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Hi,
I work in the event/exhibition industry and have a question regarding the electrical supply I need for a forthcoming stand at the NEC. Our stand has a large LED screen wall (max consumption 20amps) and a number of ancillary items such as monitors,lights and coffee machine (consumption 8amps).

The LED wall supplier has requested either a 32amp 3 phase supply OR two 13 amp sockets on separate circuits with B class breakers. When I queried the options I was told that because of screen "leakage" these are the only options which will prevent nuisance tripping.

The cost of these supplies at the NEC are outrageous (3 phase 32 amp is £2500 for a 3 day show). If I have 3 separate single phase supplies (2 for the wall and 1 for everything else it is equally expensive). I am therefore looking for any advice. I wondered if a 3 phase 16 amp would suffice (this is £1000 cheaper)?

Look forward to your suggestions
 
Hi,
I work in the event/exhibition industry and have a question regarding the electrical supply I need for a forthcoming stand at the NEC. Our stand has a large LED screen wall (max consumption 20amps) and a number of ancillary items such as monitors,lights and coffee machine (consumption 8amps).

The LED wall supplier has requested either a 32amp 3 phase supply OR two 13 amp sockets on separate circuits with B class breakers. When I queried the options I was told that because of screen "leakage" these are the only options which will prevent nuisance tripping.

The cost of these supplies at the NEC are outrageous (3 phase 32 amp is £2500 for a 3 day show). If I have 3 separate single phase supplies (2 for the wall and 1 for everything else it is equally expensive). I am therefore looking for any advice. I wondered if a 3 phase 16 amp would suffice (this is £1000 cheaper)?

Look forward to your suggestions


Wouldn't it best to give the LED wall supplier what they've requested?
 
This is what I have done for this event but we have others coming up using the same kit.

Its a possibility that the wall supplier is simply asking for the 32 amp option because this is the commonest available at most venues. I just wondered if anyone out there could confirm that such a large supply is really necessary.
 
As they mention screen leakage I am led to believe this is more to do with high earth currents taking out RCD devices and by the sound of it which the electronics in the LED screens naturally produce, if this is the case then your options are limited to what they request if you don't want repeated tripping issues, without knowing the earth leakage generated or the exact connection options of the screen then its guess work from me, I would want to know exactly where in the circuit are the RCD devices as to whether you can simply request the cheaper option.
 
If it works on two 13A supplies then the 32A supply will be overkill. The most likely reason for requesting 32A TP is that the only/smallest suitable distribution unit they own requires a 32A TP supply and so that's what they ask for.
I suspect that a 16A TP supply which you can then plug a 16A TP to 3x 16A SP distro into will suffice. Obviously you can then plug 16 to 13 adaptors into each socket to get what you want, you just have to be careful about how the RCD protection is provided.
 
Dave, this is exactly my reasoning and I'm going to question the supplier closely when I see him at the first event
 
For anyone who is interested, the event took place no problem and it soon became apparent that I could have run everything off a 16a TP supply split into 3 x 16a SP. I could hire one of these from HSS if I lived in Southern Ireland for about £30 a week but no one in Britain seems to stock, so looking at getting one made for about £300. An expensive lesson learned....
 
We have got a couple of 16A TP to 3x 16A SP in our hire stock, with individual 30mA rcbo per outlet, and I'm sure most stage lighting and event hire companies will also have them.


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That's interesting, all of the distro boxes I've seen for hire online are 32a or 63a TP. Whats your outfit called if I cant find anything closer?
 
That's interesting, all of the distro boxes I've seen for hire online are 32a or 63a TP. Whats your outfit called if I cant find anything closer?

If you only look online then you probably won't find much at all!

Just phone up someone local to you and ask them, most people will at least have a 16A - 32A adaptor and a 32A TP distro
 
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I think a 16 to 32 would be illegal so probably not stocked and I would certainly get pulled by inspection at the NEC. Biggest outfit round here is Stage Electrics and they don't do 16A.
 
If you already have the 16A distros then could you not just get a 16A 3ph to 3*16A 1ph splitter cable to these distros, it would be a lot cheaper.
 
I think a 16 to 32 would be illegal so probably not stocked and I would certainly get pulled by inspection at the NEC. Biggest outfit round here is Stage Electrics and they don't do 16A.

A 16 to 32 is not illegal, and most of us stock all manner of adaptors such as this.
I can set you up something which will take you from a 16A TP up to 400A power locks of you want, or even 13A all the way up to 400A.

Why on earth do you think it would be illegal or not pass an inspection?

I'm amazed that stage defectives weren't able to help you with this!
 
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I thought it would fail an inspection because the system is being upscaled from source (16 to 32 or even 63a) and it could be accidentally overloaded by an untrained or ignorant user.
 
I thought it would fail an inspection because the system is being upscaled from source (16 to 32 or even 63a) and it could be accidentally overloaded by an untrained or ignorant user.

The system is not being 'upscaled' nor is it being exposed to any more potential for overload than if the adaptor was not used.

It will not fail an inspection as there is nothing dangerous, potentially dangerous nor even remotely questionable or unusual about it.
The entire theatre and events industry would be royally screwed if such adaptors were not permitted or safe!

A 16A supply will have overload protection at 16A, regardless of what you plug in to it.

It is adaptors which go the other way without using an appropriate fuse or circuit breaker which are dangerous. For example a commonly found adaptor which is dangerous is the 32A plug with two 16A sockets connected directly to it.

The simple rule is that you can have an adaptor with a socket of a larger rating than the plug, but you cannot have an adaptor with a socket of a smaller rating than the plug without additional fusing.


How on earth are you managing to comply with BS7909 if you don't even understand this basic principle? Or are you another one of those people who ignore BS7909 completely and earn the whole of our industry a bad reputation?
 
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The system is not being 'upscaled' nor is it being exposed to any more potential for overload than if the adaptor was not used.

It will not fail an inspection as there is nothing dangerous, potentially dangerous nor even remotely questionable or unusual about it.
The entire theatre and events industry would be royally screwed if such adaptors were not permitted or safe!

A 16A supply will have overload protection at 16A, regardless of what you plug in to it.

It is adaptors which go the other way without using an appropriate fuse or circuit breaker which are dangerous. For example a commonly found adaptor which is dangerous is the 32A plug with two 16A sockets connected directly to it.

The simple rule is that you can have an adaptor with a socket of a larger rating than the plug, but you cannot have an adaptor with a socket of a smaller rating than the plug without additional fusing.


How on earth are you managing to comply with BS7909 if you don't even understand this basic principle? Or are you another one of those people who ignore BS7909 completely and earn the whole of our industry a bad reputation?

The amount of people who don't even have a grasp of Bs7909 is scary


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