RCD Protection and cable chasing

[jonnyb1985]

Hi everyone!

I've just moved into a house and for aesthetic purpose, I want to chase a load of the conduit/trunking that is mounted on the walls into the plaster. I've no problem with the work itself, per se: got my oval trunking, know the circuit, etc. My problem is with the regulations.

Looking at the paperwork for the house, I've got the electrical installation certificate from 2007. My major issue is that it appears that my circuits upstairs are not RCD protected for some reason (I guess the regs were different then - certificate indicated BS7671 Part 2 as amended to 2002 with no departures).

Because the plaster is obviously not 50mm deep and because I wouldn't think I'm competent to install the earthed shielding, I think (though I'd appreciate being corrected!) that I would be disallowed from burying the cable in the plaster in this way even if it is in the safe zones. My question is really what to do next in practical terms - I'm not sure I can chase 50 mm into the brickwork beneath the plaster (though will if I have to!). Can/Should I get an RCD installed for the upstairs circuits? Is it going to cost me an arm and a leg (so I'm prepared for the quotes!)

Cheers,

Jon

 

[Zeespark]

Is your board 16th Edition? if so, bury the cables with your oval conduit, and replaced the MCB with an RCBO.

AndyGuinness

 

[Lillpete]

Technically yes you should have the circuit RCD protected either via an RCBO or via a separate RCD nect to the CCU, this would be the best course of action as it would make your installation safer and would meet regulations.

Whisper:: but realistically who would know that the cables weren't chased in all along if you didn't show them the original Cert :innocent

 

[jonnyb1985]

Thanks for the reply, Andy. So that I can be sure, how will I know if my board is 16th Edition? I'd have thought it was based on the date, but I don't like to assume! Also, I'm guessing I need a qualified electrician for the swap - any idea how much it'll cost?

 

[Lillpete]

RCD'ing shouldn't cost much, I would say a couple of hours labour to install and test the RCD plus sign it off plus

 

[Robin Spark]

Hi Johnny,

I think you might be best getting a sparky in to look at the consumer unit and the configuration of your circuits as you might not know if there are any interconnected ciruits which once you have changed from mcbs to rcbos will cause the rcbo to trip.

Also once you have finished burying the cables and its all plastered then get the sparky back to test the circuits to make sure everything is safe so you have peace of mind for your new house and family.

 

[jonnyb1985]

Technically yes you should have the circuit RCD protected either via an RCBO or via a separate RCD nect to the CCU, this would be the best course of action as it would make your installation safer and would meet regulations.Whisper:: but realistically who would know that the cables weren't chased in all along if you didn't show them the original Cert :innocent

I know - I'm just aware of my limits and don't want to do something dangerous! Similarly, don't want to pay a lot of money (buying a house wasn't easy!) if I don't need to, hence asking for the advice. I assume when you are talking about changing the MCBs for RCBOs, you mean actually changing the blocks on the board?

Thanks for the quick replies

 

[Robin Spark]

Technically yes you should have the circuit RCD protected either via an RCBO or via a separate RCD nect to the CCU, this would be the best course of action as it would make your installation safer and would meet regulations.Whisper:: but realistically who would know that the cables weren't chased in all along if you didn't show them the original Cert :innocent

Tut tut Lillpete, you shouldnt be whispering bad advice on this forum that is contrary to the regulations that we have to work to, and also dont forget the certificates were probably photocopied and records made by solicitors during the house purchase and if done by a Part P spark he would still have records as well.

---------- Post Auto-Merged at 22:13 ---------- Previous post was made at 22:03 ----------

I know - I'm just aware of my limits and don't want to do something dangerous! Similarly, don't want to pay a lot of money (buying a house wasn't easy!) if I don't need to, hence asking for the advice. I assume when you are talking about changing the MCBs for RCBOs, you mean actually changing the blocks on the board?Thanks for the quick replies

Johnny, with all due respect, you cannot just go changing mcb's to rcbo's without knowing what you are doing and being able to do the appropriate testing so best advice is

1. get a sparky to check things over before you start

2. He will advise you on anything required and might be best at this stage to change your protective devices and do some tests.

3. Do all your chasing in and putting your cables in capping or oval trunking (are you recessing the boxes as well?)

4. Sparky, might want to come and have a quick look before you plaster.

5. Get your plasterer in unless you are doing it yourself.

6. Get sparky back who can do final tests and give a cert to say what he has done and that your ciruits have tested all ok.

 

[steptoe]

where abouts are you Johnny?

someone close to you may be able to help you out here.

 

[jonnyb1985]

Johnny, with all due respect, you cannot just go changing mcb's to rcbo's without knowing what you are doing and being able to do the appropriate testing so best advice is

Oh Heavens, no, of course I can't! Would never dream of touching the boxes - I just literally wondered what was being suggested!

I've got the names of the guys who did the original installation, will give them a bell in the morning. I literally have no-one who can recommend an electrician to me, so that's as good a place to start as any. But as I don't know this guy, I like to be aware of what might be suggested so that I can keep track of what's being suggested.

I just need to move somewhat swiftly - these rooms don't have heating and I need the plastering done before the heating goes in...and it's winter! So don't want to be slowed down by ignorance, but don't want to break the law either

---------- Post Auto-Merged at 22:20 ---------- Previous post was made at 22:19 ----------

where abouts are you Johnny?someone close to you may be able to help you out here.

Bristol

 

[steptoe]

have a look here

 

[SLIPSHOD & SLAPDASH]

RCD'ing shouldn't cost much, I would say a couple of hours labour to install and test the RCD plus sign it off plus

 

[jonnyb1985]

Thanks steptoe - have pinged off a mail to Inline Electrical, who seem to be nearest. The guy who did the original install has come back with

 

[SLIPSHOD & SLAPDASH]

Thanks steptoe - have pinged off a mail to Inline Electrical, who seem to be nearest. The guy who did the original install has come back with

 

[jonnyb1985]

three

 

[SLIPSHOD & SLAPDASH]

Do you know what make the consumer unit is ?

 

[jonnyb1985]

Do you know what make the consumer unit is ?

Unit says MEM Memera 2000 AD

 

[steptoe]

Wylex MCBs fit, will RCBOs fit too?

 

[SLIPSHOD & SLAPDASH]

I have never fitted a Memera board & rarely work on them. I have a feeling only there own make fits and thats obsolete ? I will have a Google now

---------- Post Auto-Merged at 23:25 ---------- Previous post was made at 23:15 ----------

Ok, i was correct earlier that the Memera AD consumer units use Memshield2 'pod' conversions for RCBO's. These are probably the most expensive RCBO'S around and they are now obsolete as the Memshield 3 is now out and is not compatible. They are however Wylex compatible and you can get numerous cheap RCBO replacements, a forum sponsor sells some for around

 

[jonnyb1985]

I don't know if it makes any difference, but the current MCBs appear to be branded Eaton.

Thanks everso much for your help with all of this.