Extending Cooker Feed - Notifiable?

[JohnW2]

So no - whatever their reasons were I am in no doubt about their intentions.

I've been thinking of this a bit more in relation to how it applies to Daniel, and there seems to be one small technical complication.

The 'first stage' of his work, at least per his 'Plan A', consists of extending the unused cooker circuit into his garage. As we've discussed, if both ends of the SWA are terminated within buildings, it's not part of an outdoor installation, and therefore not notifiable on that account. However, the extending would only be non-notifiable if it were for the purpose of adding sockets and/or fused spurs and/or lighting. To remain within the law (without notifying) he would therefore initially have to connect the circuit to a socket, fused spur or light - simply extending the circuit, with nothing connected to the end of the SWA would seem to not theoretically meet the requirements for non-notifiability. Given the latest revelation (at least, as far as I am concerned!) about exemption of small outbuildings from most Building Regs (seemingly including notification of electrical work), if he 'subsequently comes across' that electricity supply in his garage, I presume he could 'add' anything he wanted to it (e.g. a CU, if he decided to go that route) without notification - although he obviously would still have to comply with part P.

I've also realised that Class 6 of Schedule 2 also includes many/most sheds, since it includes all detached buildings ≤15m², even if they are built of combustible materials (provided only that they don't contain 'sleeping accommodation') ... so it seems that electrical work in most smallish sheds is also exempt from any notification requirements!

Kind Regards, John

 

[scousespark]

The current set up has a radial, which can be extended, without rewiring. The ONLY reason the garage CU is being discounted is cost.

Hmmm. If I understand what you're saying, extending the (4mm²) cable without rewiring (and having a garage CU) would limit the house-end MCB to 32A, which, as I've discussed, will seriously frustrate attempts to get discrimination from an MCB in a garage CU - which appears to be one of the major issues you've been raising. On the other hand, if you mean that the only reason a garage CU is being discounted is because of the cost (including notification) of running a higher CSA cable all the way back to the CU, so as to improve prospects of discrimination, then I would partially agree.

Only 'partially agree', because another reason (for not having a garage CU) would be if it wasn't considered necessary. As I asked before, do you believe that there is any problem with not having a garage CU, other than that a fault on the garage sockets circuit would take out the garage lights?

Even in the dumbed down world of electrical training, design takes safety and convenience into account. The additional cost of notification is not a design consideration.

Agreed. Do you see any safety problems with the design without a garage CU - and, as above, is the only convenience issue you can think of the fact that a garage sockets fault would take out the garage lighting?

Kind Regards, John

I was only referring to the cost of notification. Your option would work, but it's a poor choice.

 

[JohnW2]

I was only referring to the cost of notification. Your option would work, but it's a poor choice.

Fair enough - but, as I keep saying, it's not 'my option' - rather, the option I have seen repeatedly suggested/advised/advocated in this forum. As for your opinion that it is a 'poor choice', you seem to have forgotten to respond to this bit of my last post:

Even in the dumbed down world of electrical training, design takes safety and convenience into account. The additional cost of notification is not a design consideration.

Agreed. Do you see any safety problems with the design without a garage CU - and, as above, is the only convenience issue you can think of the fact that a garage sockets fault would take out the garage lighting

Kind Regards, John

 

[dhutch]

Ok, if it comes to it, I can run a digi vernier over the individual strands and do a sum on csa!

Indeed so. 4mm², 6mm² & 10mm² should all have 7-stranded L & N conductors. The diameter of individual strands should be 0.85mm, 1.04mm and 1.35mm respectively.

Kind Regards, John

Seven strands, each measuring around 1.04/1.05 , so it appears to be 6mm^2 as expected, checked at both ends, no outer markings visible.


Daniel

 

[scousespark]

I was only referring to the cost of notification. Your option would work, but it's a poor choice.

Fair enough - but, as I keep saying, it's not 'my option' - rather, the option I have seen repeatedly suggested/advised/advocated in this forum. As for your opinion that it is a 'poor choice', you seem to have forgotten to respond to this bit of my last post:

Even in the dumbed down world of electrical training, design takes safety and convenience into account. The additional cost of notification is not a design consideration.

Agreed. Do you see any safety problems with the design without a garage CU - and, as above, is the only convenience issue you can think of the fact that a garage sockets fault would take out the garage lighting

Kind Regards, John

Extending the existing circuit, does not present a safety issue. The issue is that the 'design'is being driven by the requirement to not need to notify.

When I posted earlier, I was referring to the decision not to change the breaker and cable. This makes the installation of a garage CU, as the existing 32A supply makes that pointless.

You are right that the cost of notification is fairly irrelevant to an electrician, whereas it is a major cost for anybody not registred in a scheme. However, you regularly criticise the quality of electrical work you come across. In this case your criticsm is being levelled because you don't see the need for proper design as it leading to an extra cost.

 

[JohnW2]

Do you see any safety problems with the design without a garage CU - and, as above, is the only convenience issue you can think of the fact that a garage sockets fault would take out the garage lighting

Extending the existing circuit, does not present a safety issue. The issue is that the 'design'is being driven by the requirement to not need to notify.

It surely doesn't matter what is 'driving' the design - as I said, the question is whether the design is satisfactory in terms of safety and 'convenience'. It sounds as if, in terms of those things, you are probably now agreeing that it's OK.

You are right that the cost of notification is fairly irrelevant to an electrician, whereas it is a major cost for anybody not registred in a scheme. However, you regularly criticise the quality of electrical work you come across.

I think you're probably only remembering a very small proportion of my posts which irked you a bit - I wouldn't say that I 'regularly criticise electrical work'. Sure, what I say about electrical work | see will generally be negative, since there's no point in my repeatedly writing about the good work I've seen (which is obviously the great majority of it) - just as you don't expect to hear on the 6 o'clock news about all the planes and trains which haven't crashed, all the people who haven't been murdered or raped etc.!

In this case your criticsm is being levelled because you don't see the need for proper design as it leading to an extra cost.

I'm not sure I've really been 'criticising'. I do see the need for 'proper design', in the sense of safety, utility & convenience etc. However, I don't think that one should (as you at times seen to have been doing) criticise a design which is satisfactory in all those respects just because you feel it is being 'driven' by a desire to avoid the need for notification. If a design is satisfactory/'proper', then it is satisfactory/'proper', regardless of how and why it came into being, isn't it?

Kind Regards, John

 

[scousespark]

The fact that no effort is being made to limit the effect of a fault in the outbuilding makes this less satisfactory than it could be.

How can you say that the fact that the requirement to save money is driving the design is not relevant. On a C&G course, you don't get asked to design a circuit so it is as cheap as possible.

I don't get irked by your posts, as this is a discussion forum and you have every right to voice your opinions of work you've seen. I'm just giving my opinion. You the OP and everybody in the forum can take it or leave it.

In this case, the OP is so close to fully complying with the standards an electrician would adhere to.

 

[JohnW2]

The fact that no effort is being made to limit the effect of a fault in the outbuilding makes this less satisfactory than it could be.

Is that a reference to the one point I've conceded (that, without a garage CU, a garage sockets fault would take out the garage lights - whereas if one managed to get discrimination from a high-rated house OPD {hence meaty cable}, that wouldn't be the case with a garage CU) - or something else? If yes, is that the only 'design imperfection' you see with such a design?

How can you say that the fact that the requirement to save money is driving the design is not relevant. On a C&G course, you don't get asked to design a circuit so it is as cheap as possible.

For a start, cost often is a crucial component of 'the design process' (in any discipline or walk of life). However, that is not my point. I'm saying that you should judge the design purely by what it ends up as, regardless of how the designer 'got there'. Even if (s)he was lucky enough to arrive at a design which you regarded as 'optimal' by flipping coins or tossing dice, that would not make the design any less optimal, would it?

In this case, the OP is so close to fully complying with the standards an electrician would adhere to.

Indeed so. In fact, as we've discussed, it appears that the design without a garage CU is exactly what many electricians would do.

Kind Regards, John

 

[ban-all-sheds]

How can you say that the fact that the requirement to save money is driving the design is not relevant. On a C&G course, you don't get asked to design a circuit so it is as cheap as possible.

There's a difference between "as cheap as possible" and "cost is a design constraint".

 

[dhutch]

There's a difference between "as cheap as possible" and "cost is a design constraint".

Well this is it.

I dont want to do anything unsafe, and as an engineer and someone who did a few years working in 'lighting and rigging' while at university its pleasing to do it right. However in the cold light of day, for a house that im not planning to live in for life, if the whole job ended up being priced at a grand I will sack it off, and carry on running the garage off an extension lead, putting the money towards a dropped curb for my drive, or a new kitchen ceiling, or replacing the broken down double glazing units.


Daniel

 

[JohnW2]

How can you say that the fact that the requirement to save money is driving the design is not relevant. On a C&G course, you don't get asked to design a circuit so it is as cheap as possible.

There's a difference between "as cheap as possible" and "cost is a design constraint".

I'm not even sure that there is anything wrong with "as cheap as possible", provided there is an (implicit or explicit) qualification that one means "as cheap as possible whilst satisfying other design consdierations". As I said, cost is a crucial factor in the design process. Some of the most successful and innovative designs have been those which optimised cost and therefore brought products and technologies 'to the masses'.

Kind Regards, John

 

[scousespark]

My quote about the cheapest option didn't really convey what I meant here. The problem (forgetting about the current job) goes back to the fact that LABCS have never had the correct processes to deal with Part-P.
That's why the blanket cost is in place. I can empathise with the OP, as the notification cost is a constraint.

However, I don't know why JohnW2 is taking such issue with what I have posted.

Extending the circuit is an option, but it has drawbacks (limits the current to 32A (with 16 used for the welder) and a fault in the garage may affect the circuits in the house. Is this a correct assessment?

Also dhutch posted that he also wants a socket radial, lighting radial and possible emergency lighting. Do you not take this into account? If the C&G training ended at cable calcs, the courses would be very short.

My posts just point out that there is an option which negates these potential problems. The IET published a guide to supplying outbuildings in Autumn 2005, which recommended increasing the breaker rating and increasing the size of the cable feeding the garage (based on the estimated load). This option does make the job notifiable.

As a C&G qualified electrician, I would recommend the IET design. dhutch has options in front of him and can make his own decision.

Is any of this contentious?

 

[JohnW2]

However, I don't know why JohnW2 is taking such issue with what I have posted.

My only real issue was that, on a number of occasions, you said fairly scathing (certainly 'negative') things about a design which I personally thought was 'perfectly reasonable' and, more to the point, is a design which many of the electricians here and elsewhere recommend, and therefore presumable a design they install themselves. Yes, there is an arguably 'more perfect' approach, but that's not really the point.

As I said a number of times, whether or not any notification/cost consdierations were part of the reason why the design was being consdiered is really irrelevant - what matters is the design one ends up with, by whatever process. In fact, when these questions about garage supplies arise, there is very often no 'notification issue' - we are usually/often talking about a 'new circuit', making the job notifiable, regardless of the design - yet many still recommend the design which you do not seem very happy about.

Human nature and the subconscious being what they are, we are all influenced by all sorts of things. I wonder if you would have written quite the same in this thread if it had been an electrician, rather than mere me, who had been writing the things I wrote? I can well imagine that I might respond a bit differently (probably without even realising) depending upon whether I was responding to comments from a 'layman' or a professional colleague in relation to a field in which I am professionally qualified.

Kind Regards, John

 

[scousespark]

I'm sorry if you think I have been scathing and attacking you. It wasn't my intention and my responses have been slow, because I drop in and out of this site, as I don't have a lot of time on my hands.

I have been through this and the other outbulding thread and I don't think we are on the same page here. My responses have been specific to this particular job (not a generic view of feeding outbuildings). In this case, the post started with the wrong question. If dhutch only wants a 16A supply for his welder, the post is similar to the other post and extending the existing circuit is fine. However, he has said he want sockets and lights. That is the differenec between the posts. Using the existing circuit is an option. This is what I was refering to as the poor option, for the reasons already stated. to feed the welder, dhutch will need a 16A supply, so the sensible decision would be to do it now (although it would require notification).

 

[JohnW2]

I'm sorry if you think I have been scathing and attacking you.

No, I don't feel attacked at all, and yiu have been very civil throughout. Your involvement started on page 4, the message which stimulated/initiated most of our subsequent exchanges being:

I see, so I would just have the MCB in the consumer unit, which would protect the cable and everything beyond it, with then a 5amp FCU to the lighting. Interesting.

Exactly. That's the usual 'simple' supply to a garage.

You may have seen this, but it is not common for a detached garage. It's a poor design.

I still believe that what I said is essentially true - that what Daniel was describing was "the usual simple' supply to a garage". It's an arrangement I've often seen, one which is often suggested/recommended by electricians on this and other forums and is a design which many electricians seem to install. Everything which has followed has resulted from the fact that you called it a "poor design" - that's what I meant by 'scathing'.

I have been through this and the other outbulding thread and I don't think we are on the same page here. My responses have been specific to this particular job (not a generic view of feeding outbuildings). In this case, the post started with the wrong question. If dhutch only wants a 16A supply for his welder, the post is similar to the other post and extending the existing circuit is fine. However, he has said he want sockets and lights. That is the differenec between the posts.

I'm not quite sure which one you mean by 'the other post' (there are lots of garage/outbuilding ones about!), but I think we have interpreted the OP of this thread differently. Daniel said that he wanted to connect the unused cooker circuit to a 16A socket on the outside of kitchen wall, so that he could "run a cable from there for his garage/welder". I took that to mean a supply (power + lighting) for the garage (not just a supply for a welder), and he subsequently confirmed that he also wanted lighting ("5 fluoros"), and perhaps more than one socket.

This is what I was refering to as the poor option, for the reasons already stated. to feed the welder, dhutch will need a 16A supply, so the sensible decision would be to do it now (although it would require notification).

As I understand it, I think he probably doesn't need a 16A supply for his welder - at least not at present. As above, the 16A socket on the outside kitchen wall mentioned in the OP was, as I understand it (perhaps incorrectly!), simply a proposed (albeit unsatisfactory) means of 'attaching' the entire garage installation to to the unused cooker circuit. The OP said (on page 3) that his present welder works off a 13A socket - I suspect he thought that a fully-loaded 13A socket plus lighting added up to about 16A, and hence the need for a 16A socket on the kitchen wall. I therefore interpreted his requirement as being that of a "usual simple supply to a garage" (one or two 13A sockets plus lighting). Maybe I was wrong.

Kind Regards, John