segregation of lighting circuits and rcd protection

[freedomrun]

Domestic PME, 2 lighting cct's (over 2 floors in semi) all circuits other than the lighting cct's are RCD protected to 30mA on a split board CU. Going to install an extractor in the bathroom, just outside the bathroom is a hall light operated by a two way switch that is connected to the lower floor lighting cct, i was thinking about moving the upper lighting circuit that the bathroom lighting is on - to the RCD protected side of the board rather than increase the cost with an RCBO and leave the lower floor lighting with the upper hall light on it where it is (not RCD protected), so if the RCD does trip, the upper hall light will still be working and all lighting on the lower floor. Any deviation from the regs in doing this, any advice please? thanks.

 

[SPECIAL LOCATION]

Domestic PME, 2 lighting cct's (over 2 floors in semi) all circuits other than the lighting cct's are RCD protected to 30mA on a split board CU. Going to install an extractor in the bathroom, just outside the bathroom is a hall light operated by a two way switch that is connected to the lower floor lighting cct, i was thinking about moving the upper lighting circuit that the bathroom lighting is on - to the RCD protected side of the board rather than increase the cost with an RCBO and leave the lower floor lighting with the upper hall light on it where it is (not RCD protected), so if the RCD does trip, the upper hall light will still be working and all lighting on the lower floor. Any deviation from the regs in doing this, any advice please? thanks.

So when the RCD trips you will leave them without SOCKETS AND LIGHTS on one floor???

314.1 (i)

314.1 (iii)

sounds quite inconvenient to me to be unable to plug a table lamp in the bedroom room cuz they are unable to reset the RCD's till the electrician come round in the morning!?

I am honestly amazed that a competent business person cannot factor in around

 

[alpha spark]

Have u done the cu change or has it already been done prior to u arriving I'd be carefull if u have just got there and it's like that. Sounds to me they've tried to put on a rcd and won't have it so they've opted for the easiest route and just put both on mcbs could have (shared neutral) come across it plenty of times so i would advise to test circuit before u alter it

 

[SPECIAL LOCATION]

Have u done the cu change or has it already been done prior to u arriving I'd be carefull if u have just got there and it's like that. Sounds to me they've tried to put on a rcd and won't have it so they've opted for the easiest route and just put both on mcbs could have (shared neutral) come across it plenty of times so i would advise to test circuit before u alter it

No it doesn't!

I think it actually sounds more like a typical 16th edition split load baord...,

Sockets and shower on the RCD side..

all other circuits on the non-RCD side....

So both light circuits are on non-RCD because 16th edition had NO requirement for lights to be RCD protected.

Now a new addition to the light circuit means that circuit needs RCD protection...

But freedomrun doesn't want to pay for an RCBO just wants to move the whole circuit over to the RCD protected side of the board.

:C

 

[alpha spark]

My mistake thought it was a dual split load he was saying

 

[ProDave]

I would bite the bullet and fit an rcbo. A 6A rcbo is part of my standard kit of parts I now carry for such situations. The cost of doing so is little different to the time it would take you to reconfigure the existing board, and it would be a much better solution.

Of course there is the chance of uncovering a borrowed neutral can of worms, but you don't know until you try, or do some testing.

 

[freedomrun]

I previously suggested to the customer about an RCBO replacement for the MCB as this seems the sensible option, the customer says they asked a friend of a friend who knew PART P and it was suggested to them that as the upper landing light was on an isolated circuit, then if the RCD for the entire install did trip, then they would still have ONE light on the upper floor and all lighting on the lower floor and this would satisfy the requirement for segregation of the circuits. The customer is telling me they will not pay for the change of MCB to RCBO or the time taken for me to change / test.

 

[ProDave]

Well the only other suggestion is feed the new fan from an RCD FCU (assuming you are not altering the lighting)

Otherwise walk away and let the cowboys do it if the customer is really that tight. Otherwise it sounds like a lot of grief for not much return.

 

[Doc Hudson]

I previously suggested to the customer about an RCBO replacement for the MCB as this seems the sensible option, the customer says they asked a friend of a friend who knew PART P and it was suggested to them that as the upper landing light was on an isolated circuit, then if the RCD for the entire install did trip, then they would still have ONE light on the upper floor and all lighting on the lower floor and this would satisfy the requirement for segregation of the circuits. The customer is telling me they will not pay for the change of MCB to RCBO or the time taken for me to change / test.

Part P has no relevance on this mater in segregating the circuits, the regulations are not retrospective. As Part P relates to your fan in a bathroom, not the arrangement of the light circuit, the friend of the friend would appear to know very little by the sounds of it.

Doc H.

---------- Post Auto-Merged at 23:37 ---------- Previous post was made at 23:15 ----------

I would bite the bullet and fit an rcbo. A 6A rcbo is part of my standard kit of parts I now carry for such situations. The cost of doing so is little different to the time it would take you to reconfigure the existing board, and it would be a much better solution.Of course there is the chance of uncovering a borrowed neutral can of worms, but you don't know until you try, or do some testing.

For associated debate on the topic of using non-manufactures RCBO's in an existing CU please see this thread:

http://www.talk.electricianforum.co.uk/question-answer-board/19250-using-none-manufactures-parts-consumer-units-re-segregation-lighting-circuits-residual-current-device-bs-en-61008-protection.html

Doc H.

 

[SPECIAL LOCATION]

I previously suggested to the customer about an RCBO replacement for the MCB as this seems the sensible option, the customer says they asked a friend of a friend who knew PART P and it was suggested to them that as the upper landing light was on an isolated circuit, then if the RCD for the entire install did trip, then they would still have ONE light on the upper floor and all lighting on the lower floor and this would satisfy the requirement for segregation of the circuits. The customer is telling me they will not pay for the change of MCB to RCBO or the time taken for me to change / test.

Do you mean the customer says you are too expensive to do the job?

If so ...

just say goodbye and go to the next job...

OR...

are you actually trying to say..

You have started a job.. but you ballsed up the pricing at the start..

and you are trying to get more money out of the customer to do the job properly...

Cuz on the face of it this does sound more like a problem of poor job pricing to start with!

It often happens that an inexperienced electrician under-prices a job then has trouble trying to get a bit more from the customer who clearly will be unhappy about being asked for more money.

Consider:-

1/

If the customer had been told the job was

 

[kme]

Not a lot to add to that.......

The customer doesn`t generally KNOW the rules, and doesn`t want to know them - thats why they employ someone who supposedly does.

If you`d come back to me with an inflated materials bill, cos you`d forgotten something, does that suddenly make it my fault? NO

The joys of being in business, coupled with the necessity for proper design considerations, even if "it is only a bathroom fan".

 

[freedomrun]

Thanks for the advice here, I have'nt started the job yet - the customer is an old boy who used to like doing DIY when he could get about more, since living at this house he has not altered any of the electrical installation, but says if he could do it himself, then he would - but understands any work in the bathroom he could'nt perform now anyway - this has'nt stopped the old boy reading on the internet and asking other people how to go about doing the job and this is where my question comes in as i was'nt sure about moving the MCB over to the RCD side of the board and just wanted some advice here. Correct, most people would'nt care what was done as long as the price was agreed, in this case the customer is a nice old bloke (but very good at telling me what i want to be doing - memories of Harry Enfield sketches flood back !!) just involving himself with every aspect of the work to be done, just can't get enough of it - even calling me up about something he's just read on the internet about the wiring regs, Part P or notes from the ESC. When told about having no lighting in the upper rooms or sockets for lamps if i move the MCB over, i just hear a rant about torches and what were we meant to do before the invention of the light bulb and so on and so on ........... Thanks.

 

[Doc Hudson]

Thanks for the advice here, I have'nt started the job yet - the customer is an old boy who used to like doing DIY when he could get about more, since living at this house he has not altered any of the electrical installation, but says if he could do it himself, then he would - but understands any work in the bathroom he could'nt perform now anyway - this has'nt stopped the old boy reading on the internet and asking other people how to go about doing the job and this is where my question comes in as i was'nt sure about moving the MCB over to the RCD side of the board and just wanted some advice here. Correct, most people would'nt care what was done as long as the price was agreed, in this case the customer is a nice old bloke (but very good at telling me what i want to be doing - memories of Harry Enfield sketches flood back !!) just involving himself with every aspect of the work to be done, just can't get enough of it - even calling me up about something he's just read on the internet about the wiring regs, Part P or notes from the ESC. When told about having no lighting in the upper rooms or sockets for lamps if i move the MCB over, i just hear a rant about torches and what were we meant to do before the invention of the light bulb and so on and so on ........... Thanks.

There are a lot of people like that about, I think it is ultimately a question of what standards do you want to work to. It is almost a bartering exercise, he is trying to knock your price down, you are trying to sell the best product. If he wants to use torches why not just open a window as well and forget the extractor? You will have to decide based upon your knowledge of the particular installation and what you consider the risks and inconvenience will be in the event of a fault. We all know the regulations are open to interpretation and it will be your name confirming compliance with BS7671 & Part P. I think you already have a good overview of the options from the debate on this thread and I don't think there are many other options to consider. Do let us know what the final decision is.

Doc H.

 

[freedomrun]

Will do - if he wants me to continue then it's got to be the RCBO route, after all he has'nt got to put his name to it, only the cheque. Thanks for taking the time to give me some good advice on this subject.