UK Led downlighting goes off when job switched on ?

[Firetrekker]

Hi all, I’ve changed a board and then some time later went back to replace a dimmer that had failed. I’ve got 17 fixed led down lights on a switch which I swapped out feed from a 6a on a split rcd with the induction job on the same rcd on its own 32a.
With the down lights on, switching on the Hob turns them off. Any help would be appreciated!

 

[AJshep]

It could be a number of things, I'd be checking mis-termination/loose connections at the CU and accessories on all conductors.
When you turn the hob on do you lose the neutral or the line at the lights ?

 

[Firetrekker]

It could be a number of things, I'd be checking mis-termination/loose connections at the CU and accessories on all conductors.
When you turn the hob on do you lose the neutral or the line at the lights ?

I’ve not got back there yet, as I was told a few days later, but I’m happy with the board and the issue didn’t exist until I replaced the varilight dimmer .

 

[SparkyChick]

I have had one case of a Varilight dimmer module that would turn itself off when there was a smallish spike. It was in a dining room, controlling some Varilight transformers (1 transformer if I recall that powered 4 MR16s). The next light along the circuit was the bathroom, similar arrangement... 1 transformer, 4 MR16s.

When the bathroom light was turned on/off, the dining room light dimmer would crash and turn the lights off (they are microcontroller driven). I suspect if you change the dimmer module the problem might go away... I just picked up another module, replaced it and all was good.

I did have some contact with Varilight technical who tried to reproduce it but failed, so the advice to replace it was from them.

 

[AJshep]

I’ve not got back there yet, as I was told a few days later, but I’m happy with the board and the issue didn’t exist until I replaced the varilight dimmer .

Out of interest did you use a V-pro dimmer ? How close is the induction Hob to the dimmer ? It could be the once the Hob is turned on it the noise/ frequency is getting picked up by the dimmer and amplified. I know V-pro dimmers are notorious for going into setup mode which will turn the lights off and on again.

 

[SparkyChick]

The interesting thing is, I've installed a whole bunch of these, and that job had a dimmer in nearly every room. It was only the dining room one that had the problem.
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For reference, in my case, it was a vPro.

 

[Firetrekker]

Hi, no wasn’t a Vpro but was an LED specific one. I will go with the obvious and change the dimmer, will let you know how I get on. Thanks for your advice ?

 

[Lucien Nunes]

As a first step I would double check whether the lighting circuit is still getting 230V within tolerance when the hob is turned on. This would eliminate any wiring issues and point towards radio / cable-borne interference with some certainty.

In that case it takes two to tango - the dimmer is probably unduly sensitive to the interference but the hob could be radiating more interference than it should.