Discuss After some advice (dimmer switch) in the UK Electrical Forum area at ElectriciansForums.net

Ccx295

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hi all,

Recently I have moved into a house which has a fairly old fuse box (no RCD) which I have planned on upgrading sometime next year.

The other night in our living room when turning on the main light (dimmer switch) there was a noticeable bang (crack) and maybe a small flash of light from the switch itself which caused a bulb to blow. This also caused the rest of the lights connected to the same switch to stop working until I removed the faulty bulb...

Now I didn't think too much of this at the time until the next day when I went to turn off the same lights and couldn't. The switch was also warm to touch and it was making sizzling noises.
So I switched off the power to the house and removed the switch.
The backing of the switch had partially melted which had left plastic residue covering parts of wiring covers.

Since this I have bought a new standard switch (not a dimmer switch), cleaned up the wire covers the best I could to remove the melted plastic and fitted the new switch and now everything seems to be working as it should apart from I can still smell the "burning" smell from new switch if I sniff it closely.
My other half just thinks it is the smell from before when the old switch was burning and it is just lingering and so do I, but i just want to make sure this is normal?

It is also not hot to touch.

Should I fast track a RCD upgrade after this? Would it have tripped when facing these issues?

Thanks for any advice in advance

Mac
 
I suspect the lamp failed and killed the dimmer rather than vice versa, as this is quite common. I expect you are right about the smell just lingering. An RCD would not usually trip on this sort of fault. (Not unless the resulting soot was bad enough to conduct sufficient current to the backbox, assuming it is metal and earthed, or through the exposed screws and someone touching them if the backbox is metal but not earthed.)
 
hi all,

Recently I have moved into a house which has a fairly old fuse box (no RCD) which I have planned on upgrading sometime next year.

The other night in our living room when turning on the main light (dimmer switch) there was a noticeable bang (crack) and maybe a small flash of light from the switch itself which caused a bulb to blow. This also caused the rest of the lights connected to the same switch to stop working until I removed the faulty bulb...

Now I didn't think too much of this at the time until the next day when I went to turn off the same lights and couldn't. The switch was also warm to touch and it was making sizzling noises.
So I switched off the power to the house and removed the switch.
The backing of the switch had partially melted which had left plastic residue covering parts of wiring covers.

Since this I have bought a new standard switch (not a dimmer switch), cleaned up the wire covers the best I could to remove the melted plastic and fitted the new switch and now everything seems to be working as it should apart from I can still smell the "burning" smell from new switch if I sniff it closely.
My other half just thinks it is the smell from before when the old switch was burning and it is just lingering and so do I, but i just want to make sure this is normal?

It is also not hot to touch.

Should I fast track a RCD upgrade after this? Would it have tripped when facing these issues?

Thanks for any advice in advance

Mac
You would do better to get the wiring checked out by an Electrician, after all fast tracking the RCD update would make the house safer but it would be a waste of time and money if the wiring was suspect, see what an electrician has to say
 
MK dimmers used to be fused so when the lamp blew it took the fuse out and not the dimmer.

Personally I think the smell is just lingering, its like when you microwave bread the small hangs around for ages.........
 
when you changed the switch ,are the conductors for the switch in the
terminals !

Everything was tightly connected.

So after about 4 days of use I have removed the switch to check to see if everything still looks OK, which it is and there is no sign of this switch burning up.

My only concern is the state of the insulation covering the wires, especially the black wire - It still has a fair amount of the melted plastic covering the end near the connection.
I don't want to try to scrape the plastic off too hard and it ends up pulling away the rubber and exposing the wire.
Normally I would just cut the wire back but there isn't any spare length to play with.

I have attached some pictures of the wires so you can see. The black marks on the red insulation is the residue from the melted plastic.

Will they be OK like this? From what I can tell there is no exposed wire.

Thanks again

image5.JPG

image4.JPG

image1 (2).JPG

image2.JPG
 
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I'd get that looked at, said the actress to the bishop. Might be cosmetic, but best get someone to check it out, preferably a competent electrician.
 
looks to me like the backbox is barely deep enough for the switch without cables , those cables look like they have been squashed between the switch mechanism and the backbox
 
Yes it does look quite shallow.

I think I'll get someone round to quote us for a new RCD box and and maybe they will have a look at this whilst they are here
 
Yes it does look quite shallow.

I think I'll get someone round to quote us for a new RCD box and and maybe they will have a look at this whilst they are here
is it concrete walls that have been raggled? cant tell whats behind the box from picture, if so making the box deeper is not much of an issue, if it was my house id have those damaged cables stripped back to healthy copper and re-connect
 
And the best way to do that would be to refit 4" higher up the wall with a deeper box. then the cables would be long enough to strip back.
 

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