Combine lighting spurs or new CU?

[dagoof]

I've bought a commercial premises for my workshop that's needing some re-wiring, I'm just looking for thoughts on the best approach.

The unit is in 2 parts (front/back) - power comes off the street at the front where there's a CU for the front, then there's a another mini 63A CU that runs to the back (which has another 8 port CU connected to it). It's the back unit in question, as the workshop will be there and require at least 4x 30A machines, plus a number of other small draw machines.

So obviously the 63A breaker will need up-rated or by-passed. Just now the back unit has around 30x 600mm fluorescent lighting panels across 4 spurs (10, 10, 5 & 5 lights on each). The spark is pushing for me to replace the fluorescents with LED as they could all be put on 1 spur, but that's probably going to be £800+. I know it's all about the load, but would it be a better option/possibility to combine any of the lighting spurs - or install a larger CU? Or both?

 

[deadshort]

Get a second electrician to advise you and quote for the work.

Kind regards,

DS

 

[dagoof]

Thanks DS, I could do that - would be handy to get a rough idea of what the options might be before that stage though.

 

[Adam_151]

I think you are thinking on *partly* the right lines. To change a load of fittings to LED, just so you can combine circuits at the board (something I've always tried to avoid), in order to avoid changing an 8way SPN board is somewhat strange logic. Note however that you may want to consider changing the fittings for other reasons, depending on running hours there might be some substantial energy savings to be had.

Now if your four 30A machines are actually that (as opposed to just having 32A plugs on, because thats what sockets were present in the previous building.....) then theres going to be some further issues, thats an undiverisified load of 120A, now without knowing what the machines are, or how they are used, it would be difficult to guess at what the load after diversity, but suffice to say, a 63A SPN submain is not likely to be sufficent.... and no, you cannot just uprate the fuse, or god forbid bypass it!

If this is let as a commerial space, then chances are that there will be a 3phase supply present (even if its not currently in use / or even if its not even got a 3phase meter attached) - Pics would be usful here - I think someone has an emoticon for this.... If so, then its likely that a new 3phase board and 4c swa to the back would be the order of the day.

You need to ensure that the chaps you are getting down to quote do commericial / industrial work, domestic installers tend to make some funny design decisions when out of that sphere....

 

[ban-all-sheds]

And you should check with the DNO about permission to run those machines.

 

[dagoof]

Thanks Adam - it was used as retail previously, so doesn't have 3ph at the moment. The loads also 30A + 3x ~24A actually (and it isn't a constant draw on that, just warm up).

I do realise there'd be the running cost argument on changing lights to LED but at an £800 differential, I'd imagine it'd be over a decade to break even on that!

 

[ericmark]

Fluorescent is around 95 lumen per watt and LED around 100 lumen per watt so there is no signifiant power saving going to LED, as to stroboscopic effect I really don't know how LED would far, it would depend on the internal driver used.

As to loading it all depends on cables and transformers fitted, I have worked where it would cost a lot to upgrade the DNO transformer and we had to modify how we used the power rather than simply getting more.

 

[SUNRAY]

Fluorescent is around 95 lumen per watt and LED around 100 lumen per watt so there is no signifiant power saving going to LED, as to stroboscopic effect I really don't know how LED would far, it would depend on the internal driver used.

As to loading it all depends on cables and transformers fitted, I have worked where it would cost a lot to upgrade the DNO transformer and we had to modify how we used the power rather than simply getting more.

I have done some work for a electrical/panel building company and they expanded, taking over part of the building next door for greater workshop space. Before moving in they refitted the area, insulating and lining, suspended ceiling etc. All in all a nice job with 16, 20W LED panels in the ceiling grid which works out to about every 4th panel.
It is about 60 sq m, overall about 10x8m, when you walk in it appears dingy and when working half way between light fittings I soon found some deep shadows. worse than that some of the wiring colours became confusing especially some of the 'dusty' colours that seem to be popular in tri rated these days. Even worse problems existed with resistor colour bands. I regularly walked over to the small window to check.
One day one of the fitters started dumping 4 flou panels in the recycling skip which he had just replaced with LED in a customers premises, I quickly stopped him and recycled them into the w/s ceiling in place of LEDs. They are double 18W fittings and initially only 5 working tubes but the difference is phenomenal, the shadows are much less noticeable and the colour problem gone. When you enter the w/s there was this obvious patch of bright light which soon became the 'sought after' spot for all who work there. Last time I was in the building I noticed a few more have been replaced.
The photometer readings didn't show a remarkable increase but the type of light is so so different.

The stroboscopic effect with the fluo's is less noticeable too.

 

[dagoof]

Thanks Sunray, good to get some 'real world' feedback, the fluros are staying!

 

[ban-all-sheds]

when you walk in it appears dingy and when working half way between light fittings I soon found some deep shadows.

Just a mechanical, beam angle problem. Did they not consider or spec that when choosing lights?

worse than that some of the wiring colours became confusing especially some of the 'dusty' colours that seem to be popular in tri rated these days. Even worse problems existed with resistor colour bands. I regularly walked over to the small window to check.

IANAE, but isn't that what the CRI value is supposed to measure? Did they spec lights with a high CRI?

 

[ericmark]

The main advantage with LED tubes is a 5 foot tube is not fixed to 58W if you so wish you can fit a 24W tube, however then lumen drops from 5400 approx with a HF fitting to 2400 lumen, for corridors where it is simply shadow less lighting this may be OK however in the work area it it's OK then whoever set it up in the first place must have got it very wrong.

I fitted one in my kitchen and got away with it, however it is far darker than the 65W it replaced, for me I could simply not get the access to replace the ballast from old 65W to new 58W and LED was easy way out.

 

[dagoof]

It's 600mm units we have and the unit will be used as a printing workshop, so light quality is vital - would appreciate any thoughts on Fluo vs LED in that respect.

 

[ban-all-sheds]

Lighting so that people can operate machines, or so that they can check and adjust the colours of things?

 

[dagoof]

To some extent, both!

 

[ban-all-sheds]

For the latter I'd advise consulting specialists - if you end up printing things where the colours don't look right your business won't last long.