Lighting....6 pendants wired individually from one junction box

[walberto]

Hi

My friends electrician father wired in some lights for him, originally taking a feed from switched live in junction box to 3 separate pendant lamps, so that's 3 separate cables running from the junction box to the lamps. This set up worked, the father then added 3 more lights in the same way, so now there are 6 cables running from the junction box. This also worked until my friend wanted a dimmer added. There are 6 x 70W lamps, and the dimmer was 500W. It worked for about an hour but then it popped and the dimmer function does not work. The lights can only be turned on and off. My friend has asked me why but I couldn't find a suitable explanation. I would have thought putting a higher wattage dimmer may resolve the issue, but thought I'd check with some qualified chaps before making any suggestions.
Thanks.

 

[Paul.M]

420W on a 500W dimmer is fine but after an hour? Take it back to B&Q and replace it.

 

[telectrix]

2 more pendants and you've got a proper spider. hate to think how the screws in that JB are getting a purchase with all those cables.

 

[Guest55]

Agreed ^^^
God only knows why the wiring hasnt been looped in / out from the pendants lol , at least reduce the no. of feeds from 6 to 2.
As for dimmer , should work with the load mentioned so take it back

 

[Guitarist]

What type of lamp are they?

 

[AndyL]

Are there any transformers feeding the 6 dimmer controlled lamps. If so may need to down rate the dimmer, usually about 80% so 500w dimmer can control 400w of inductive loads, but need to check manufacturers instructions 1st

 

[trev]

So what does your "friend's electrician father" say about it?

 

[DurhamSparky]

silence..............

 

[Moses]

Are there any transformers feeding the 6 dimmer controlled lamps. If so may need to down rate the dimmer, usually about 80% so 500w dimmer can control 400w of inductive loads, but need to check manufacturers instructions 1st

If dimmers are from a reputable manufacturer,
then if the dimmer is designed for your type of load, you would normally not need to derate the dimmer.

If however, you buy cheap, with no pedigree, then

For inductive loads derate the dimmer by as much as 50%

For Halogen and incandescent lamps ( where the inrush current is 10x steady state ),
dimmers should also be derated by 50-80%(i.e. 0.5 x and 0.2 x the stated dimmer rating)

 

[Guitarist]

I love how these threads always end up as a "chat" between the regular members

 

[jimmymac]

2 more pendants and you've got a proper spider. hate to think how the screws in that JB are getting a purchase with all those cables.

THREAD LOCK!! :cheesy:

 

[DurhamSparky]

then we get told off for going of subject....