GROUPING

[DAJ]

I have recently installed a new 16 way consumer unit containing 6 x 6a, 5 x 32a and 1 x 40a RCBO's. 6 x light circuits, 5 x socket rings and a cooker outlet (for 5.7kw oven and 4kw hob). I feel competent and I've followed as much spec and calcs as I could find. i have not attempted to cut corners to save time and/or money. this is my home and i wanted to do it properly. I've tested all the circuits, one by one and all on together with no problems - everything worked first time and as it should. I have several questions, so PLEASE be patient...

1) I have split my lounge light circuits in two - thus 2 x 6a RCBO's feed one room. I done this because one of the RCBO's feed a total of 12 x 50w dimmerble halagen spots and the other RCBO 8 x spots (same). I've now been told by an electrician, I should have used 2.5mm and not 1.5mm - is that correct?

2) At the rear of the consumer unit, I have colour coded each cable, or pairs of cables, by taping them together using various coloured insulating tape. For example, I have "grouped", using tape, about 18" of the tails entering the CU. I done this to easily identify each group when connecting them up to the RCBO's and to help those that work on the CU in the future. Again, the electricain has told me that this can cause a fire. true?

3) I have used 10mm cable from the 40a RCBO in the CU to the cooker outlet (about 9m). This will feed a 5.7kw oven and from that, 6mm cable feeding hobs totaling 5kw (dominos). I done this because I thought a 40a RCBO could feed around 13000w. Once agian, the electrician has told be that I've messed up! I should have used 10mm on everything including the feed to the hobs. he also said that a 40a was not enough! True or false?

4) One of the 32a RCBO's at the CU, feeds outside 2 x 2 gang sockets which are RCD protected. He (the electrician) has told me that you should "NEVER" put an RCD on a circuit protected by RCBO's.

5) I installed, from scratch, 3 light circuits and 4 x socket rings (extension, loft conversion and terrace). In doing so, I had to provide a neutral feed to all light switches because I installed X10 light switches. I installed all the switches (20 of them!!!) and they all operated perfectly when commanded to either by switching them on manually or via the computer/mobile phone. the electrician has told me that i could face prosecution for installing neutral feeds to switches!!!!

There are other things he said, but they'll keep for another post. he has told me that the whole lot needs "ripping" out" and doing by a "qualified sparks who knows what hes doing mate". I am so down now. I've spent months and months of research and man hours, not to mention money! I was, and still am, proud of the level of workmanship I have achieved, but now worried that it all may have to be done again. HELP!!

 

[burntwire]

Hi,

The first thing is did you involve building control in this ? How is it all tested ? did you do this yourself too ? just because it works doesnt make it safe.

Do you live in a big house ? the amount of circuits do seem a bit excessive.

1) All these light could have gone on one circuit. cant see why you would need 2.5 unless the cable is covered by insulation

2)Are these taped together in pairs then all as one ? If they were going to cause a fire he should have taken the tape off before he left.

3)Diversty ?

4) Why did you Put RCD sockets on RBO anyway ? altough not dangerous IMO just a nusiance as the RCBO will probably trip first anyway

5)Cant see why no neutrals at switches some old / electrocnic dimmers require them

 

[burntwire]

I just read you message again. I dont blame householders for not knowing about Part P, I ask many of my customers if they have heard bout it and they say no, altough they always know about Corgi and inform me its now GAS SAFE, I think its about time that more Part P advertising is carried out to inform people,

Anyway you say that you feel you are competent, could you prove this in court when your house burns down and the insurance wont pay out ?

Looking at your post and the questions on it I would say your NOT competent

If its your home and you wanted to do it properly why didnt you call an electrician before you started work, many will allow you to work side by side learning as you go whilst supervising you, were not all bad!

I hope that you dont think I am being rude but I wouldnt go and attempt to fly a plane with internet knowledge as altough I might think I understand I think id probably die !!

I would recommend paying an electrician to carry out a Periodic Test & Inspection to see what is really going on, get him to carry out remedial works (maybe between you)

Is it a new extension or an old one thats rewired ?

 

[mikhailfaradayski]

I have recently installed a new 16 way consumer unit containing 6 x 6a, 5 x 32a and 1 x 40a RCBO's. 6 x light circuits, 5 x socket rings and a cooker outlet (for 5.7kw oven and 4kw hob).

Did you realize before you started that the work you were embarking on was notifiable under part P?

I feel competent and I've followed as much spec and calcs as I could find

Where did you look for this info? Do you have a copy of BS7671?

i have not attempted to cut corners to save time and/or money.

But you didn't get a sparky to do it and we've yet to see whether you have splashed out £50 or so pounds to buy a copy of the regs (see above question) so i would say you have.

this is my home and i wanted to do it properly. I've tested all the circuits,

How did you do this, what test equipment did you use?

one by one and all on together with no problems - everything worked first time and as it should.

What tripping times did you get for all of your RCD or RCBOs? Do you know how many values you would expect to get for each device?

I have several questions, so PLEASE be patient...

I have a feeling you are not going to like the answers

1) I have split my lounge light circuits in two - thus 2 x 6a RCBO's feed one room. I done this because one of the RCBO's feed a total of 12 x 50w dimmerble halagen spots and the other RCBO 8 x spots (same). I've now been told by an electrician, I should have used 2.5mm and not 1.5mm - is that correct?

On the face of it, it doesn't sound necessary to use 2.5mm, but maybe the electrician can see some reason why this may have been appropriate. Maybe due to thermal insulation or volt drop? What reason were you given?

2) At the rear of the consumer unit, I have colour coded each cable, or pairs of cables, by taping them together using various coloured insulating tape. For example, I have "grouped", using tape, about 18" of the tails entering the CU. I done this to easily identify each group when connecting them up to the RCBO's and to help those that work on the CU in the future. Again, the electricain has told me that this can cause a fire. true?

Quite possibly, can you post a photo of the cu?

3) I have used 10mm cable from the 40a RCBO in the CU to the cooker outlet (about 9m). This will feed a 5.7kw oven and from that, 6mm cable feeding hobs totaling 5kw (dominos).

what does dominos mean here?

I done this because I thought a 40a RCBO could feed around 13000w. Once agian, the electrician has told be that I've messed up! I should have used 10mm on everything including the feed to the hobs. he also said that a 40a was not enough! True or false?

probably false. Do you understand diversity?

4) One of the 32a RCBO's at the CU, feeds outside 2 x 2 gang sockets which are RCD protected. He (the electrician) has told me that you should "NEVER" put an RCD on a circuit protected by RCBO's.

did he really say exactly that? Could it possible he said some thing like 'its never necessary to have two RCDs of the same rating connected like that'?

5) I installed, from scratch, 3 light circuits and 4 x socket rings (extension, loft conversion and terrace). In doing so, I had to provide a neutral feed to all light switches because I installed X10 light switches. I installed all the switches (20 of them!!!) and they all operated perfectly when commanded to either by switching them on manually or via the computer/mobile phone. the electrician has told me that i could face prosecution for installing neutral feeds to switches!!!!

Again, are you sure thats exactly what he said?

There are other things he said, but they'll keep for another post. he has told me that the whole lot needs "ripping" out" and doing by a "qualified sparks who knows what hes doing mate".

he could be completely or partially correct, difficult to say without looking closely.

I am so down now.

sorry about that

I've spent months and months of research and man hours,

really? What research? At any point in this research, did you find anything to do with part p of the building regs? If you have heard of it, maybe you should have looked into that a bit further before you started

not to mention money! I was, and still am, proud of the level of workmanship I have achieved, but now worried that it all may have to be done again. HELP!!

Sorry to say, but if it turns out that the electrician telling you all this stuff is genuine, it looks like you have wasted a lot of time and money and created your self probably as much work as you have done

 

[skenk]

1) I have split my lounge light circuits in two - thus 2 x 6a RCBO's feed one room. I done this because one of the RCBO's feed a total of 12 x 50w dimmerble halagen spots and the other RCBO 8 x spots (same). I've now been told by an electrician, I should have used 2.5mm and not 1.5mm - is that correct?

2.5mm on a 6A RCBO? No, 1.5mm is more than adequate unless (off the top of my head) completely surrounded by insulation, even then it might be ok.

2) At the rear of the consumer unit, I have colour coded each cable, or pairs of cables, by taping them together using various coloured insulating tape. For example, I have "grouped", using tape, about 18" of the tails entering the CU. I done this to easily identify each group when connecting them up to the RCBO's and to help those that work on the CU in the future. Again, the electrician has told me that this can cause a fire. true?

Can you post a picture?

3) I have used 10mm cable from the 40a RCBO in the CU to the cooker outlet (about 9m). This will feed a 5.7kw oven and from that, 6mm cable feeding hobs totaling 5kw (dominos). I done this because I thought a 40a RCBO could feed around 13000w. Once agian, the electrician has told be that I've messed up! I should have used 10mm on everything including the feed to the hobs. he also said that a 40a was not enough! True or false?

How big is your house? (it is a relevant question) What do the MI's say about electrical connection of the appliances? What kind of hobs are they (ceramic, induction etc) and how many rings? How did you calculate 13kw? 40A may not be adequate for this load. WRT cable size, there is some debate about the sizing of the final connection to cooking appliances but it seems to be generally accepted that if there is no guidance in the MI's then the appliance can be connected with a cable which exceeds the max draw of the appliance but not necessarily as large as the circuit cable. In any case 6mm t&e at 9m length can safely carry 40A, although there may be ambient temperature factor to consider.

4) One of the 32a RCBO's at the CU, feeds outside 2 x 2 gang sockets which are RCD protected. He (the electrician) has told me that you should "NEVER" put an RCD on a circuit protected by RCBO's.

If anything it makes the installation a tiny bit safer because if one RCD was faulty there would be a back-up but it is generally seen at the least as unnecessary and pointless, there are discrimination problems and it can increases the inconvenience in the event of a fault/faulty RCD. Ideal solution would be having a protected/surface run/deeply buried cable on the non-rcd side and have the RCD at the outdoor socket and but simply changing the outdoor sockets for normal weatherproof ones would regularise the setup and satisfy any departures for the regs relating to discrimination and inconvenience. I'm sure there a few threads on here where it has been discussed.

5) I installed, from scratch, 3 light circuits and 4 x socket rings (extension, loft conversion and terrace). In doing so, I had to provide a neutral feed to all light switches because I installed X10 light switches. I installed all the switches (20 of them!!!) and they all operated perfectly when commanded to either by switching them on manually or via the computer/mobile phone. the electrician has told me that i could face prosecution for installing neutral feeds to switches!!!!

There are problems if you have data cables alongside mains or sharing the same enclosures. There is absolutely nothing wrong with having neutrals at switch location and for an electrician to tell you otherwise suggests he must be a con merchant or dangerously incompetent.

There are other things he said, but they'll keep for another post. he has told me that the whole lot needs "ripping" out" and doing by a "qualified sparks who knows what hes doing mate". I am so down now. I've spent months and months of research and man hours, not to mention money! I was, and still am, proud of the level of workmanship I have achieved, but now worried that it all may have to be done again. HELP!!

If you had done much research on here you would have found many people who are told to involve an electrician from the start, or notify building control and find out their procedure for DIY rewire attempts. You have not done this . . . WHY!?

What were the other things he said?

Lets have some pictures of your work so we can assess your workmanship.

 

[DetlefSchmitz]

What was the actual reason for this electrician to appear on the scene? The answer to this may well affect any answers given.

 

[xr4x4]

It's all gone quiet....! Funny that.

 

[LearningSpark]

I guess as usual the OP has done all this work then contacted an electrician to come and sign off his work for LABC. It aint going to happen.

 

[ban-all-sheds]

I've tested all the circuits, one by one and all on together with no problems

Could you scan or photograph your schedule of test results and post it?

I've now been told by an electrician, I should have used 2.5mm and not 1.5mm - is that correct?

I feel competent

- that means you know how to design circuits, know what the current carrying capacity of your cables are given their installation method, grouping and other de-rating factors, what the voltage drop will be and therefore you know whether you should have used 1.5mm² or 2.5mm².

2) At the rear of the consumer unit, I have colour coded each cable, or pairs of cables, by taping them together using various coloured insulating tape. For example, I have "grouped", using tape, about 18" of the tails entering the CU. I done this to easily identify each group when connecting them up to the RCBO's and to help those that work on the CU in the future. Again, the electricain has told me that this can cause a fire. true?

I feel competent

- that means you would have applied the necessary grouping factors when working out the cable sizes.

Once agian, the electrician has told be that I've messed up! I should have used 10mm on everything including the feed to the hobs. he also said that a 40a was not enough! True or false?

I feel competent

- what was your design load allowing for diversity?

the electrician has told me that i could face prosecution for installing neutral feeds to switches!!!!

I was, and still am, proud of the level of workmanship I have achieved, but now worried that it all may have to be done again. HELP!!

I feel competent

- that means you must know if it's any good.

 

[DAJ]

woooooooooooooooooooooooo! Slow down guys, calm down chaps! Too many answers AND questions all at the same time to respond! Most not helpful and insulting to say the least! I haven't raped anyone or eaten children!

As soon as I have time, I'll reply !

 

[DAJ]

Hi,

The first thing is did you involve building control in this ? How is it all tested ? did you do this yourself too ? just because it works doesnt make it safe.

Do you live in a big house ? the amount of circuits do seem a bit excessive.

1) All these light could have gone on one circuit. cant see why you would need 2.5 unless the cable is covered by insulation

2)Are these taped together in pairs then all as one ? If they were going to cause a fire he should have taken the tape off before he left.

3)Diversty ?

4) Why did you Put RCD sockets on RBO anyway ? altough not dangerous IMO just a nusiance as the RCBO will probably trip first anyway

5)Cant see why no neutrals at switches some old / electrocnic dimmers require them

1 - I thought the max on one 6a RCBO was 1200w, thats why!

2. The last 18" of each pair going into the CU are taped - not bundled or grouped in any way!

3. can't dance!

4. I had already installed the RCD outlet around 8 months prior to the new CU

5. most X10 (if not all) control modules need a N feed

Thanks for your help!

 

[xr4x4]

woooooooooooooooooooooooo! Slow down guys, calm down chaps! Too many answers AND questions all at the same time to respond! Most not helpful and insulting to say the least! I haven't raped anyone or eaten children!

As soon as I have time, I'll reply !

Sorry, aren't you the one asking for help?

Your not really in the position to start making the rules.

 

[DAJ]

I have recently installed a new 16 way consumer unit containing 6 x 6a, 5 x 32a and 1 x 40a RCBO's. 6 x light circuits, 5 x socket rings and a cooker outlet (for 5.7kw oven and 4kw hob).

Did you realize before you started that the work you were embarking on was notifiable under part P?

I feel competent and I've followed as much spec and calcs as I could find

Where did you look for this info? Do you have a copy of BS7671?

i have not attempted to cut corners to save time and/or money.

But you didn't get a sparky to do it and we've yet to see whether you have splashed out £50 or so pounds to buy a copy of the regs (see above question) so i would say you have.

this is my home and i wanted to do it properly. I've tested all the circuits,

How did you do this, what test equipment did you use?

one by one and all on together with no problems - everything worked first time and as it should.

What tripping times did you get for all of your RCD or RCBOs? Do you know how many values you would expect to get for each device?

I have several questions, so PLEASE be patient...

I have a feeling you are not going to like the answers

1) I have split my lounge light circuits in two - thus 2 x 6a RCBO's feed one room. I done this because one of the RCBO's feed a total of 12 x 50w dimmerble halagen spots and the other RCBO 8 x spots (same). I've now been told by an electrician, I should have used 2.5mm and not 1.5mm - is that correct?

On the face of it, it doesn't sound necessary to use 2.5mm, but maybe the electrician can see some reason why this may have been appropriate. Maybe due to thermal insulation or volt drop? What reason were you given?

2) At the rear of the consumer unit, I have colour coded each cable, or pairs of cables, by taping them together using various coloured insulating tape. For example, I have "grouped", using tape, about 18" of the tails entering the CU. I done this to easily identify each group when connecting them up to the RCBO's and to help those that work on the CU in the future. Again, the electricain has told me that this can cause a fire. true?

Quite possibly, can you post a photo of the cu?

3) I have used 10mm cable from the 40a RCBO in the CU to the cooker outlet (about 9m). This will feed a 5.7kw oven and from that, 6mm cable feeding hobs totaling 5kw (dominos).

what does dominos mean here?

I done this because I thought a 40a RCBO could feed around 13000w. Once agian, the electrician has told be that I've messed up! I should have used 10mm on everything including the feed to the hobs. he also said that a 40a was not enough! True or false?

probably false. Do you understand diversity?

4) One of the 32a RCBO's at the CU, feeds outside 2 x 2 gang sockets which are RCD protected. He (the electrician) has told me that you should "NEVER" put an RCD on a circuit protected by RCBO's.

did he really say exactly that? Could it possible he said some thing like 'its never necessary to have two RCDs of the same rating connected like that'?

5) I installed, from scratch, 3 light circuits and 4 x socket rings (extension, loft conversion and terrace). In doing so, I had to provide a neutral feed to all light switches because I installed X10 light switches. I installed all the switches (20 of them!!!) and they all operated perfectly when commanded to either by switching them on manually or via the computer/mobile phone. the electrician has told me that i could face prosecution for installing neutral feeds to switches!!!!

Again, are you sure thats exactly what he said?

There are other things he said, but they'll keep for another post. he has told me that the whole lot needs "ripping" out" and doing by a "qualified sparks who knows what hes doing mate".

he could be completely or partially correct, difficult to say without looking closely.

I am so down now.

sorry about that

I've spent months and months of research and man hours,

really? What research? At any point in this research, did you find anything to do with part p of the building regs? If you have heard of it, maybe you should have looked into that a bit further before you started

not to mention money! I was, and still am, proud of the level of workmanship I have achieved, but now worried that it all may have to be done again. HELP!!

Sorry to say, but if it turns out that the electrician telling you all this stuff is genuine, it looks like you have wasted a lot of time and money and created your self probably as much work as you have done

The "electrician" turns out to be a roofer who does electrcal work for a local builder, found out this afternoon. Not you is it? Oh - and I am competent !

 

[DAJ]

woooooooooooooooooooooooo! Slow down guys, calm down chaps! Too many answers AND questions all at the same time to respond! Most not helpful and insulting to say the least! I haven't raped anyone or eaten children!

As soon as I have time, I'll reply !

Sorry, aren't you the one asking for help?

Your not really in the position to start making the rules.

YOU CALL THIS LOT HELP - YOU'RE JOKING MATE.

I wont be on here again - a forum is for helping and advising people, not for jobsworths spouting off

 

[xr4x4]

Bye then.