Solve an argument: Should you turn ALL of the main switches off when working on electrics.

[reoreborn]

Sorry. A bit of an odd one.

Last night I was replacing plug sockets upstairs of a relatives house. On the main board I switched off the upstairs sockets (as labeled on the board), went upstairs and checked to make sure there was no electric to the plugs. I didn't lock off the board as it was only me and a relative in the house.

During this a neighbour came around for a cup of tea with my relative. When he found that I'd only turned off one switch he came bounding up the stairs moaning that what I was doing was dangerous. I asked why and he said "When working on electrics you turn ALL the switches off AND the main switch". He's a rather odd bloke and was going a bit off the rail. so I went along with his request and turned them all off to calm him down.
I am an amateur but I am able to replace plug sockets and have done it for over 25 years. This morning he sent me a screenshot of a website (a dodgy forum) that confirmed what he'd said.

Who is in the right/wrong on this one? I am 99% sure my way is the correct way but as I say I'm an amateur..

 

[Wayners]

I throw the main switch and that's it.
If you short the earth out while working on electrics it trips the main switch anyway but best to turn the lot off.
Also test power is off.
As for stitches on plugs I've never seen that done.

 

[EFLImpudence]

If you short the earth out while working on electrics it trips the main switch anyway but best to turn the lot off.

Main switches do not trip.

If you only turn off an MCB, then touching Earth and Neutral will probably trip an RCCB (Residual Current Circuit Breaker) which usually covers several circuits.

 

[opps]

If you are turning off the main switch, I cannot see what would be gained by turning off each individual MCB. And if it is getting dark, by flicking the main switch, you will need to use supplementary lighting. Like you, I just flick off the MCB in question.

 

[DetlefSchmitz]

As a non-professional, it's whatever you feel safe with, provided you have a full understanding of the risks involved, and act appropriately. Having said that, anyone giving advice to someone else, is more or less obliged to say 'turn of the main switch' as otherwise you could be considered liable for any bad consequences.

 

[Tigercubrider]

I always turn both off, just belt and braces.
I don’t think it is necessary, but the switches are next to each other.
Also, I have a Rechargable self contained LED flood worklight, should I need to work after dusk.

The neighbour’s wrong and the above is just me

 

[opps]

I always turn both off, just belt and braces.
I don’t think it is necessary, but the switches are next to each other.
Also, I have a Rechargable self contained LED flood worklight, should I need to work after dusk.

The neighbour’s wrong and the above is just me

Sorry, in no way am I being critical, but if you turn off the main switch, why turn off the MCB as well?

 

[opps]

Sorry. A bit of an odd one.

Last night I was replacing plug sockets upstairs of a relatives house. On the main board I switched off the upstairs sockets (as labeled on the board), went upstairs and checked to make sure there was no electric to the plugs. I didn't lock off the board as it was only me and a relative in the house.

During this a neighbour came around for a cup of tea with my relative. When he found that I'd only turned off one switch he came bounding up the stairs moaning that what I was doing was dangerous. I asked why and he said "When working on electrics you turn ALL the switches off AND the main switch". He's a rather odd bloke and was going a bit off the rail. so I went along with his request and turned them all off to calm him down.
I am an amateur but I am able to replace plug sockets and have done it for over 25 years. This morning he sent me a screenshot of a website (a dodgy forum) that confirmed what he'd said.

Who is in the right/wrong on this one? I am 99% sure my way is the correct way but as I say I'm an amateur..

Something tells me that if you had turned off the main switch initially, he might have complained about the kettle not working...

 

[ETAF]

i just turn of MCB - BUT not a professional registered electrician & for DIY , self or family ONLY
been doing that for years
sometimes i have tripped the BOX , but rarely

with lighting , depending on how its wired , i have just switched off the light switch - BUT then i know what i'm looking for, wiring wise , so if in doubht i switch off the MCB, and then the main consumer unit breaker

As i say just an non registered , but qualified Electornic & Electrical engineer from the 70's

 

[ericmark]

The question is if the neutral is really a live? I know we class it as live, but we often don't see it as live, and unless we have a borrowed neutral there is unlikely to be a problem. However we are not permitted to work on live circuits, odd but testing not seen as working, so by the rules we need to isolate, and we can only isolate if the neutral is also turned off.

So a double pole RCBO, a RCD or an isolator, this does raise the question without opening the consumer unit, can one identify a double or single pole RCBO? Not sure I could, but technically if double pole it would be OK to isolate at the RCBO, but rare to see double pole MCB's so technically correct, the MCB does not isolate.

However I would be happy turning off the MCB. If I had any, but yes technically it's not isolating.

 

[EFLImpudence]

BS7671 in Table 537.4 re: isolation would seem to disagree with you - and also, by the way, disagree with its own definition.

There's a surprise.

 

[ericmark]

I seem to remember an amendment to 17th edition, but could not find it.

However the live working rules are a HSE thing not wiring regs.

 

[crystal ball]

The only correct way

https://www.screwfix.com/p/kasp-easfit-mcb-safety-lock-off/8195T?tc=ZB5&gad_source=1&gbraid=0AAAAAD8IdPwhFZsoUK2URiJADQKhiLHx3&gclid=CjwKCAjw5qC2BhB8EiwAvqa41k72ozWcywr4Dcpfi0mNHFEmldlfKxwmxRF1aunZ38pd_N6MEF6ixRoCdvcQAvD_BwE&gclsrc=aw.ds

 

[EFLImpudence]

I seem to remember an amendment to 17th edition, but could not find it.

However the live working rules are a HSE thing not wiring regs.

Yes, but 7671 says lots of single-pole devices are suitable for isolation, although the definition is:

 

[foxhole]

I turned off a fuse board to change a light switch for a friend . Still got a shock , incoming mains had live and neutral reversed .