Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[MichaelG]

I have LD11 dimmers fitted to control all my lights. Some of my light fittings take 240V (I live in the UK) GU10 bulbs which can be dimmed. However when the bulbs blow they cause the circuit breaker to be activated and normally the fuse in the LD11 blows as well. Occasionally the LD11 itself dies and I have to buy a replacement. Are there any ways to avoid the LD11 breaking? Is there a different fuse I should use?

I assume that the LD11 fuse will always blow when the bulbs go and there's nothing I can do about it. Is my assumption correct or are there other steps I can take.

[dave w]

There is little you can do.
The failure is caused by a current surge created as the filament separates (that nice blue flash you see in the bulb as it blows).

In the US the usual failure mode is the triac shorts.  In the North American X10 design, the fuse does not protect the triac. The failure is the module can never turn OFF.

A decade ago there was a study that identified Phillips brand, standard incandescent bulbs less likely to cause the failure because they have more robust supports on the filament coil. Halogens (GU10s) have a very stubby and well supported filament so better filament support really isn't a consideration.

If your modules have the soft start feature it will reduce the chances of module failure, but not eliminate.

[Brian H]

The LD11 Manual says it has soft start.
Do your lights take about 2.5 seconds to dim and brighten?

Are you using the T2.5 amp fuses as replacements?

I agree with dave w. Sounds like one heck of a surge when they blow.