Dual RCD

[Mike P]

And 9 times out of 10 you can't split the lighting circuits due to a shared neutral on the landing light.

The dual rcd boards only comply on a new install where they are loaded correctly.

I totally agree that they should have been phased out by Amd2. Maybe we should all wait for the consultation on Amd3 and push for it ??

It would still be an issue with shared neutrals and individual RCBOs

 

[mort2376]

It would still be an issue with shared neutrals and individual RCBOs

True as they would have to be on the same rcbo. But at least you can have lamps plugged in and on with an rcbo board.

 

[Badger]

I forget how many circuits we have but I know we have 7 CUs

Why so many cu s mind you thinking about it I have 4 greenhouse mini, shed, main board, pond mini

 

[mickey c]

And 9 times out of 10 you can't split the lighting circuits due to a shared neutral on the landing light.

The dual rcd boards only comply on a new install where they are loaded correctly.

I totally agree that they should have been phased out by Amd2. Maybe we should all wait for the consultation on Amd3 and push for it ??

Shared neutrals are dangerous. How would you certificate your work?? Put all the lighting on one circuit? They should be split before you attempt to change the board.

 

[mort2376]

Shared neutrals are dangerous. How would you certificate your work?? Put all the lighting on one circuit? They should be split before you attempt to change the board

If the homeowner won't pay and doesn't want the disruption of new wiring then you have to put them on the same rcbo.

It is acceptable as its the only safe thing to do.

I went to quote a cu change last week.

It had 3 circuits. Lights, sockets and cooker.

I shook my head and said 5k to change the board and you get a free rewire included

 

[Murdoch]

Shared neutrals are dangerous. How would you certificate your work?? Put all the lighting on one circuit? They should be split before you attempt to change the board.

Not sure I agree with this.

Nobody can tell a homeowner that they must fix a borrowed neutral which is so prevalent on mid 1960’s to mid 1970’s properties.

Nothing wrong with all lights being on a single RCBO

 

[Sparksfly]

Not sure I agree with this.

Nobody can tell a homeowner that they must fix a borrowed neutral which is so prevalent on mid 1960’s to mid 1970’s properties.

Nothing wrong with all lights being on a single RCBO

I agree and nothing wrong having light ccts with borrowed neutrals on a dual RCD board so long as it is on the same RCD.

 

[Andy™]

I agree and nothing wrong having light ccts with borrowed neutrals on a dual RCD board so long as it is on the same RCD.

apart from the minor issue that you can get an electric shock from the neutral of an 'isolated' circuit once they are parted. anyone who thinks this is acceptable needs to go back to plumbing wheret he worst thatll happen is you get wet rather than dead

 

[Murdoch]

I agree and nothing wrong having light ccts with borrowed neutrals on a dual RCD board so long as it is on the same RCD.

Not sure I agree with you. Borrowed neutral lighting MUST have both lives in the same MCB

 

[Sharpend]

I agree and nothing wrong having light ccts with borrowed neutrals on a dual RCD board so long as it is on the same RCD.

This really is wrong on many levels.
A little knowledge is dangerous springs to mind.

 

[SPECIAL LOCATION]

I agree and nothing wrong having light ccts with borrowed neutrals on a dual RCD board so long as it is on the same RCD.

That is complete and utter B****cks....!!

This would suggest you have never actual read any of BS7671...

And certainly have no knowledge of the concept that ALL circuits MUST be independent of each other...
AND you must NOT permit the same piece of cable to be energised from multiple protective devices..

May I politely suggest you go back and read items such as:-

314.4 (pg 56 current regs)
even in a multicore cable its a NO-NO!
521.8.2 (pg 140 current regs)

Classic example of how the internet can be a dangerous place for getting info when non-competent persons can post incorrect advice!!

 

[apprentice87]

Nobody can tell a homeowner that they must fix a borrowed neutral which is so prevalent on mid 1960’s to mid 1970’s properties

How do you work that out?? If you took your car to a garage and they said you needed new brake pads, [but you did not like the price] they would not fit wooden ones just to keep you happy. They would just refuse to do the work.

john..

 

[PaulieN]

apart from the minor issue that you can get an electric shock from the neutral of an 'isolated' circuit once they are parted. anyone who thinks this is acceptable needs to go back to plumbing wheret he worst thatll happen is you get wet rather than dead

Anyone who thinks borrowed neutrals are OK should be taken out and shot at dawn in my book. Back in the day I had a very unpleasant tickle or two due to the buggers!!

As for plumbing, let a cretin at it and the worst thing that can happen isn't puddles of water, it's a demolished house after it's exploded!

 

[Sparksfly]

Not sure I agree with you. Borrowed neutral lighting MUST have both lives in the same MCB

Opps Sorry.... Yes and same MCB.......signed very wetpants !

 

[Sparksfly]

That is complete and utter B****cks....!!

This would suggest you have never actual read any of BS7671...

And certainly have no knowledge of the concept that ALL circuits MUST be independent of each other...
AND you must NOT permit the same piece of cable to be energised from multiple protective devices..

May I politely suggest you go back and read items such as:-

314.4 (pg 56 current regs)
even in a multicore cable its a NO-NO!
521.8.2 (pg 140 current regs)

Classic example of how the internet can be a dangerous place for getting info when non-competent persons can post incorrect advice!!

Thank you for the info....will look it up once I get the shrink wrap off the new BBB.

 

[mort2376]

314.4 (pg 56 current regs)
even in a multicore cable its a NO-NO!

Not sure I agree with this. I have seen plenty of multicore swa cables supplying different circuits.

If you followed the BBB to the letter then the upstairs and downstairs 2 way switches need a lovely yellow sticker on if supplied from 2 circuits and I don't see that happening.

 

[Murdoch]

If you followed the BBB to the letter then the upstairs and downstairs 2 way switches need a lovely yellow sticker on if supplied from 2 circuits and I don't see that happening.

Yes, nonsense BUT in a 3 phase install lighting split over phases could be an issue BUT somebody tampering with this shouldn’t need a warning

A bit like the now obsolete dual colour cable colour warning labels

 

[mort2376]

A bit like the now obsolete dual colour cable colour warning labels

I will still be fitting them on 3phase boards.

Even now if I'm doing a board replacement it's easy to get distracted and all blues goes to neutral.

It's a good job that most neutral bars allow you to loop the cable to leave slack on them

 

[Andy™]

If you followed the BBB to the letter then the upstairs and downstairs 2 way switches need a lovely yellow sticker on if supplied from 2 circuits and I don't see that happening.

there is no reg in BS7671 stating this

 

[Andy™]

Not sure I agree with this. I have seen plenty of multicore swa cables supplying different circuits.

521.7 does allow 2 or more circuits within the same cable providing certain conditions are met