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What does BS7671 mean by an "installation coupler" 411.3.3 Note 5?

JHFE

What does BS7671 mean by an "installation coupler"  411.3.3 Note 5?

Is this a proprietary connector or standard connector used in a singular and specific way purely for a particular installation application?

I will be providing a new circuit in a domestic setting which supplies power to a yet-to-be-installed garden office pod.

 

The Pod supplier/builder has specified a 32amp 230v BS EN 60309-2 Commando socket at the end of the circuit.  They then deliver and build their pod and connect a flexible lead from the back of the pod to the socket/circuit I provide.  This in turn powers a 40A 30ma 2-way consumer unit, pre-wired at the pod building factory. In other words, outlets and lighting in the pod are RCD protected.

 

My circuit will come from CU (DB2) which I will fit and SWA will run from DB2 all the way to the outlet near the garden pod. (15-18 metres on 6mm2 SWA)

 

My question relates to RCD requirements.

 

In the interests of Selectivity, I could run the SWA from just an MCB, as the SWA negates RCD protection for the cable itself.  However, if the 32amp commando I fit is classed as a "socket outlet", I could be failing to provide RCD protection where BS7671 requires it.

 

411.3.3 Note 5 pg65 A2:2022 - states that an "installation coupler" "is not regarded as a socket outlet for the purposes of this regulation"

 

Would it be fair to class this connection between pod and circuit as an installation coupler?  It is unlikely to be accessed by lay persons to, let's say, power a lawn mower and will be behind the pod and not readily accessible to lay persons, once the pod is installed.  It will more than likely be connected once and stay permanently connected for many many years without interference.

 

Or

 

The 32amp outlet used to connect the pod to power is without question a socket outlet and therefore 411.3.3 must be obeyed and the cable run from DB2 to the outlet must be RCD protected?  Even if I sacrifice selectivity as the lesser of 2 evils and have 30ma upstream and downstream?  (or fit time delay upstream)

 

Any advice is much appreciated. Thumbsup tone1

 

Cheers

James

 

Other info.  single phase, domestic setting, TNCS, 8-year-old property, "17th edition" dual RCD (AC wave) split board for the main house, no existing SPD.

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  • 0

    I think that many of you are forgetting that these pods are not fixed permanent buildings, they may well be moved around regularly as the grass or whatever becomes worn. A plug and socket arrangement seems very sensible to me. They should be considered to be similar to a caravan (where the same often applies). I quite understand the manufacturer fitting a plug, it is very sensible, and the only way that an electrical certificate can be provided. A further point is that fitting a plug and socket makes this unit NOT part of the fixed Electrical Installation and so BS7671 does not apply, so the Eland stuff is also irrelevant. Just because it looks like a fixed installation does not make it one!

  • 0 in reply to David Stone

    Don’t be silly, these are not movable “caravans” they are permanent structures. The manufacturer states that normally allow two days for erection.

  • 0 in reply to David Stone
    David Stone said:
    NOT part of the fixed Electrical Installation and so BS7671 does not apply, so the Eland stuff is also irrelevant. Just because it looks like a fixed installation does not make it one!

    The scope of BS 7671 covers installations that are not fixed, including temporary installations, but specifically mobile / transportable units (Section 717 is really a very wide scope and potentially what's being described with moving the structure around, if this is indeed one of those).

  • 0 in reply to gkenyon

    One could potentially include it in 717 that Graham it is true, but then the definition between appliance and fixed is blurred even further. However if you try to make it a "caravan" the connecting cable etc. is defined and that is not what is supplied with these pods! Clearly then they are not intended by the manufacturer to be covered by 717, and he sees that the best definition is as an appliance connected with a plug and socket. As they are wooden, a lot of 717 is irrelevant, and a normal 30mA RCD supply would seem to me to be entirely safe. Feature creep is a terrible thing!

  • 0 in reply to David Stone

    Agree. If the makers decide that bits of the UK national wiring regs do not apply, but their own rules do, then that is a matter for them and their legal team. Showing that it is equivalently safe to either should do.

    If an installer follows the maker's advice and plugs the building in, he has some defence, in that  the maker's inductions said it was what should be done.

    Not to do so is equally well defended by ' the voice of BS7671 told me to do it' .

    Which is the best course is a judgement call when you rock up on site and look at it - is being able to unplug it going to be useful or not - when they go on holiday perhaps ? 
    I might do either and I might put the socket in some sort of box or cupboard , given it is un-shuttered and un-interlocked and it sounds like more of  a domestic situation than the usual portakabin at a pop festival.

    Mike.

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  • 0 in reply to David Stone

    Agree. If the makers decide that bits of the UK national wiring regs do not apply, but their own rules do, then that is a matter for them and their legal team. Showing that it is equivalently safe to either should do.

    If an installer follows the maker's advice and plugs the building in, he has some defence, in that  the maker's inductions said it was what should be done.

    Not to do so is equally well defended by ' the voice of BS7671 told me to do it' .

    Which is the best course is a judgement call when you rock up on site and look at it - is being able to unplug it going to be useful or not - when they go on holiday perhaps ? 
    I might do either and I might put the socket in some sort of box or cupboard , given it is un-shuttered and un-interlocked and it sounds like more of  a domestic situation than the usual portakabin at a pop festival.

    Mike.

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