Low voltage down-lights dimming.

[rustyj]

Hi All

I wonder if someone could help please.

I did my Part P about 2 years ago to rewire my house. All when well!!

I put low voltage down-lights in the hole house I got 7 in the lounge and 19 in the kitchen 12 on the mail side and 7 on the other side with two different switches and on it's own fuse.
I have noticed that my light in the lounge dim slightly when I switch the kitchen lights on and or my landing lights I have not noticed it any where else in thee house.

Does anyone have any ideas??

 

[KEVINDOE]

Are you saying that all these lights are on one circuit mate?

 

[DurhamSparky]

dimming Downlights, !

sudden pull of current due to the sheer amount of lights on circuit, similar when you see some powerfull showers kick in..some times lights dim a tad..

also correct sized lamps..??? not over sized the lamps?? 50w in a max 35w..

or you have exceeded the capacity on the transformer..!!

 

[rustyj]

Hi there DurhamSparky

The Lamps are 35w on a max 50w transformer I removed the 50w to solve the problem but has not completely stopped dimming.
Just to correct my first post I have 9 lights on the main side and 7 on the other side.

Is a bit of dimming normal??

 

[rustyj]

Yes they are all on one circuit.

 

[pushrod]

Hi there DurhamSparky

The Lamps are 35w on a max 50w transformer I removed the 50w to solve the problem but has not completely stopped dimming.
Just to correct my first post I have 9 lights on the main side and 7 on the other side.

Is a bit of dimming normal??

shouldn't get it but you are almost certainly getting too much voltage drop.

 

[GStueyXR]

obviouslt didnt teach voltage drop on your course mate....

Get some 2.5 cable in there, or split the circuit.

 

[ianbrookes]

if each downlight has it's own transformer then your have a voltage drop issue (as already mentioned) which means bigger cable - but this may not be the only issue. If you have this on one transformer then you should calculate whether it is sufficient to run the circuit(s), e.g. 9 times 35w would need a 315w+ transformer. If you have all these 42 lamps on one fuse then you could be overloading, i.e. 42 * 35w = 1470w / 230v = 6.4amps. Then again you have to calculate voltage drop by taking the length of the circuit, size of conductor, how the cable is installed (reference method) etc.. use the OSG to do this.

 

[rustyj]

Thanks for all your help!!!
I did not expect this kind of response Thanks

I think the easiest way to solve this from your response is to put a new fuse in the consumer unit and as I already have two 1.5 going back to the c-unit from my kitchen so I can split the curcit. ???

I am starting to building an extension in the new few months and will need to rip the floor up again, and I don't think the wife will be very happy if I have to do it again.

Thanks for all your help and will let you know how I get on.