Outdoor cinema - do i need an electrician??

[louis1]

Hi all,

Non-electrician here.

I am setting up an outdoor cinema in an unusual location under a flyover.

The flyover goes over a canal and the cinema will be under the flyover adjacent to the towpath on a large paved area.

The problem is that the site doesn't have leccy.

But the warehouse on the other side of the canal has 415V 32A 3P+N+E outlets.

So - my proposed solution is to rig SWA on to the underside of the flyover, over the canal and on to the cinema site - where it will terminate in a rubber box distro.

Seeing as I'm just running an extension cable - do I need an electrician?

I won't be doing any 'wiring' as such (apart from putting the commando plugs on the end of the SWA).

Then its just a matter of plugging in to the outlets at one end - and the distro at the other.

It will not be permanent - it will be for about a month.

Thanks in advance for your help.

Louis

 

[Andy™]

yes, you need an electrician. google BS7909 for a start.

you cannot put a commando plug on SWA. it needs to be properly terminated into an enclosure. if you really must use SWA, you will need to terminate it into an adaptable box or similar, and use flex to connect to plug.

how do you plan on attaching said cable to flyover? you would need permission from whoever owns it (local council, highways agency etc)

would also be interested in what you insurance co says about your plans. and the council, since you will most likely need some kind of permission from them

 

[Manator]

There are various regulations that will have to be followed, like those for temporary supplies, and maybe construction? You may also need permission from the waterways to pass over the canal, I would consult an electrician, he will be able to instruct you properly having seen the site, and worked out your power requirements.

 

[Andy™]

also, i hope you realise that a simple 32A extension all the way will probably be too small once VD is included. and then there would be Zs issues. even though its 32A, you may well be looking at 10 or 16mm cable. good luck getting that into a 32A plug

it may even be cheaper to hire a genny. and since your under an flyover, i doubt noise from the genny would be a problem

 

[louis1]

All necessary permissions have been sought - so no problem there.

Looks like I will certainly need an electrician to over see the work.

I plan to attach the cable to the soffit of the roadway using a catenary wire. TfL owns the road and we can't drill in to it without doing a full reinforcement survey to avoid drilling in to the rebar.

I am worried about VD though. The cable will be about 60-80m long. Is that too long?

I don't think we will need the full ~18kW - we can save energy by using LED lighting etc - and when the film is playing there isn't need for much other than the projector (1800W/9.7A Max) - and soundsystem (no more than 1000W RMS / 2000W peak).

A generator is obviously our fallback plan - but it is surprisingly quiet under the flyover - the concrete does a good job of muffling the sound of the cars. So a generator isn't ideal.

 

[Manator]

I would say you are correct VD will be a problem,as would the disconnection times, the temporary supply will have to comply with the regulations, and will also come under other regulations because it is a construction site. If you have already applied for a new supply, you could try to get them to install a temp supply, this is normally done when you first apply, but it could still be an option.