Ask an Electrician anything...

[Tailender Investor]

Prisoner 24601 said:

I have a question for an electrician, or whomever else may know the answer.

As part of a wider package of jobs, we had a local domestic electrician and his colleague round a few weeks ago. One of the (easier) jobs was to install a new light fitting in the hallway, however, the instructions were fairly adamant that it should be fixed to a joist, and i couldn't locate a joist anywhere near where the cable was popping out the ceiling. So I thought i'd leave it and bundle it together with the other jobs for the expert.

When they came to do it, they spoke amongst themselves, got it all prepped and ready to go - then they said to each other, as they felt the weight of the fitting wasn't that great, they would ignore the need for a joist and...here goes...."just fix it straight into the box". I didn't stand there staring at them, i was in the dining room 'working'. I noticed they drilled a new circular hole, but i didn't see what 'box' they put up there, how they put it up there, how the box is fixed in an empty ceiling void and what this so called box is.

Any ideas guys? I might need to repeat this for the upstairs hallway fitting.

I would guess a circular drylining back box.

[ruggedscotty]

KnackeredOldBanger said:

Very simple one but are you aware of any single module doorbell transformers that will suit a Wylex consumer unit? My board has one spare din rail space for it to sit in but the only Wylex transformer I can find has been discontinued so not sure it's a good idea to fit? Might not meet regs etc.

https://www.ebay.co.uk/itm/265012841014?mkevt=1&am...

Or is it ok to mix manufacturers within the CU? Some seem to say yes, others no. Not sure whether that's just electricians being pedantic though?

I know it's an expensive way of doing it and I could just put a separate transformer outside the unit, but I'd like to have it all in one place if possible.

Edited by KnackeredOldBanger on Sunday 18th June 10:47

dont mix and match - its a nightmare doing that - fit an external transformer. unlrss you can get the proper one. Its always the connection to the busbar that gives the most trouble.

[ruggedscotty]

Tailender Investor said:

Prisoner 24601 said:

I have a question for an electrician, or whomever else may know the answer.

As part of a wider package of jobs, we had a local domestic electrician and his colleague round a few weeks ago. One of the (easier) jobs was to install a new light fitting in the hallway, however, the instructions were fairly adamant that it should be fixed to a joist, and i couldn't locate a joist anywhere near where the cable was popping out the ceiling. So I thought i'd leave it and bundle it together with the other jobs for the expert.

When they came to do it, they spoke amongst themselves, got it all prepped and ready to go - then they said to each other, as they felt the weight of the fitting wasn't that great, they would ignore the need for a joist and...here goes...."just fix it straight into the box". I didn't stand there staring at them, i was in the dining room 'working'. I noticed they drilled a new circular hole, but i didn't see what 'box' they put up there, how they put it up there, how the box is fixed in an empty ceiling void and what this so called box is.

Any ideas guys? I might need to repeat this for the upstairs hallway fitting.

with light fittings your always wary of what shade they will fit, so tend to want to err on the side of caution.

Always like to have it affixed and not reliant on the plaster board

I would guess a circular drylining back box.

[Prisoner 24601]

Tailender Investor said:

Prisoner 24601 said:

I have a question for an electrician, or whomever else may know the answer.

As part of a wider package of jobs, we had a local domestic electrician and his colleague round a few weeks ago. One of the (easier) jobs was to install a new light fitting in the hallway, however, the instructions were fairly adamant that it should be fixed to a joist, and i couldn't locate a joist anywhere near where the cable was popping out the ceiling. So I thought i'd leave it and bundle it together with the other jobs for the expert.

When they came to do it, they spoke amongst themselves, got it all prepped and ready to go - then they said to each other, as they felt the weight of the fitting wasn't that great, they would ignore the need for a joist and...here goes...."just fix it straight into the box". I didn't stand there staring at them, i was in the dining room 'working'. I noticed they drilled a new circular hole, but i didn't see what 'box' they put up there, how they put it up there, how the box is fixed in an empty ceiling void and what this so called box is.

Any ideas guys? I might need to repeat this for the upstairs hallway fitting.

I would guess a circular drylining back box.

Thank you very much. That looks good. So, as you screw something into the screws, it pinches the blue plastic bit down against the plasterboard creating a moderately strong fixing.

[KnackeredOldBanger]

ruggedscotty said:

dont mix and match - its a nightmare doing that - fit an external transformer. unlrss you can get the proper one. Its always the connection to the busbar that gives the most trouble.

Would you see any issue with the one linked to on eBay?

[ruggedscotty]

KnackeredOldBanger said:

ruggedscotty said:

dont mix and match - its a nightmare doing that - fit an external transformer. unlrss you can get the proper one. Its always the connection to the busbar that gives the most trouble.

Would you see any issue with the one linked to on eBay?

If its different to the DB make yup. Try and match and even if your matching make sure its the type for the board you have.

You could also get a seperate box with din rail to suit ?

That way its sorted and you dont need to worry about mix and match to the board itself

[Gareth1974]

I sometimes get an electric shock, usually mild, from the dishwasher and toaster.

I’m not 100% sure the earth on my house is correct. It’s a rod stuck into the ground, an arrangement I’ve not seen at other houses.

[Yabu]

Gareth1974 said:

I sometimes get an electric shock, usually mild, from the dishwasher and toaster.

I’m not 100% sure the earth on my house is correct. It’s a rod stuck into the ground, an arrangement I’ve not seen at other houses.

Looks like it is a TT earthing system, plenty of properties have this type of earthing, but nowhere near as common as the other types of earthing,if your getting shocks the. Further investigation by an electrician is needed;

[Kurtville]

We have an electric shower with an extractor fan which comes on when the light switch is turned on. This is right next to our bedroom and the noise from the fan is really annoying in the night when someone uses the bathroom. The extractor is only needed when the shower is being used. Is it possible to connect the extractor to the double pole switch for the electric shower so that it only comes on when the power for the shower is turned on?

[Trustmeimadoctor]

Could just use a humidistat

Or if possible replace a cheap ceiling fan with a bigger inline unit

Then it will still come on but it will be much quieter

[RichB]

The extractor above our shower simply has a switch in the same bank as the bathroom light switches. We only turn it on when we use the shower.

[dlks151]

Gareth1974 said:

I sometimes get an electric shock, usually mild, from the dishwasher and toaster.

I’m not 100% sure the earth on my house is correct. It’s a rod stuck into the ground, an arrangement I’ve not seen at other houses.

Could you provide a picture of the supply authority cable head, this would give us an indication on what type of incoming supply type you have.

Notwithstanding the above, I'd suggest you have an electrician attend and carry out a fall of potential test on that earth rod. Earth rods are generally 1200mm in length and yours has been cut down, it could be that it is coupled to another rod and has been driven to a set but that's very unlikely.

[Kurtville]

RichB said:

The extractor above our shower simply has a switch in the same bank as the bathroom light switches. We only turn it on when we use the shower.

Thought about that but don't really want to have a bank of three pull switches!

[dhutch]

Kurtville said:

RichB said:

The extractor above our shower simply has a switch in the same bank as the bathroom light switches. We only turn it on when we use the shower.

Thought about that but don't really want to have a bank of three pull switches!

These days there should be a 3-pole fan isolator which will turn the lot off, but as you say that's not really what you want.
You can also likely adjust the fan over-run timer to zero so it goes off straight away when the light goes off, which might help.

In my last house I installed an extra pull cord next to the light pull cord.
- Pull the light one, which was nearer the door and had a nice pull end, and you just got the light for nipping to the loo.
- Pull the other one, which was a plain pull, you got the light and the fan for when you wanted to have a shower etc.

This saved having to pull two cords when you where having a shower, but if you used one to turn the light on and the other to turn the light off, it would blink and come back on again! but if you pulled the other one, it would then go of, and if it was off it was obviously off. The isolator for the power shower was the other side of the room and never switched off.

[mickk]

Have a pir installed near the shower controlling the fan.

[dhutch]

mickk said:

Have a pir installed near the shower controlling the fan.

With enough digression not to trip off when you go to the loo? That s a nice solution. Presumably far enough away to be outside of any zoning too?

[dhutch]

dlks151 said:

Notwithstanding the above, I'd suggest you have an electrician attend....

Yeah, very hard to fault find that sort of thing remotely. Obviously hasn't killed you yet, but there shouldn't be voltage on the casing of those items!

[Regbuser]

Kurtville said:

We have an electric shower with an extractor fan which comes on when the light switch is turned on. This is right next to our bedroom and the noise from the fan is really annoying in the night when someone uses the bathroom. The extractor is only needed when the shower is being used. Is it possible to connect the extractor to the double pole switch for the electric shower so that it only comes on when the power for the shower is turned on?

Install battery powered PIR activated under counter lights, like these > https://www.amazon.co.uk/Cabinet-Wireless-Adjustab...

[Trustmeimadoctor]

The other alternative is a pir lamp we have one in the bottom of the vanity unit that provides light as it's wired in as permanent live

It's a nice soft light that doesn't shock you awake as an additional benefit

[RichB]

Kurtville said:

RichB said:

The extractor above our shower simply has a switch in the same bank as the bathroom light switches. We only turn it on when we use the shower.

Thought about that but don't really want to have a bank of three pull switches!

Ah... our switches are normal ones on the outside of the room by the door.