LED GU10 lighting max number per circuit , circuit design, dimmers

[lazy username]

Hello everyone,
lately alot of customers have been asking to change there standard 50watt lv halogen spotlights for the more energy efficient LED gu10's.
My question is... is there a max number of these that can be on a circuit?

Previously the rule of thumb was 10 but with the loads considerably lower has this changed??

Obviously mcbs will have to be changed to suit the load and dimmers will have to be changed to the TRIAC or SCR type.

Also when first fixing should I design my circuits (except protective devices at DB)for 50w gu10 halogens incase the customer decides when Ive left that he is not happy with the light he is getting from his leds and decides to change them back or gets the wrong replacement when one blows ??

Apologies for my ignorance but Ive been out of work and back in college for awhile, Im still catching up with changes to the regs

 

[D80]

Best to check manufacturers instructions. As far as I know the likes of the Halers have a limit of around 14 fittings per circuit.

 

[Strima]

I would design the circuit to take halogen GU10's, you never know what will be put in at a later date. That includes protective devices.

 

[Barry Rathbone]

3w GU10 as a guide 16 to 1 ration ish, Would you not go for as many as required to light the room to a satisfactory lumens value?
I have 10 in a 4x5m room which have daylight 3w leds in.
Loading isn't an issue as you are going to put in a 6/10A Mcb to suit cables installed. 200 GU10 50w @43AMPS..........200 Downlights of 3W @ 2.6 A approx...Your not going to fit THAT many surley in a house...
I recently had 46 50w gu10 to change in a houseOn 3 Circuits btw..., and because they got so hot as someone had placed boarding over the top the cable almost set on fire.(2300w 8-9 hrs a day) to (138W 46 x 3 8-9hrs a day) And a happy customer,VERY HAPPY..

So no I would most certainly tell anyone NOT to refit halogens.Apart from the overall electric cost led's last longer and are a better light output.IMO...
GU10 50/32/20 w halogens will be phased out HOPEFULLY!! so to retrofit isnt an option.....Nudges Goverment Body....

 

[Darkwood]

Yes strima nailed this one, you have to assume that 50Hal are fitted even if you have 3w LED's gu10 in etc as there is nothing stopping an unsatified customer changing them, also as no-one has mentioned is the limiting factor of the led drivers with inrush, either manufacturers guidelines or mcb guideline should be sort if you want to have a large no' per circuit like Halers which cant be up-rated to 50w hals.

 

[Barry Rathbone]

Are all customers going to be happy paying £30-40 a fitting.. loses job to GU10 LED lads? Agree with what you say though.
If designed right the customer won't have to change to Halogen surely?

http://www.howmanylights.co.uk/FlashTools/FlashIndoor.aspx?InstanceKey=194|DL-XX-F-NW.ies

 

[Strima]

It's not a case of having to change to halogen. If the fittings are capable of taking them there is the possibility of them being fitted in the future either through choice or accident, that's why I always design and install to the worst case scenario within reason. As for price, whatever the customer wants to pay, but some people can't see the long term benefits over the short term cost.

 

[Octopus]

Shouldn't your design calcs "assume" 100w per point irrespective of what is actually being fitted??

 

[Strima]

This is where it gets a little grey. You could feasibly replace all the GU10s for BC fittings but this would be down to the person installing the new fittings to decide of the circuit and OCPD are capable of taking the new load.

No problems when it 1/2 a dozen fittings in a kitchen but when there's numerous amounts all over the house things start getting silly. That's why I like to split circuits down and say provide three instead of one. All boils down to cost, usage, type of property etc.

You can't design for stupidity and there are so many variables I do it on a case by case basis.

 

[Current Affairs]

If you are just changing from 50w standard GU10's to lower voltage GU10 LED bulbs, cannot understand why you are rewiring. Just change the bulbs, I buy mine direct from ever ready off the net, in boxes of 100, keeps the cost of them down

 

[Barry Rathbone]

If you are just changing from 50w standard GU10's to lower voltage GU10 LED bulbs, cannot understand why you are rewiring. Just change the bulbs, I buy mine direct from ever ready off the net, in boxes of 100, keeps the cost of them down

Yup, of course... retrofit is the word...He's replacing so THE installations already suit 50W halogens..
I showed the savings of course! :wink5:

 

[Darkwood]

Shouldn't your design calcs "assume" 100w per point irrespective of what is actually being fitted??

This is i was also taught but this was long before gu10 etc that cant exceed 50watts and the old recess spots used to be PAR lamps 60/80/100watts so it covered all lighting to stamp it with 100watt per point, times have changed so do the guidelines.

 

[Farmelectrics]

So I have 21 led gu10 4w on my upstairs lighting circuit been like that for over 12 months are you saying there should be only 14 and I should pull another lighting circuit in can't see the problem my self there on a 6 a mcb and only pulling 84a your thoughts chaps

 

[Darkwood]

So I have 21 led gu10 4w on my upstairs lighting circuit been like that for over 12 months are you saying there should be only 14 and I should pull another lighting circuit in can't see the problem my self there on a 6 a mcb and only pulling 84a your thoughts chaps

In a nutshell Yes.... if its possible to uprate the lamp then you have to design for the max possible load, just a senerio for you but to highlight the issue, say you won the lotto then bought big house moved out and got on with your carefree lifestyle, dear old lady buys your house but thinks that the 4w (35w equiv in lux roughly) is too dim so she gets her dear son to fit 50w hals instead, then on a minimum you have nuisance tripping and depending exactly on circuit design possible fire hazard.... either way as this of a thousand senerios can happen then its to be taken into the design.

 

[Barry Rathbone]

Its ludicrous but alas until Halogen lamps are banned(building regs energy effeciencies blah blah blah!) then cough! My house is fine I'm not stupid..Quiet at the back!! until I sell then... where was that can of worms...

 

[Darkwood]

Dont get me wrong, i see and can agree in part with both sides of the argument but yes until 50w hals are discontinued and prob 5yrs have passed for old stock sales then its to be done this way, so looking at possibly 2020 before we can relax this one, only a new lamp holder designed specifically to accept a new LED lamp range will get round this quicker

 

[Farmelectrics]

Well even if they changed LEDs back to 50w halogens the circuit would only be pulling 2kw it's wired in 1.5mm so you could up the breaker to 10amp what's the problem with that

 

[Farmelectrics]

Are we saying the most gu10 we have on 6 amp circuit is 14

 

[keniff]

I'd have to say 50w per fitting and taking into account the 6 amp mcb will protect the cable, I would be more than comfortable fitting more than 14?

 

[Strima]

Without taking into account any inrush current you could in theory get away with 27 50W GU10 on a 6A MCB.

Using a 10A MCB you could get up to 46 lamps on a circuit. Both these calculations are right on the operating current of the OCPD.

Or my maths could be way out... :lol: