Author Topic: Wiring advise for lighting.  (Read 9499 times)

Offline S. Heslop

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Wiring advise for lighting.
« on: March 06, 2015, 07:33:36 AM »
I've recently bought 3 58 watt light battens to try improve lighting in my garage.

I'm a little concerned about overloading the circuit though, so i'm looking for advise on how to not cause a fire.

Here's an awkward diagram of the current situation, with the blue lines representing the existing circuit and the pink lines representing what i'm planning to do. The circle on the left is a junction box.



I've worked out the total wattage of all the lights should be at about 300 watts, but i've found conflicting information online on how much wattage a 1.5mm2 cable can carry, as well as maximum lengths.

It seems like it should be within limits from what i've read though, but i'd feel alot more comfortable if I was certain about it. Any advise is appreciated.

Offline Swarfing

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Re: Wiring advise for lighting.
« Reply #1 on: March 06, 2015, 07:37:11 AM »
It used to be about 1100 watts per lighting circuit but best bet is look up latest regs
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Offline mattinker

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Re: Wiring advise for lighting.
« Reply #2 on: March 06, 2015, 07:59:02 AM »
You have less than 1.5 amps, no problem. Look at the breaker or fuse it's on, you'll be well within it's rating.

Regards, Matthew

Offline vtsteam

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Re: Wiring advise for lighting.
« Reply #3 on: March 06, 2015, 08:51:35 AM »
Simon, only you can see what the circuit to the breaker panel includes besides what you've drawn (if anything).

Are there any additional connections to outlets at present, besides the lighting circuit on this branch? Or is what you've drawn everything on this branch?

Whatever the situation, to calculate this by watts (since that's how you described the light fixtures -- we usually use amperage in the States) check the breaker (or fuse if you guys still have them) for that branch, note the number of amps, multiply by your mains voltage to get totlal watts available before the circuit breaker trips.

Add up the wattage of everything you expect to use on that branch simultaneously, it should be a reasonable amount less than the tripping wattage. Otherwise you'll have the pain in the neck of resetting breakers. That lets you know if you have enough capacity. But doesn't necessarily address the overheating issue.

For that, you need to check your wire size for its rated amperage over the length of the circuit. As an example if a circuit is 100 feet long, and carries a maximum of 15 amps, I would know what size wire I need to carry that (here in the States -- usually by rule of thumb -- but also reflected in the codes). I'm sure there are British equivalents, but I don't know them. You need to find out if you want to do wiring yourself.

If a wire is too thin for the current it has to carry, it will heat up. It will also drop the voltage to a piece of equipment attached to it, and increase its working temperature. the longer the wire, the thicker it needs to be, also. Thicker wire IS more expensive, so generally you don't oversize wiring, but oversizing is a lot better than undersizing.

So knowing all of this, you do your homework, figure out what you have, decide how much more you can add, and what wire size you need, and wire it.

One other cause of electrical fires; poor contacts. Be very sure that when you connect wires to themselves or to terminals, outlets, fixtures, etc. that you use approved methods and tighten properly.

In a loose joint, over time, resistance builds up and creates heat, which makes more resistance, which makes more heat, etc. Then smoke. etc.

As Matt said, it looks like you are adding very little to your circuit with some flourescent fixtures, so very likely to be do-able. But be sure to do the above homework first, to make sure that it isn't already maxed out elsewhere, and be sure to use the right size wire, and make good approved connections.

Then light her up! :thumbup:


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Steve
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Offline John Stevenson

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Re: Wiring advise for lighting.
« Reply #4 on: March 06, 2015, 08:53:45 AM »
Easiest way to improve lighting in there would be to clad the ceiling in plasterboard. Current prices are about £6.20 per 8 x 4 sheet of 9.5mm thick.
Would also improve the situation if you insulated in between but that won't affect the lighting.
John Stevenson

Offline S. Heslop

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Re: Wiring advise for lighting.
« Reply #5 on: March 06, 2015, 09:30:28 AM »
Easiest way to improve lighting in there would be to clad the ceiling in plasterboard. Current prices are about £6.20 per 8 x 4 sheet of 9.5mm thick.
Would also improve the situation if you insulated in between but that won't affect the lighting.

The ceiling is fairly low as it is. I know it wouldn't add much thickness, but I don't like the idea of the lights protruding down on top of that. I've decided to mount the lights inside the gaps between the rafters since, even though it'd reduce the amount of light, it'll hopefully protect them from my dumb ass trying to move boards around.

Thanks for the advise everyone. Yeah I forgot to mention but was meaning to, but the garage is on it's own breaker. I guess i'll get started on getting these lights up then since everything seems to be in order.

Offline buffalow bill

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Re: Wiring advise for lighting.
« Reply #6 on: March 06, 2015, 10:03:27 AM »
Simon
If there isnít a consumer unit in the garage (a garage supply unit)  then I would expect other lighting to be on the same circuit as the garage lights, try lighting the other side of the brick wall or outside lighting.
According to BS7671 current rating for 1.5mm PVC T&E installation reference  method C (clipped direct) is 19.5 amps.
Volt drop for the above is 29mV/amp/meter
The volt drop should be calculated from the supply point to the load, and should be less than 6%
If you do the sums, maxVD  =  13.8 volts, with a load of 2amps max cable run will be  13.8/0.058 x 2 = 119 meters of twin and earth.
 Fluorescent lighting load current = 2 x total wattage/voltage . This is due to the fact that fluorescent lighting is an inductive load. The value of 2 may have reduced since I retired but that was the value I used.
From what you said using 1.5mm cable is suitable for this application, till the cows come home. Take note of VT  advise re connections.
Hope this helps but as JS said plaster board help a lot and a lick of white paint on the walls.
Bill
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Offline DMIOM

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Re: Wiring advise for lighting.
« Reply #7 on: March 06, 2015, 10:14:19 AM »
....... I've decided to mount the lights inside the gaps between the rafters since, even though it'd reduce the amount of light, it'll hopefully protect them from my dumb ass trying to move boards around......

Simon, just a couple of thoughts:

1/ Even if initially its just in those bays where you're popping the lights, I'd freshen the covering with a lick of white paint (pref gloss) including the joists to either side.

2/ I'd suggest using fittings with covers/guards for when the inevitable happens and you swing a board up towards the light

3/ To get started, and possibly to help with compliance, you could always power your array of lights from a 13A plug?

Dave

Offline John Rudd

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Re: Wiring advise for lighting.
« Reply #8 on: March 06, 2015, 10:45:48 AM »
 One thing maybe worth a moments thought.....add an emergency light in case of power cut/ blown fuse/ act of God etc.......just so you can see when the lights go out....??? :zap:
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lordedmond

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Re: Wiring advise for lighting.
« Reply #9 on: March 06, 2015, 12:01:05 PM »
Current capacity is  a wee bit higher than you think

See here

http://www.elecsa.co.uk/Technical-Library/Wiring-Regulations/Inspection-and-Testing/Current-Carrying-Capacity-of-Cables.aspx

Looks to be 20 amp clipped direct  so ok for a 5 amp protected lighting CCT

For lighting you would be ok with 1 mm

Please do not put the lights on a RCD protected circuit machine trips it and you go dark
You can get at a price emergency tube fittings , but a small rechargeable torch that fits into a charging station will do the job

Stuart

Stuart

Offline Arbalist

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Re: Wiring advise for lighting.
« Reply #10 on: March 06, 2015, 12:04:26 PM »
Painting the walls white can also make a huge difference to light levels. All the walls in my workshop are slightly off white and the floor is painted light green.

Offline Pete W.

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Re: Wiring advise for lighting.
« Reply #11 on: March 06, 2015, 12:16:08 PM »
Hi there, Simon,

Painting the walls white can also make a huge difference to light levels. All the walls in my workshop are slightly off white and the floor is painted light green.

I heartily agree with the above advice.  My first workshop was a sectional concrete building that I lined, walls and roof, with 2" wood wool slabs.  Walking into there felt like entering a black hole!!!  I invested a few quid on a tub of cheap brilliant white emulsion paint and it absolutely transformed the place!!  It didn't take long to apply a couple of coats with a roller and the effect was dramatic, even though it only coloured the surface of the slabs and left the holes between the fibres their original grey.

I do realise, though, that it's much more difficult once the space involved has acquired contents!! 
Best regards,

Pete W.

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Offline John Rudd

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Re: Wiring advise for lighting.
« Reply #12 on: March 06, 2015, 12:29:08 PM »


Please do not put the lights on a RCD protected circuit machine trips it and you go dark
You can get at a price emergency tube fittings , but a small rechargeable torch that fits into a charging station will do the job

Stuart

Stuart

But if it goes dark , how you see the torch..... :lol: :lol: unless it's a-glow-in-the-dark torch..... Heheheheeeeee
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Offline S. Heslop

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Re: Wiring advise for lighting.
« Reply #13 on: March 06, 2015, 01:30:45 PM »
One thing maybe worth a moments thought.....add an emergency light in case of power cut/ blown fuse/ act of God etc.......just so you can see when the lights go out....??? :zap:

Fortunately the street lamps outside light the garage just barely enough to see in it.

As for painting the bricks... i've considered it but in all honesty I just like the look of the bare bricks. There's a few people on Youtube who've painted their workshops white for the sake of filming, and it always looks a bit depressing.

Anyways I got the lights hooked up. Lots of fiddling in awkward positions.



I've been measuring the light based on what my camera decides to use for its exposure, and previously I was getting about 1/8 of a second with the roof lights alone, but now it's getting 1/30th, so it's one hell of an improvement.

Thanks again for all the advise.

lordedmond

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Re: Wiring advise for lighting.
« Reply #14 on: March 06, 2015, 01:51:16 PM »
John
Point noted  :lol:

Most of the rechargeable torches that fit in a charging station will come on when the power goes off , they are sold for this very job you leave them turned on but when on charge they turn off until they lose power

 :D :D

Stuart

Offline petertheterrible

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Re: Wiring advise for lighting.
« Reply #15 on: March 06, 2015, 02:44:42 PM »
Try finding LED globes for those light bar sockets.  New fab, we installed them everywhere, especially in the 4 foot variety.  Most of the globes I buy are 18 Watt per bar and provide more light than the fluorescent versions do.  They cost just as much but are just so much better and you will save on electricity too.
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Offline awemawson

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Re: Wiring advise for lighting.
« Reply #16 on: March 06, 2015, 02:52:43 PM »
Peter, you don't say where on the planet you are, but here in the UK led replacements for fluorescent tubes are horrendously expensive.
Andrew Mawson
East Sussex

Offline petertheterrible

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Re: Wiring advise for lighting.
« Reply #17 on: March 06, 2015, 03:01:49 PM »
The thing about electricity is if it burns it burns,  :zap: so try to overrate by at least 15%.  It depends on the building codes where you live, but rather save than sorry.  I must add that the type of lights that you want to install wont draw their maximum amount when switched on, they tend to sputter on one after the other that will vastly reduce the load, the problem is that if the wire burns, it will usually happen when you left them on for a long wile, usually forgetting to switch them off.  Although these lights look big, they do not nearly use as much electricity as you would think.  Still need to put a couple of 16mm cables to run the 40 plus light we usually put in a smallish supermarket though.   :smart:

South-Africa. My electrician gets them for R85 (less than 5 pounds) a peace with a year guarantee, he rents one of my shops, and the agreement is that if one goes he should replace immediately.  Good advice, be the landlord of the guys that do your installs.
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Offline awemawson

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Re: Wiring advise for lighting.
« Reply #18 on: March 06, 2015, 03:51:53 PM »
They are a bit more here in the UK

http://www.lampshoponline.com/t8-6ft-28w-led-tubes-clear-high-output/?gclid=CIzs_YXMlMQCFQLMtAodP3UAFw

I'd love to change my workshop lights for these but as I have 67 tubes that's a capital outlay of over £3K  :bugeye:
Andrew Mawson
East Sussex

Offline dsquire

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Re: Wiring advise for lighting.
« Reply #19 on: March 06, 2015, 04:29:01 PM »
They are a bit more here in the UK

http://www.lampshoponline.com/t8-6ft-28w-led-tubes-clear-high-output/?gclid=CIzs_YXMlMQCFQLMtAodP3UAFw

I'd love to change my workshop lights for these but as I have 67 tubes that's a capital outlay of over £3K  :bugeye:

Andrew

You have to look at it the other way. Acording to the ad you would be saving £1,116.76.  :lol: :lol: :lol:

You have a nice bright day now  :D :D :D

Cheers  :beer:

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Offline picclock

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Re: Wiring advise for lighting.
« Reply #20 on: April 26, 2015, 04:05:38 AM »
 Hi S Heslop

I am in a very similar situation as I am moving to Dorset and will have to set up my workshop in a Double garage. However I have decided to have a go at lighting it with low cost LED strips. I am hoping to achieve lower running costs with better, more even, ambient illumination and a higher color rendering index. I am planning to put the strips between the rafters, recessed such that the 120 degree illumination angle is not affected.

These are 5 metres long, self adhesive backed, 300 led's per strip (600 option), allegedly rated at 20 lumen's per led with an angle of 120 degrees, at £3.80 per strip. Allegedly there are 1600 lumens in a std 100W incandesent bulb, 5800 in an 80W fluorescent tube (according to Philips). So in my £3.80 strip I should have 6000 lumens or about  a tube  :med:. The LED's use about 60W (12V at 5 Amp) but I am fairly sure that the light output figure for the tube from Philips is from all round the tube whereas the useable part is mainly the lower 180 degrees. Although the LED Strips are very low cost they will need a power supply, and I have purchased a 30 Amp supply for £17.50. I have also ordered a wireless controlled dimmer for £1.69 - which if it works will be amazing value.

When the parts arrive (mid May ??) I shall do a write up and comparison test with pictures in my thread under Electronics.

There are several issues I have encountered with tubes in the workshop. They take about 15 mins to warm up properly and give their best light. Electronic ballasts are amazing and flicker free. The tube outputs sneakily go down after time. I also had a nest of wasps inside one of the battens though you can hardly blame the technology for that  :drool:.

Best Regards

picclock


« Last Edit: April 26, 2015, 07:19:40 AM by picclock »
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Offline Arbalist

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Re: Wiring advise for lighting.
« Reply #21 on: April 26, 2015, 04:50:02 AM »
Welcome to Dorset. There's a good metal supplier in Ringwood if you need them, Ringwood engineering.

Offline picclock

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Re: Wiring advise for lighting.
« Reply #22 on: April 26, 2015, 07:13:13 AM »
Hi Arbalist

I'm moving to Ferndown, just a few miles from Ringwood. Looking forward to the good Ringwood Brewery Ales and the proximity of Ringwood Engineering. Have ordered stuff by post and visited them. Good people to do business with.

Best Regards

Picclock
Engaged in the art of turning large pieces of useful material into ever smaller pieces of (s)crap. (Ferndown, Dorset)

Offline awemawson

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Re: Wiring advise for lighting.
« Reply #23 on: April 26, 2015, 08:52:27 AM »
Ferndown is a nice part of the country. I used to be a regular visitor there as I had a client who offered computing facilities to solicitors and I had engineers based in their Ferndown office. Many an early morning start for breakfast meetings there :)
Andrew Mawson
East Sussex

Offline picclock

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Re: Wiring advise for lighting.
« Reply #24 on: April 29, 2015, 04:10:17 AM »
hi

The first and most frivolous part of the lighting parts has arrived - A wireless on/off remote dimmer - for the princely sum of £1.69 delivered. Its rated at 12A so I can control two strips together. Will likely buy more remotes and control them with just one controller. Operates at 433.92 MHz.

Best Regards

picclock
Engaged in the art of turning large pieces of useful material into ever smaller pieces of (s)crap. (Ferndown, Dorset)