Supply for Combi Boiler - RCD required ?

[Dave OCD]

Allright chaps

I have to connect a new Combi this Saturday morning, intending to fit a 3 amp fused switched FCU and take the supply off a handy socket [about 2 feet away and on a RFC not a spur]

The consumer unit is an old MEM with cartridge fuses and there's no RCD, [TNCS system with Ze of 0.14]
Now assuming the owner doesn't want a new CU [yet anyway] would you be happy to connect up as is or would you fit an RCD spur ?
I have an opinion but just wondered what other people might think ?

 

[Darkwood]

What do the manufacturers guidelines say about the electrical requirements?

 

[LankyWill]

i would just fit a standard spur, 3A wont cause too much damage

 

[Dave OCD]

What do the manufacturers guidelines say about the electrical requirements?

Just double pole isolation and 3 amp fuse, no mention of RCD.

 

[Leesparkykent]

I wouldn't worry about it as long as the installation method of the spur you are putting in doesn't require it.

 

[Dave OCD]

i would just fit a standard spur, 3A wont cause too much damage

Well in the event of a fault it'll certainly blow pretty fast Will.

 

[Pete999]

If you are that concerned put a RCD fused spur in £17 from Screwfix I think

 

[Dave OCD]

I wouldn't worry about it as long as the installation method of the spur you are putting in doesn't require it.

Exactly my thoughts Lee. :smiley2:

 

[Leesparkykent]

Exactly my thoughts Lee. :smiley2:

Any way from next Wednesday you only have to take into account of the manufacturer's relevant instructions, if any. Haha :clap:

 

[NoSparks]

My understanding is that any NEW work, which would include this, was required to comply with Current Regs. The regs only require that cable burried in walls etc be protected by an RCD, specifically surface wireing is not required to be RCD protected. so will there be any new wire passing through walls?

 

[telectrix]

My understanding is that any NEW work, which would include this, was required to comply with Current Regs. The regs only require that cable burried in walls etc be protected by an RCD, specifically surface wireing is not required to be RCD protected. so will there be any new wire passing through walls?

not quite right. passing through walls don't need RCD. buried in the plaster < 2" deep does.

 

[Dave OCD]

My understanding is that any NEW work, which would include this, was required to comply with Current Regs. The regs only require that cable burried in walls etc be protected by an RCD, specifically surface wireing is not required to be RCD protected. so will there be any new wire passing through walls?

Not in this case, it'll be about 2 feet of 0.75mm H/R flex from a fused spur right next to an existing socket.

 

[Redvanman]

is the cable to the stat buried

 

[NoSparks]

My understanding is that any NEW work, which would include this, was required to comply with Current Regs. The regs only require that cable burried in walls etc be protected by an RCD, specifically surface wireing is not required to be RCD protected. so will there be any new wire passing through walls?

Well you tel that to my NICEIC inspector! In fact maybe the word "buried" might have more exactly expressed what I ment.

 

[NoSparks]

not quite right. passing through walls don't need RCD. buried in the plaster < 2" deep does.

So in that case an RCD is not strictly needed, but of course you will have checked that the supplementary bonding that was required by the previous standards to which the boiler was first installed are present!!! The problem being that if an earth fault developed then it would be to the boiler which is connected to the metal work of the water and the gas and these cannot be allowed to become live. So in the end it's your decision which way to go.

 

[Leesparkykent]

So in that case an RCD is not strictly needed, but of course you will have checked that the supplementary bonding that was required by the previous standards to which the boiler was first installed are present!!! The problem being that if an earth fault developed then it would be to the boiler which is connected to the metal work of the water and the gas and these cannot be allowed to become live. So in the end it's your decision which way to go.

So everything has to be RCD protected in your book then?

 

[NoSparks]

So everything has to be RCD protected in your book then?

That is too sweeping. There are exceptions as we all know but discussion of those is outside the OP.

 

[Dave OCD]

Well it's all done, and with a Zs at the socket right next to my new fused spur of 0.28 and a 3 amp fuse in said FCU I'll sleep soundly even though there isn't currently an RCD.
In reply to the other questions there are 10mm main bonds to both gas and water and the room stat is wireless RF, did that this morning as well.

 

[Deleted member 26818]

Might require 30mA RCD protection, if the Combi is in a bathroom.
30mA RCD protection is an acceptable method of providing additional protection for cables concealed in walls, as long as the cables are in prescribed zones.

 

[Dave OCD]

Had that been the case then I would definitely have fitted an RCD but this one was in a kitchen.

 

[atm84]

I think you are all missing the point. As he is altering/ making an addition to a circuit then that circuit must comply with 17th edition regulations. As the latest amendment calls for all circuits in a domestic property to be protected by rcd then and rcd IS required.

 

[atm84]

Even if he was wiring to the 2nd amendment, if part of the circuit was buried in the wall, at a depth less than 50mm (which is highly likely) then again an rcd should be fitted as he is making alterations to an existing circuit.

 

[Leesparkykent]

I think you are all missing the point. As he is altering/ making an addition to a circuit then that circuit must comply with 17th edition regulations. As the latest amendment calls for all circuits in a domestic property to be protected by rcd then and rcd IS required.

If the installation method,location of the wiring/switched fused spur taken of the existing circuit doesn't require 30ma RCD protection then it doesn't require it.

 

[atm84]

Well of course if to the 2nd amendment. Like my post it would need to comply with the latest regs. The latest amendment which came into effect on 1 July all circuits in a domestic installation must be protected by rcd.

 

[Leesparkykent]

Well of course if to the 2nd amendment. Like my post it would need to comply with the latest regs. The latest amendment which came into effect on 1 July all circuits in a domestic installation must be protected by rcd.

Not true, who told you that?

 

[Deleted member 26818]

The Regulations only require certain circuits of special locations to be provided with RCD protection.
Circuits such as those of a location containing a bath or shower, circuits supplying socket-outlets in Agricultural/Horticultural installation, etc.

 

[atm84]

Not true, who told you that?

The IET Wiring Matters publication. I'll find it and upload or take a picture.

 

[Leesparkykent]

The IET Wiring Matters publication. I'll find it and upload or take a picture.

Cool. It's not correct though.

 

[Midwest]

Think he would be correct in a domestic property if; was installed in metal earthed conduit or swa, not buried in walls less than 50mm, not in a special location or a socket outlet (unless dedicated socket, i.e. for medical equipement, as long as first bit was complied with and not risk assessed). Can't think of anymore exceptions? So RCD all the way, but agree with you Leysparkykent, but atm84 you kinda of right but for the wrong reasons.

 

[Dave OCD]

The job was completed in June, and on my advice the owner has now requested me to install a 17th edition CU before tenants move in at the end of the month, glad I didn't waste money on an RCD FCU now.
[The new board will NOT be made of steel by the way :laugh3:]

 

[Midwest]

Why not, not regs, just curious?

 

[Midwest]

Not many plastic ones left. And not many metal ones available!

 

[Dave OCD]

Only because you don't have to until Jan 1st, it'll be easier and quicker [tight for space] and done properly I'm confident it won't catch fire. :wink_smile:

 

[andyb]

Only because you don't have to until Jan 1st, it'll be easier and quicker [tight for space] and done properly I'm confident it won't catch fire. :wink_smile:

I've been fitting them for a while now. Although it's not compulsory until January it's in the regs now.
You may be confident of your work, but what if a component broke down and caused a fire, you may find yourself explaining why you chose to ignore the advice of the IET boffins on this and trying to prove that you know better.

 

[Dave OCD]

I understand what you're saying Andy, but if we're going in to legal scenarios you said it yourself - it's not compulsory yet.
Honestly I must have installed 300+ dual RCD boards and haven't had any issues yet, and although made of insulating material I don't fit crap.

 

[atm84]

Cool. It's not correct though.

Sorry my mistake. I've just read the Wiring Matters from the IET regarding amendment three and the supervised or skilled person has been removed meaning that all installations require rcd where necessary. You used to be able to omit in some scenarios if the installation was under the supervision of a skilled or instructed person.

 

[Deleted member 26818]

The skilled or instructed persons exemption applied to socket-outlets being used by ordinary persons whilst supervised, and for cables concealed in walls.
The requirement now is to provide RCD protection for all socket-outlets intended for general use, and for cables concealed in walls run in prescribed zones and not provided with another acceptable method of additional protection.