Replacement dimmer switch not working (at all)

[7pillars]

Hi, an old dimmer switch stopped working (it actually 'popped' and a blue light flashed inside the mounting box). Figuring it was the dimmer itself I tried replacing it with a new one.

The old one was plastic 240W with the earth cable fixed in the mounting box, and the new one is brass 400W where it seems the earth cable needs to be attached to the cover.

2 questions: does it matter that I am replacing a 240W dimmer with a 400W dimmer (controlling a single 'standard' light) and is it imperative that the earth cable is attached to the brass cover and not the mounting box?

 

[EFLImpudence]

does it matter that I am replacing a 240W dimmer with a 400W dimmer (controlling a single 'standard' light)

No - unless there is a minimum which is higher than the lamp.

and is it imperative that the earth cable is attached to the brass cover and not the mounting box?

Yes - to both would be good.

 

[7pillars]

Thanks for the reply.... based on the way the old dimmer 'failed', does it sound as though the problem could be more serious than just a broken dimmer switch?

 

[Taylortwocities]

Sometimes the bulb going will take out teh dimmer too, so check teh lamp hasnt gone pop too.

An easy way to check is to koi the two wires together in the switch box. That will confirm all the wiring and the lamp itself.

Turn the power off at the fuseboard first!

 

[PrenticeBoyofDerry]

is it imperative that the earth cable is attached to the brass cover and not the mounting box?

The earth/CPC must be attached to the switch plate and depending whether the backbox is metallic and if it was rigid screw lugs or moveable ones, would determine if a the earth/CPC should also be bridged across plate and backbox, but belt/brace, safe/sorry would recommend doing it anyway!
I would also suggest for safety reasons that you actually had it proved via test, that a path back to earth at the supply was present.