that (particularly media PCs and file servers) at 100% CPU utilisation for anything more than occasional peaks then they are nowhere near powerful enough.

 

[Master of None]

You might want to consider some active cooling for the room. 2.7 kw is a lot of heat for 1 room. And you would not want open windows with 1.2kw of amplifiers.

sorry pugwash just noticed your comment.....

 

[nry]

Room already has an extractor fan which shifts a fair amount of air
Not too sure how its going to cope with this much gear and as I said its very rare that everything is going to be powered on at once.

Was inquiring more on doing this properly rather than just assuming I will never go over 13a

As for the comment on 100% CPU, I have them all setup (media PCs included) so they can all run as a cluster for number crunching and stress testing applications

They are absolutely fine how they are and it would max out some top end servers too with some of the scripts I have to run so in that respect. They would just complete it faster... So makes more sense just to abuse the low spec machines for 5-30mins when needed

 

[SimonH2]

I reckon you're looking at around 1.5 to 2kW max - your numbers for the audio kit are waaaay off. The only way you'll be able to have that sort of audio power going is if you are 100% completely stone deaf - or are aspiring to that state. And of course, so are your neighbours.

That should be fine for a 13A plug.

But, be aware of the UPS. If it actually gets used in anger then it will pull considerably more than the load when the power comes back. "Finger in air" says you should allow for an extra 50% of it's rating (say up to 1kW) initially, though this will drop off rapidly (ie within the first few seconds/minutes) as the battery voltage comes back up. I'd be surprised if the battery charging accounted for more than (say) a couple of hundred watts by the end of the first minute.
This short term extra won't blow the fuse, and it shouldn't overheat the plug for the short time it will be going.

 

[ericmark]

Most already been answered the only question is the socket and shutters.

553.1.4 Every socket-outlet for household and similar use shall be of the shuttered type and, for an a.c. installation. shall preferably be of a type complying with BS 1363.

Plugs and socket-outlets (industrial type) 16, 32. 63, 125 BS EN 60309-2 it would seem could fall foul of the regulation however that would mean a caravan supply where it says 708.553.1.8 Each socket-outlet and its enclosure forming part of the caravan pitch electrical supply equipment shall comply with RS EN 60309-2 and meet the degree of protection of at least IP44 in accordance with BS EN 60529 would not comply and they are of course "for household and similar use" i.e. children will be around where they are used.

However these would comply.

I would personally question the distance that any item would need to be inserted into the holes to contact any live parts? Since even without interlocked switch they are IP44 so even without shutters it would comply with:-
412.2.2.1 The electrical equipment being ready for operation. all conductive parts separated from live parts by
basic insulation only shall be contained in an insulating enclosure affording at least the degree of protection IPXXB
or IP2X.

So personally I would fit one to allow some one to plug a caravan in so why not for any other reason. Since as pointed out either LABC or a scheme registered electrician must over see/do the work it's not really your call. But at worst it means a interlocked switched type.

 

[Astra99]

Were the load to be just over 3kW (but under 3.5kW), what would be wrong with using the old-style BS646 15A plug and socket on a 16A radial? I believe they are still widely used in theatre lighting and other situations where a BS1362 fuse would be a PITA. Alternatively perhaps a French Schuko-style socket (prefer that to the German one which is unpolarised) which (allegedly!!) is rated at 16A or a bit over 3.5kW

 

[SimonH2]

Both the 15A and French sockets would have the same considerations - being un-shuttered. So the same drawback as using the industrial plug, but without the benefit of being an industrial plug with an "industrial" attitude to rating and load margins.
Not to mention, the industrial plug is a lot easier to get a decent size cable into.


But the obvious question one might consider is ... would this truly come under the description of "... for household and similar use ..." ? I think there's a strong argument that it wouldn't - I can't see many people fitting a huge blue plug to their iron or toaster