Heaters - spur or separate circuit?

[Hallsy]

I am wiring a shed as follows:

40A MCB at house CU on non-RCD side feeding 3 core 6mm SWA up to shed (30m). This has been installed by NICEIC spark.

I am going to do the wiring in the shed, which will then be tested & signed off by above spark.

I had planned to use a 32A 30mA RCBO in shed CU, with a 20A radial (2.5mm) feeding 5 double sockets, 16A radial feeding 2 x 1.5kW heaters, and 6A lighting circuit.

I am now in two minds whether it would be better to just use a ring on the sockets, back it up by a 32A MCB, and use two switch spurs from the ring to feed the 1.5kW heaters, fused at 10A each.

I am of the opinion that the heaters on a separate circuit would give more headroom for the ring main (or allow a radial to be used), but is it necessary if a 32A ring is only supplying 5 double sockets? The highest loads will likely be the heaters, no compressors or anything like that going to be used.

Any advice welcome

 

[ban-all-sheds]

The advice is to ask your electrician.

a) you are paying him for his services

b) as he is the one putting his livelihood on the line by falsifying official documents (stupid pillock) the least you could do to mitigate your part in this shameful conspiracy is to make sure he's happy with it all.

 

[chapeau]

b) is somewhat harsh.

The OP put the SWA in 'by the book'. He displays an understanding of electrics and is asking for advice. It's a shed so I assume all cable will be reasonably easy to inspect after it has been put in. The OP could easily just do it himself and in reality nobody would ever be the wiser. He is having an electrician look it over who I assume will ensure it is safe. He is providing custom for an electrician in these difficult times. 'Shameful conspiracy' is a funny way to describe this.

 

[rebuke]

b) is perfectly accurate - if the spark is signing off the work (presumably under Part P) then he is declaring to the LABC that he has done all the work himself, when in fact he hasn't. While I have no problem with sparks getting the householder to do some of the grunt work (digging trenches, chasing walls etc) - these should be to the sparks design (i.e. he/she marks out where the chase should be etc) - simply testing and signing off something you haven't designed is not on...

 

[Hallsy]

Hold on a minute here.

As has been suggested I am indeed a qualified electrician, albeit an electrical engineer, working in an industrial environment.

As I am not part of any competent persons schemes the work will be tested & checked over by someone who is. How is this any different to me applying to LABC, doing the work, then one of their guys coming out & signing it off?

I know of a few electricians who work for a contracting firm that do both industrial & domestic, not all of them can sign off their work under Part P, but they will all be involved with the work. Are you saying this is illegal?

At the end of the day I was running my thoughts by some of you guys who do domestic day in day out, if one of you guys popped up asking a techy or industrial type question, I'd do my best to offer advice without judging anyone.

 

[rebuke]

The difference is the LABC are legally authorised to cerify other peoples work, members of a competent persons scheme are only allowed to certify their (or their firms) own work - the firms who do both industrial & domestic will have a member of a competent person scheme signing off on it, at which point that person is signing to say they were in charge of the design, installation and testing, i.e. other sparks who worked for their firm on the project were simply doing things as specified by the person signing off - whether they were or not is a different question - if they weren't (e.g.. person signing it off hadn't seen the job until it was done) then he/she is breaking the law by signing the certificate (I'm not naive enough not to believe this probably happens on quite a large scale though)...

Essentially, if you said what you wanted to the spark, then install it as per his design (i.e. he tells you what breakers, cable routes, etc to use), then I see that as no different to the firm way - while strictly speaking I think the scheme providers say you should be an employee, I can understand people ignoring that. What you've said however is you are going to install it and then he's going to come out and inspect it - i.e. it's not to his design...

 

[ColJack]

how is signing off "the firms" work any different?
he hasn't done the work himself..
or if he works with a 'prentice, then he hasn't done all the work himself..

the guy is just being his unpaid 'prentice for this job..

 

[rebuke]

As I said, if he was just acting as someone working for the spark (i.e. installing to the sparks design etc), then I personally see no problem with it (although I suspect it's against the scheme providers rules). The problem is that isn't what has been described here - the OP is clear that it is not the spark designing the install within the shed, since it's asking questions about how to do it...

 

[ColJack]

if he fills in a 3 sig test sheet and gets the guy to sign for the design, and installation, as long as the test is filled in by the sparky? only the same as if he's sent to test someone elses work for "the firm"..

 

[rebuke]

I'm not talking about the EIC though, I'm talking about Part P - while I agree a spark could quite legitimately do the testing part of a 3 part EIC, and let the DIYer do the design and installation parts, under a Part P competent persons scheme you are signing to say that you have done or directly supervised *all* the work yourself (i.e. design, install and test) - so just doing the testing isn't enough - you need to have been the one to specify where the cables should run, what breakers etc etc...

 

[ColJack]

which means that a "firm" can't be part P registered, each individual sparky would have to be... they can't sign for work done that they didn't do themselves..?

if they can, then how is that any different to saying that for the duration of that job, the person that did the install was working for you as an unpaid trainee?

 

[rebuke]

As far as I am aware firms can't be specifically (i.e. it has to be a nominated person that registers).

My interpretation (which might be wrong, I'm not a spark, and haven't investigated the various scheme providers rules etc), is that the person signing it off has to have been in charge of the whole process (design, install and test), so perhaps when I say work done themselves that's wrong...

 

[ColJack]

but by definition you can't be incharge of the install if someone else is doing it, even if it's on behalf of your company..

you don't know for a fact that the installing electrician has put the cables in the right places if they've been plastered over etc...

the guy signing would have too travel to every site and inspect first fix and second fix like the LABC does..

 

[rebuke]

True, but that's probably the intention - the person signing off that it complies with Part P *should* be inspecting it at the various stages!

I know in reality that is unlikely to happen, but I guess as a spark you at least have the fact that the people doing the work are being paid by you / your firm, are probably qualified sparks in their own right etc - so you've at least got a contractual comeback against them if they have done something wrong, whereas with a DIYer, you are literally relying solely on their word - and they're effectively therefore paying you to falsify a document...

 

[ColJack]

some of the DI work that I've seen out there is of a far worse quality than that of some of the DIY installers.. for example the OP.. he's a sparky, just not a domestic one, so him I'd be ok with to do the work.
myself, I'm not a domestic sparky, but I can easily do it, it's just that as a rule I do industrial and commercial installs..

as a result, my uncle ( who does domestic ) is more than happy to sign off on my kitchen install when I get round to doing it..