Alterations on old rewireable consumer unit

[fall-apart-dave]

Ah sorry misread thought you were taking 6mm to the sockets! Though still overkill if its 2.5mm supplying the ring.

 

[Noob2013]

Yeah that was just to supply the RCD then existing 2.5mm from the rcd to sockets lol

May even go for 4mm instead.

 

[Risteard]

The regs say you can't make it WORSE (got them open in front of me)

LOL. Which Regulation states that?

 

[fall-apart-dave]

LOL. Which Regulation states that?

It doesn't say that verbatum. I now don't have the regs in front of me, but something along the lines of serviceable pre-existing installations do not need to be brought up to modern standards (such as red & black cable, old fuse boards etc), new circuits have to be up to spec but additions to existing circuits need only ensure earth impedance, fault and short circuit current etc are within limits, bonding arrangements are correct etc. So in this case, adding to an existing ring needs no consumer unit change, nor (technically) the addition of an RCD. Thats not to say an RCD should not be fitted (you need one really), my point here is that to satisfy regs you need only install one if there's a new circuit going in, not if you are adding to an existing one.
Or, to summarise, you can't leave an existing installation in a worse state (by this I mean for complying to the regs) but you do not have to rip out and replace old stuff just because it does not comply with current regs.
A point to note here is also that the current 17th edition regs are not statutory anyway, they are a guideline. Hope that clears up what I meant..?

 

[telectrix]

what you have just said about existing installation not having to be brought up to current regs. is true, but any work that you do has to be to current regs. i.e even if existing sockets have not got RCD protection, then any that you fit must comply with current edition of BS7671. i.e. RCD protected id required by current regs.

 

[Leesparkykent]

As above reg 134.2.2 BYB and might be worthwhile reading the note from the HSE on page 11.

 

[richy3333]

A point to note here is also that the current 17th edition regs are not statutory anyway, they are a guideline. Hope that clears up what I meant..?

The 'regs' have never been Statutory (capital S) and your statement above puts at variance your earlier post when using words like 'legal'.
To be honest it's hard to give the OP a definitive answer unless the installation method is known.

 

[fall-apart-dave]

what you have just said about existing installation not having to be brought up to current regs. is true, but any work that you do has to be to current regs. i.e even if existing sockets have not got RCD protection, then any that you fit must comply with current edition of BS7671. i.e. RCD protected id required by current regs.

Yeah, work done has to be within regs, but this very scenario came up while I did my 17th edition, I'm almost certain that the instructor said the correct thing to do (within the law, not the *best* thing to do) is to do your work (the sockets) to regs, but altering the existing wiring to modern regs is not required. Though in fairness we were discussing putting sockets at daft heights rather than RCDs on an existing commercial radial (a job I have booked in for later) but I'm sure as I said the consensus was addition of RCD was not required but *should* be done, but in the event it was not installed, it should be clearly documented as such. However, it's a moot point, in really-real world an RCD should be there, and I bow to your experience, I could well be wrong. I am just a noob!

 

[fall-apart-dave]

The 'regs' have never been Statutory (capital S) and your statement above puts at variance your earlier post when using words like 'legal'.
To be honest it's hard to give the OP a definitive answer unless the installation method is known.

Point taken, though capital S or not is just being a pedant. I am using my phone with autocapitalisation and I just didn't bother hitting "shift" while typing. Lets not get bogged down in pettiness, I used the word "legal" rather than "best fit complient with regulations but not necessarily in line with best practice" - it was less of a mouthful. But thank you for your correction nonetheless, I shall try and be more concise and keep an eye on my capital letters in future. *mwah* ---

 

[Leesparkykent]

Yeah, work done has to be within regs, but this very scenario came up while I did my 17th edition, I'm almost certain that the instructor said the correct thing to do (within the law, not the *best* thing to do) is to do your work (the sockets) to regs, but altering the existing wiring to modern regs is not required. Though in fairness we were discussing putting sockets at daft heights rather than RCDs on an existing commercial radial (a job I have booked in for later) but I'm sure as I said the consensus was addition of RCD was not required but *should* be done, but in the event it was not installed, it should be clearly documented as such. However, it's a moot point, in really-real world an RCD should be there, and I bow to your experience, I could well be wrong. I am just a noob!

A departure from bs7671 is something that doesn't strictly comply but offers at least the same level of safety as compliance. If the socket was installed for a specific piece of equipment then it would have to be labelled as such to omit RCD protection but also the installation method would have an impact on this.. For example T&E burried in a wall at a depth of less than 50mm. Again you could omit RCD protection in an installation other than in a dwelling for the new sockets your installing if you produce a documented risk assessment and couple it with the installation/minor works certificate but you being the designer, inspector and tester would have to have a very good reason for the lack of RCD protection especially if something happened and you found yourself in front of a judge. As above the installation method would also have a bearing on this as other regs have to be considered. Since the introduction of Amendment 3 the old get out of jail free card for the omission of RCD protection if it was under the supervision of a skilled or instructed person is no longer an option as the definition of skilled and instructed was being abused.

 

[davesparks]

Ah sorry misread thought you were taking 6mm to the sockets! Though still overkill if its 2.5mm supplying the ring.

Not overkill at all

 

[fall-apart-dave]

A departure from bs7671 is something that doesn't strictly comply but offers at least the same level of safety as compliance. If the socket was installed for a specific piece of equipment then it would have to be labelled as such to omit RCD protection but also the installation method would have an impact on this.. For example T&E burried in a wall at a depth of less than 50mm. Again you could omit RCD protection in an installation other than in a dwelling for the new sockets your installing if you produce a documented risk assessment and couple it with the installation/minor works certificate but you being the designer, inspector and tester would have to have a very good reason for the lack of RCD protection especially if something happened and you found yourself in front of a judge. As above the installation method would also have a bearing on this as other regs have to be considered. Since the introduction of Amendment 3 the old get out of jail free card for the omission of RCD protection if it was under the supervision of a skilled or instructed person is no longer an option as the definition of skilled and instructed was being abused.

Ah, that there is the difference, within a dwelling. That's where I am getting mixed up, we were discussing commercial useage.

 

[fall-apart-dave]

Not overkill at all

How so? 2.5 to ring, why would there be a benefit to an increased csa to the rcd? (Genuine question, not trying to pick a fight).

 

[davesparks]

How so? 2.5 to ring, why would there be a benefit to an increased csa to the rcd? (Genuine question, not trying to pick a fight).

The ring is constructed of 2.5mm conductors having a rough equivalent overall CSA of 5mm, therefore as a rough equivalent the cable required to feed it must be equal to 5mm ( 2x2.5mm ) and the next standard size is 6mm. (I say rough equivalent as that is the dumbed down for idiots version of how a ring works)

Plus the smallest size of tails available (that I have ever used and afaik) is 6mm although that is not very common

 

[fall-apart-dave]

The ring is constructed of 2.5mm conductors having a rough equivalent overall CSA of 5mm, therefore as a rough equivalent the cable required to feed it must be equal to 5mm ( 2x2.5mm ) and the next standard size is 6mm. (I say rough equivalent as that is the dumbed down for idiots version of how a ring works)

Plus the smallest size of tails available (that I have ever used and afaik) is 6mm although that is not very common

Sorry yes my bad, you are right. I'm still thinking about radials with the commercial set up that came up before not a ring final circuit. Parallell thinking, too wrapped up in my own thoughts about what was discussed in the classroom, rather than the ring talked about here. no need to dumb down on my account, but easier to use rough figures to illustrate a point I get that.

 

[davesparks]

Sorry yes my bad, you are right. I'm still thinking about radials with the commercial set up that came up before not a ring final circuit. Parallell thinking, too wrapped up in my own thoughts about what was discussed in the classroom, rather than the ring talked about here. no need to dumb down on my account, but easier to use rough figures to illustrate a point I get that.

Then stop thinking about the last job or making assumptions. If you had made the same mistake in the real world it could have resulted in a fire.

I would be seriously concerned about someone who thinks 2.5 is good for 43.5 amps calling themselves an electrician

 

[hightower]

Davesparks - would that be a lollipop circuit (single leg out to RCD, where it splits to a ring)? I've heard the term bantered about but haven't come across it.

 

[fall-apart-dave]

Then stop thinking about the last job or making assumptions. If you had made the same mistake in the real world it could have resulted in a fire.

I would be seriously concerned about someone who thinks 2.5 is good for 43.5 amps calling themselves an electrician

Yes Dad. Sorry Dad. Won't do it again Dad. As for "real world" it's a far cry from discussing something at daft o'clock when I'm not giving it my full attention now, isn't it..? Annnd I didn't, at any point, say "yeah sure 43.5 amps is fine on 2.5, crack on!", I simply got my wires crossed (wahey! See what I did there..?) and realjsed afterwards and even said sorry (lord knows why!) when you pointed it out. Still, I'm sure the op is finding all this very useful, but lets not stopp to dressing folk down and giving out spankings, that'll make us all look like petty kids in a playground trying to get one up on one another.

 

[GMES]

All this faffing about, just get a new Board put in, by the time you add the labour up and new Garage cu and new tails etc, you've paid for a new Dual Board.
And the ironic thing is usually they need extra sockets to plug their new 1K TV and sound system into but won't shell out to have the job done correctly.

 

[fall-apart-dave]

All this faffing about, just get a new Board put in, by the time you add the labour up and new Garage cu and new tails etc, you've paid for a new Dual Board.
And the ironic thing is usually they need extra sockets to plug their new 1K TV and sound system into but won't shell out to have the job done correctly.

Folk jump at spending cash though, especially when "it was just fine before" and you are "only putting some wires in" - it is funny how people will wince at a small price difference between doing things half arsed and making serious improvements. My next door neighbour is still moaning about a £80 bill for "20 minutes work" when the electrician he used "tried to rip [him] off" when he had the nerve to recommend his lighting be split into two circuits while he was in there (his house has 3 cbs, upstairs sockets, downstairs sockets and all lights).