The long and the short of it

[Johnno]

I'm rewiring the spots we use FOH at our school. We've three bars (8 dimmer channels) and two wall brackets (6 dimmer channels). Only the centre bar has built in sockets. The sockets for the rest are just under the ceiling at about 18ft. The bar height is 15ft, similar for the brackets. We've a tower with a platform height of about 11ft.

 

The hall luminaires obstruct the two side bars and the wall brackets, causing massive shadowing on the cyc wall (in the shape of a lady's bosom - complete with nipples - as the luminaires are hemispheres with a pip at the bottom. Lights on the wall brackets get caught by two luminaires so you get a full Jordan :** laughs out loud **: ). To deal with this I'm intending to drop the lights from the bars/brackets on rod and push the shadows up toward the ceiling. This will put the spots further from their sockets meaning longer wires are needed.

 

So, would you choose to rewire the spots with tails long enough to reach any socket (say 2.5m), or with a shorter tail (1m) and then fit a cable connector and use an extension lead which can be left dangling from the socket? If I go with the long wire then there will be a lot of wire coiled up if the light is used on the centre bar or any of the stage bars. The shorter version costs more (about £80).

 

I'm 6ft-odd and can just reach the sockets from the platform. Shorter people would struggle. This is a school. Bit rhetorical this post. :o

[niclights]

I would use extensions, not rewire the fixtures. Re-wiring would be fiddly and require use of silicon flex. If the wiring goes direct to ceramics then you would probably have to splice in with crimp terminals etc.

 

Extensions much simpler, can be linked together or replaced with longer/shorter ones very easily. I am guessing your plugs/sockets are 15A which are a pain to wire and don't the positive lock of a 16A, but still the best option IMO.

 

Make sure you use correct cable for the extensions. I always try to use 2.5mm cores just in case with rubber shell for heat.

 

Avoid coiling any lighting power cables where possible.

[gareth]

But he's rewiring the spots anyway (as explained in the very first sentence of his post), so the question would appear to be not whether or not to rewire, but rather what length of tail should he rewire with?

 

 

I am guessing your plugs/sockets are 15A ... {snip} ... I always try to use 2.5mm cores just in case

There's absolutely no need to use 2.5mm for a 15A cable, unless the run is mahoosively long.

[mumbles]

unless the run is mahoosively long.

Yay, someone else who says mahoosively :** laughs out loud **:

 

Back on topic, 2.5m is a lot of cable to lose when you're just going to a barrel only 30cm's away. I would most definitely go for 1m tails, with another lead to add to it. This then also means that if you hire any lanterns in, you will have a lot of short leads which you would need to reach the socket.

 

The other possibilty to make access less of a headache, would be to have a bar permanently set at the lower height with cabling run between the ceiling and the bar, but I don't know if this would be a feasible option.

[niclights]

So he did. Shouldn't post after (awful) gig!

 

In that case I'm not sure. A lot of extra effort to make extensions as well as the rewire and all the extra components, but as Mumbles says it is a lot of cable to lose when not needed. I guess that's just a re-write of OP and of no use whatsoever. I'll get my coat....

[maeterlinck]

Don't think you mentioned how often the lights move? Where else are they used - % of time in each place? If they spend most of the time on these side bars then longer tails may well be a better option. Otherwise shorter tails makes life easier if they move lots.

Also if you are rewiring everything and not just recabling, then considering 16a connectors might be a good idea, they deal a little better with hanging tension and they are cheaper (see CPC online).

 

HTH

[Don Allen]

With two of the bars having sockets at 18 feet, a platform height of 11 feet and bar height of 15 feet, it seems that you need 1 metre or 3 feet extension leads on most of your outlets including the wall outlets. This will put sockets withing reach of shorter people.

 

Premade leads are cheaper than making your own in a lot of cases so if you could get a bulk lot of 1 metre leads it should solve most areas. The only leads that would be near any hot surfaces would be the side ones.

[si_cole]

I would say keep the fixtures with a short length of lead 1.5 metres or something, and then make up extensions. That way you also have extensions to use at a later date if required.

[Johnno]

Thanks for the suggestions.

 

I'm going to fit 1m tails and use extensions where necessary. I think it would be better if I make it easier to change the lights without having to use the tower at its maximum height. Which might make it easier to get the school management to let my pupil assistants rig lights.

 

I'm joining the cables using IEC320 connectors. This will allow me to use some of the dozens of computer leads lying around here as extensions just by changing their 13A plugs for 5A ones. It would perhaps have been more elegant to use a theatre-industry standard cable connector but I think the expense too great.

[dwh]

There are 16A connectors going cheap on CPC right now I think (something like 69p each, if you get at least 20), have a search for them, more standard, not that expensive...

[Johnno]

There are 16A connectors going cheap on CPC right now I think (something like 69p each, if you get at least 20), have a search for them, more standard, not that expensive...

 

Yes, I've seen those and it costs 0.89 + 1.29 = £2.18 for plug and socket. Prices just checked in their catalogue. Using IECs I get half the connector free.

 

We don't move our lights around much so in the real world it's probably the better decision.

[niclights]

You might want to consider how difficult the IEC's are to wire up. You might regret using them! Personally I would always go for 16A's especially the latest ones which have snap fit terminals and cable grip like XLR's.