LED lights blowing - is it the (old) consumer unit?

[ReactLED]

I have a very odd problem to do with LED lighting.

The customer had a string of 10 x 40 Watt incandescent lamps, connected to a dimmer switch. We replaced the dimmer switch with a Varilight V-Pro trailing-edge dimmer so that he could use 10 x 3 Watt LED candle lamps instead.

Whenever I switched the circuit on, one of the LED lamps blew, taking the cartridge fuse in the Hagar fuseboard with it. The only way to prevent this happening was to leave 4 incandescent lamps in the string (so he had 6 x LED and 4 x incandescent lamps in the same circuit). An hour after doing this, the fuse blew again, taking out another LED lamp and the trailing-edge dimmer switch.

To eliminate some possibilities up front:

• The fittings appear to be correctly connected and in good order
• The LED lamps are good - they are dimmable, and we have installed over a hundred (with and without dimmers) from the same batch for several other customers who have been using them for months without losing a single lamp.
• The fittings are open, and the lamps are not overheating.

The only differences between this job and our others (which are perfectly reliable) are:

• The building is in a relatively relatively isolated position in rural Devon
• The electrical installation is quite old (as indicated by the Hagar fuse board with no RCD protection). All of our previous installations have made use of more up-to-date consumer units

Any suggestions are most welcome. Thanks in advance.

John

 

[Octopus]

Think start up currents!

 

[FAA Greenie]

Think start up currents!

Can you expand on that for us?

I'm fairly sure that the dimmer mentioned in the OP is current controlled/soft start/over volt protected etc.....

The only reason i ask is i have had a similar problem not so long back, it turned out that when the kitchen light was turned on (twin 4' tubes), the LED's dimmed, and then readjusted to normal. This went on for a few weeks, then the dimmer blew. I assumed at the time that it was just being over whelmed by voltage spikes during the kitchen light start up and eventually gave up the fight.

I'm going back next week to replace the kitchen lighting so I'm hoping that this will solve the problem.

 

[GLENNSPARK]

split the load...

 

[FAA Greenie]

There were only 6 LED's in my set up

 

[specs]

I had same problem a while back, i removed dimmer and replaced it with standard switch and all was well. took dimmer back to supplier, turns out they had a faulty batch. I don't think they have quite mastered this technology yet, it is constantly being updated. It seems everytime i visit my supplier they have a new dimmer or lamp that overcomes the problem of flicker/dimming range and blowing lamps. These items are not cheap to replace . I have never had a problem when i use straight forward switching, so now i tend to split the lighting into groups of two,three or even four gangs on the switch ,depending upon how many lights required in a room. Not the same i know, but until i can find a reliable dimmer that is not vunerable to slight variations i will stick to this. If anyone knows of an LED dimmer and lamp supplier/manufacturer that has any sort of proven track record i would be glad to hear from you. LED is definatly the way forward.Thanks