New power outlets

[lonfire]

hi,

I do various events mainly in buildings that don't have dedicated power for lights/pa.. however there is one venue that I use more than the others that I'm thinking of getting them to install some decent power outlets.. I worked out the other day that if I used all my lights/pa I would be at the limit of a 32amp ring main..

 

the question is what should I have installed? a 32amp ceeform socket? 2x32amp ceeforms? obviously properly wired back to the fuse box.. will be getting a sparky todo it properly..

 

as most of the stuff I do is in pubs and stuff my DMX dimmers and lights all have 13amp plugs on them and don't really want to change them.. as my dimmers are only 4 channels I don't need the full 16amp I could pull off them so leaving them on 13amp plugs aren't a problem in terms of power handling..

 

my initial thoughts would be to have a 32amp ceeform socket installed and have some leads that daisy chain aload of boards with 13amp sockets on them.. would this be an acceptable way of doing it?

 

I'm half tempted to get two ceeforms installed.. one for PA and one for lighting.. although the PA could easily run off the normal sockets in the hall..

 

any thoughts..

 

thanks

chris

[j_b]

Seeing as the cost of running a slightly thicker cable is negligabe - most of the cost to the venue will be getting a guy in for the day to do the install, not the parts - get spare capacity, otherwise you'll regret it later.

 

For example, say you are using a few bars of PARs and a couple of twirlies at the moment. When you upgrade, and get something intelligent, with a discharge lamp in, the current consumption may go up, as these are using energy even when the shutter is closed.

 

From what you say, if you are at the limit of a 32A ring main, get at least 2x32A installed, each of it's own 32A RCBO or similar - a 3 phase if the venue can would be cool too. You'll quickly then get used the the convienience of just having to find one outlet for your power, rather than 13A extensions from all round the hall.

 

Also, not taking PA from a ring main is a good idea, cos when they do a 'special function' involving your PA and 4 tea urns etc, you might find yourself loosing sound.

[Jivemaster]

I do like cee form as each outlet should be a fully rated spur from a dis board. I dont like ring mains as you never know who or what shares your few amps, Urns and fridges are both common.

 

If your venue will consider it a board of four 13a sockets fed by a separate spur may suit you best.

 

remember it's not the connector but the current capacity that you need,

 

Do ask nicely if you want your venue to pay for this as they will have to get approval from their licensing officer, and could end up with a major refit if they try to alter a system that needs an upgrade.

[lonfire]

hi,

cheers for the info guys..

the venue I'm thinking about is a primary school.. I'm hoping they have all the power I need availible as they used to have a big kitchen for when the school did food which is now a big store room.. various big isolator switchs and stuff around the old kitchen, so hopefuly the sparky should be able to hook into that..

 

my real question is how from one 32amp ceeform do I plug in all the stuff.. would I just daisy chain some boards with 32amp ceeforms on, that also have 13amp sockets on around the place? thats the most logical way I think I'd do it.. its not like I've got one big dimmer rack I need to plug in, just smaller 13amp stuff..

 

is there any limit to the number of sockets I can run off one 32amp ceeform.. in terms of physical sockets (legaly)? with extension leads I've always worked on the basis that as long as I don't overload the main socket its plugs into its ok.. but some people insist on saying "oh you can't plug a four way extension into another 4 way extension.. its dangerous" I suppose it would be if they plugged 7 kettles into it!!

 

thanks

chris

[Brian]

my real question is how from one 32amp ceeform do I plug in all the stuff..  would I just daisy chain some boards with 32amp ceeforms on, that also have 13amp sockets on around the place?  thats the most logical way I think I'd do it..  its not like I've got one big dimmer rack I need to plug in, just smaller 13amp stuff..

 

If you are competent you can make up some distribution boards. I'd go for a board with a couple of 32A ceeform sockets and several twin 13A sockets on all fed from a 32A ceeform inlet. Then make some 32A extension leads. All wiring between the sockets must be rated at 32A or greater. You can then place these at convienient points around your rig to reduce the total number of mains cables running over the floor.

 

The big decision is whether you want individual breakers on all the sockets. I personally wouldn't bother. The 32A socket you plug into will be protected at 32A so you'll never be able to draw more than that. With all wiring rated at 32A there is no danger of overload.

 

However, if you were to ever use this elsewhere, you might want to make a 'master' board with a 32A breaker on the main feed. Like that, if you ever use a 32A socket of unknown capacity you'll protect yourself.

 

If you put breakers all over the place you'll never guarantee which one will go in an overload situation anyways.

 

Oh, and make sure the new 32A socket in the old kitchen is protected by an RCD (earth trip).

 

is there any limit to the number of sockets I can run off one 32amp ceeform.. in terms of physical sockets (legaly)?  with extension leads I've always worked on the basis that as long as I don't overload the main socket its plugs into its ok..

 

There is no theoretical limit for temporary installations. In my office here I have a total of 24 13A sockets running of one 13A plug. I need so many due to the high number of wall warts in use. The total load is only around 6A.

 

but some people insist on saying "oh you can't plug a four way extension into another 4 way extension.. its dangerous"  I suppose it would be if they plugged 7 kettles into it!!

 

Whilst not good practice, it's not dangerous from an overload point of view. The whole lot will still be protected by the 13A fuse in the first plug. It's frowned upon because it shows that you really should have more permanent sockets which are safer (no cables to cut/fray/trip over).

What is bad is using multiple 13A adaptors plugged into each other. Some of the early ones weren't fused and so in theory you could get 30A, limited by the ring fuse/breaker, out of the 'lump'.

[lonfire]

hi,

thats just the sort of info I was after cheers.. I'm compentant with electrics and wiring and I also know when I'm out of my depth which is more important (will not touch 3 phase or high current installation work)..

 

the idea of having a master board with a 32amp breaker on it is a good one.. would probably be an idea to have an RCD on it 2.. that way I'm 100% sure everything is protected.. any issues with potentialy having two RCD's in the same circuit? i.e. I could end up with one at the fuse board level and one of my master board.. obviously its over kill and both could trip which would be anoying.. but if I'm somewhere I don't know what the supply is then it would be better to be safe than sorry..

 

as for breakers on each distro board your right its probably not worth it.. I'm protected at the 13amp level by the fuses in the plugs.. and at the 32amp level by the breaker at the fuse box or on the master board..

 

thanks

chris

[Brian]

any issues with potentialy having two RCD's in the same circuit? i.e. I could end up with one at the fuse board level and one of my master board.. obviously its over kill and both could trip which would be anoying.. but if I'm somewhere I don't know what the supply is then it would be better to be safe than sorry..

It's difficult to say which one would trip first but one of them will trip. Better safe than sorry.

[jexjexjex]

This might sound OTT, but is there a 3 phase supply into the building?

 

You can run a lot of kit from 3 x 32Amps, or even from 3 x 16Amps, but your install costs could be higher.

[lonfire]

hi,

not sure.. will probably have to get a sparky to check that.. although I may have a look next time I'm in there.. I do seem to remember seeing a big power switch with a 415v warning on it.. maybe lucky.. its quite likely they had three phase for the ovens and stuff I guess.. I think its all been isolated though..

 

if there is three phase and I get three 32amp supplys out of it what are the rules when working with three phase (not in terms of installation.. I'll get a sparky todo that for me).. but in terms of isolation between phases..etc.

 

is it a case that all equipment that is connected together in some way (either by data or power cables) should be on the same phase to stop the potential of having a mains fault that could give somebody a 415v shock? I suppose the chances of that are pretty slim.. but I guess there must be some regs about it..

 

rgds

chris

[TomLyall]

If you were to go for Brians idea of a 'master board' as aposed to daisy chaining, then, if you had appropriate protection for it you could use 16a from there onwards. Smaller, cheaper, lighter cables and connectors. The chances of you needing to pull more than 16a on any one 'board' when the total draw is 32a is unlikely, IMHO.

 

Of course it would mean that you would have two different sizes of cable to stock.

 

And these from rubber box might be easier... Rubber Box 140's

[lonfire]

hi,

cheers for that.. they do look good.. but I bet they are expensive! as I have the skills to make them I might as well do that.. (saves a bit of cash)..

 

but certainly worth a look!

 

rgds

chris

[Dweeks]

When this is all done, or you get a quote from the sparky, can you let me/us know please?

 

Just for future reference <_<