Sub Board fed from a plug top, EICR Coding

[7029 dave]

Everyone is being fooled by the appearance of the plug and socket, due to familiarity with the socket outlet as a means of connection for portable appliances. The plug here is not part of a portable appliance, so the dedicated plug-and-socket arrangement becomes a piece of switchear along the run of submain from main DB to conservatory DB. Consider it to be equivalent to an FCU, but using withdrawal of the plug to achieve double-pole isolation. No-one would argue that a permanent circuit fed from an FCU is not part of the electrical installation, surely?

Then, the question is whether as a piece of switchgear, the plug-and-socket is adequate for the purpose. Is its current rating high-enough for the design load, for example,? What about the COP guidance that limits the BS1363 plug earth pin to a maximum design leakage of 3.5mA? You would not really want that limitation on a submain. Used as an isolator, it also switches the CPC, which it is not supposed to do. Overall, I see this as an inappropriate piece of switchgear on the submain and would code it according to its shortcomings in that role.

For anyone still convinced that connection via a plug excludes the conservatory from the installation, consider a theatre-lighting system where all the circuits are patchable. Every dimmer channel (=DB way, which might number dozens or hundreds) terminates in one or two socket-outlets, often directly adjacent to the DB. Every installed circuit cable leading off around the building begins with a plug that can be placed in any of these outlets, like a telephone exchange. Would you then consider that none of the installed wiring is part of the installation?

Note that in the theatre patch panel, the CPC of all the circuits connects to the MET so that it does not rely on the contact of the plug and socket, and remains connected with the plug out. The plug and socket CPCs are also connected for completeness.

I agree, just because its on a plug top, it's no difference as a 13A FCU, and the intention is a permanent supply feeding the CU.

 

[Lucien Nunes]

you should not be posting such long dissertations after beer o'clock.

Beer o'clock is tomorrow round these parts.

If it were plugged into a generator it would after all.

Another good example. A entire site powered by a sled-mounted generator might start with a plug on the end of a cable poking out of the side of the building. And what about a backup generator with a transfer switch fed from the mains and a sled-mounted genny? Permanent installation when it's on mains, but magically becomes temporary when the mains fails and it transfers to the genny?

Wiring and accessories fixed to the building fabric, intended to be used as the principal electrical installation in that part of the building, are part of the fixed installation. Obviously if someone puts up some disco lights fed from a plug, independent of the normal lighting required to meet building regs, that is arguably a temporary addition.

 

[James]

Point is it isn't permanently connected.

By that logic, if I fitted a plug and socket between the meter and consumer unit at a property that was rented out, the EICR would only have to cover the socket and not the house that is plugged into it??

 

[7029 dave]

The big question is if the CU in the conservatory falls under part requirements plus all final circuits connected to it, then it has to be deemed part of the installation.

 

[pc1966]

I suspect it was done this way to avoid Pert P notification.

I also suspect the reason it is not mentioned in the regs is nobody in their right mind would do this (put a CU and related fixed wiring system on a 13A plug all the time), until Part P made it notifiable and costly for a non-scam person otherwise.

 

[7029 dave]

I suspect it was done this way to avoid Pert P notification.

I also suspect the reason it is not mentioned in the regs is nobody in their right mind would do this (put a CU and related fixed wiring system on a 13A plug all the time), until Part P made it notifiable and costly for a non-scam person otherwise.

Desperate measures in this case.
Appalling design method.

 

[Lister1987]

Of course you can mention it but you will have difficulty putting a Regulation against it as it is outside the scope of BS7671.

110.1.1.i lists the domestic premises as being in scope.

110.1.2i lists circuits upto 1000 VAC as being in scope

110.2.vi alterations or additions to existing installations and cases where an addition of alteration would affect the existing installation, which would put it in scope.


134.1.1 Good workmanship & Considerations to manufacturers' installation ?

I can't see the manufacturer agreeing being supplied by plugtop as an acceptable installation method. We can argue HOW it is installed excludes it from 7671

There may be more but on a purely fundamental level you can argue it's inclusion in an EICR

 

[Ryan G]

Thanks again for all the responses. I’m back and forth with how to code it.

At the moment I’ve got it down as a C3 - reasoning being the 1.5mm cable is capable of taking 16A which is what the MCB is rated at, and there’s no signs of thermal damage.

Its a bad design tho, but that doesn’t really fall under my remit as long as it’s safe. Any current flow at greater than 16A would trip the MCB and it’s RCD protected too.

Am I wrong to keep it as a C3?

 

[Deleted account]

Thanks again for all the responses. I’m back and forth with how to code it.

At the moment I’ve got it down as a C3 - reasoning being the 1.5mm cable is capable of taking 16A which is what the MCB is rated at, and there’s no signs of thermal damage.

Its a bad design tho, but that doesn’t really fall under my remit as long as it’s safe. Any current flow at greater than 16A would trip the MCB and it’s RCD protected too.

Am I wrong to keep it as a C3?

It’s your call . your the inspector. having Read and participated in this post I’d say there Is more than one right answer.


The fact you’ve identified an issue is proof that you’ve done your job. Code it or don’t code it however, but I’d put an extra explanation on this one.

I won’t say I agree with the C3, but I won’t disagree if you chose to go to with that.

 

[UKPN]

Thank you all for your inputs so far.

Is there anyone who disagrees with a C3?

The sub-board had 4 circuits:- 2 x Radial socket (each supplying one socket) 1 x Lighting (supplying 2 wall lights) and 1 x 20A air conditioning unit.

It is not a question with disagreeing. But are you one of an ever increasing group who feel they must code, and then a C3? Go on break the mould, dont code it.
Regards, UKPN

 

[Lister1987]

It is not a question with disagreeing. But are you one of an ever increasing group who feel they must code, and then a C3? Go on break the mould, dont code it.
Regards, UKPN

I say break that mould, code it and have conviction in your reasoning for the coding.

 

[Pete999]

Thank you all for your inputs so far.

Is there anyone who disagrees with a C3?

The sub-board had 4 circuits:- 2 x Radial socket (each supplying one socket) 1 x Lighting (supplying 2 wall lights) and 1 x 20A air conditioning unit.

LI for ludicrous Idea hope that's spelt right

 

[UKPN]

I say break that mould, code it and have conviction in your reasoning for the coding.

I think "proof" is the more appropriate word.
Regards, UKPN

 

[Lister1987]

I think "proof" is the more appropriate word.
Regards, UKPN

The proof is outlined above (in the eyes of this person), not everyone will see it the same, that said we're talking a C3 and won't fail an EICR, so why are we discussing it ?
.
I look at it from EAWR Defence point should it go bad.

Judge; As the competent person what did you do to make the person ordering the works aware of the issue?

I'm not sure a footnote and the reasoning for not including it in the scope being 'its on a plugtop guv' would be much defense, a coded item on the other hand and a justification for inclusion in scope stating that issue and perceived non-compliance, would hold more weight.

 

[Ryan G]

It is not a question with disagreeing. But are you one of an ever increasing group who feel they must code, and then a C3? Go on break the mould, dont code it.
Regards, UKPN

I’m not sure if I’m part of an ever increasing group or not, but if I see something that isn’t up to scratch then I feel it’s worthy of coding. Especially as the wiring of the extension seems fairly recent.

A C3 won’t fail the installation .. just means it could be better.

If you wouldn’t code it, how would you justify that you haven’t?