Minor electric shock with the power off... faulty circuit breaker?

[MagMrMax]

Did you use tester on live and neutral, got a shock once with power off , live and neutral had been reversed.

I didn't have a tester with me when I was replacing the switch. I don't have one at present, but I can borrow one.

 

[SUNRAY]

Did you use tester on live and neutral, got a shock once with power off , live and neutral had been reversed.

It's not that uncommon.
First time I found it I'd pulled the lighting fuse to work on a fitting then managed to short N together.

 

[SUNRAY]

Did you use tester on live and neutral, got a shock once with power off , live and neutral had been reversed.

It's not that uncommon.
First time I found it I'd pulled the lighting fuse to work on a fitting then managed to short N & E together.

 

[crystal ball]

Lots of people poo poo voltsticks but they come into their own at times

 

[MagMrMax]

Can anyone indicate what it is I should be testing when I do get the multimeter, please?

Or is it more a case of turning off every switch on the main CU and then going upstairs to see if the bedroom lights are still on?

Thanks

 

[securespark]

If you check voltage at that switch position with a multimeter between live and earth, with the main CU switched off and get a reading, then that light must be fed from elsewhere.

 

[JohnW2]

To put an end (one way or the other) to all the speculation going on here, could you switch off everything (just) in the secondary ('shower') CU and then tell us whether the bedrooms lights still work?

Kind Regards, John

 

[endecotp]

To my knowledge, this was fitted to supply the shower only.

Lazy ****ers couldn’t be bothered to write in what the two switches do.

You should now fill them in. The right-hand 40A one is the shower and the left-hand 6A one is (some of) the lights.

Can someone comment on the acceptability of having no “main switch”, but only an RCD and MCBs, in that second CU?

 

[MagMrMax]

To put an end (one way or the other) to all the speculation going on here, could you switch off everything (just) in the secondary ('shower') CU and then tell us whether the bedrooms lights still work?

Kind Regards, John

Lazy ****ers couldn’t be bothered to write in what the two switches do.

You should now fill them in. The right-hand 40A one is the shower and the left-hand 6A one is (some of) the lights.

Can someone comment on the acceptability of having no “main switch”, but only an RCD and MCBs, in that second CU?

I switched off just the smaller "secondary" CU. Lo and behold, the shower went off (as expected), but so did 5 of the 8 upstairs lights, including the one I had been working on.

So it had been live whilst I was working on it.

I have written a large warning on both CUs now and labelled the 40A and 6A fuses in the "secondary" as advised.

Thank you one and all for your help!

 

[sparxxxx]

None of this would have arisen if your shower installer had issued full certification.

 

[MagMrMax]

In my defence, I'm just a layman.

I hired him to install the shower wiring, and that's all I thought he did.

I honestly didn't know he'd done anything else, he definitely never said he'd re-routed some of the lights, and no paperwork/certification ever changed hands (again, I wasn't aware that I should have received some).

Needless to say, I won't be using him again.

 

[sparxxxx]

I switched off just the smaller "secondary" CU. Lo and behold, the shower went off (as expected), but so did 5 of the 8 upstairs lights, including the one I had been working on.

I would get an electrician to investigate exactly what he has done to your lighting circuit. I would have expected one light to ge OFF, and five out of eight seems odd to me

 

[EFLImpudence]

Can someone comment on the acceptability of having no “main switch”, but only an RCD and MCBs, in that second CU?

The RCCB is the main switch (for that CU). There would be little point in having a second next to it.

 

[crystal ball]

None of this would have arisen if your shower installer had issued full certification.

I doubt a DIYer would pull out the certs and read them before swapping switch, even if he could find them

 

[crystal ball]

I would get an electrician to investigate exactly what he has done to your lighting circuit. I would have expected one light to ge OFF, and five out of eight seems odd to me

Depends on the layout of the house surely