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Need for Additional protection for circuits serving zones 1 and 2 in a bathroom

Former Community Member
Former Community Member
I am looking at a like for like replacement of a shower and trying to avoid the cost of replacing the CU if possible as the property is likely to be completely gutted in the next 12 months and fitting a new CU before this is difficult to justify.

I am confused because the regs seem to contradict themselves.


701.411.3.3 states Additional protection shall be provided for all low voltage circuits of the locations including circuits that pass through zones 1 and or 2.... by the use of one or more RCD's.


Then 701.415.2 States that supplementary bonding is required unless main bonding is in place and all circuits are protected by a 30mA RCD.


To me 701.411.3.3 seems to state an RCD is always required but 701.415.2 implies that if supplementary bonding is in place then an RCD is not essential.


I would be interested in your views.


Thanks


Alan
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    Then 701.415.2 States that supplementary bonding is required unless main bonding is in place and all circuits are protected by a 30mA RCD.


    To me 701.411.3.3 seems to state an RCD is always required but 701.415.2 implies that if supplementary bonding is in place then an RCD is not essential.


    I would be interested in your views.


    Thanks


    Alan


    If all of the requirements of 701.415.2 (iv) (v) and (vi) are met than no supplementary bonding is required. An R.C.D. is required though.


    The installation of an R.C.D. is a wise precaution with a shower circuit. I would recommend one.


    Z.


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    https://www.youtube.com/watch?v=AlU69Y6NcxQ



    Z.
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    Invigorating live shower water......

    https://www2.theiet.org/forums/forum/messageview.cfm?catid=205&threadid=32202


    Z.
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    Note ALL of the requirements will allow you to omit supp bonding. All not just any. Therefore main bonding must be in place if required and it must be continous from any metal pipework to any metal pipework in the bathroom, plus all ccts of the bathroom must be 30mA (or less) RCD protected and that includes all ccts running thru the bathroom as well.
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    701.411.3.3 makes additional protection by RCD mandatory. There are no conditions under which it may be omitted.

    701.515.2 requires supplementary bonding under certain circumstances.


    So you must have RCD protection and supplementary bonding unless all the circuits of the location are protected by ADS i.a.w. 411.3.2 - that's your MCB in a TN installation; and main protective bonding is in place.


    If the existing CU does not provide RCD protection, you could put one in a separate enclosure adjacent to the CU. Not ideal, but good enough for a temporary solution and it will make the circuit compliant.
  • Former Community Member
    0 Former Community Member
    ebee:

    Note ALL of the requirements will allow you to omit supp bonding. All not just any. Therefore main bonding must be in place if required and it must be continous from any metal pipework to any metal pipework in the bathroom, plus all ccts of the bathroom must be 30mA (or less) RCD protected and that includes all ccts running thru the bathroom as well.


    Just to clarify that I do understand that all of the requirements need to be complied with, I was just trying to reduce the length of my post by omitting some text.

    I think I am leaning towards biting the bullet and replacing the consumer unit, although I am going to take a look at the rest of the house before committing to anything. I have horrible feeling I am going to find multiple other issues and the project will snowball.


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    I am confused because the regs seem to contradict themselves.

    Not really, as the new regs only apply to new work. It's entirely possible to say add a new circuit to a bathroom, have the new work fully comply with the latest regs, but still be in the situation of not being able to meet all the conditions for omitting supplementary bonding. E.g. if you add a new 30mA RCD protected shower circuit, but the existing lighting circuit is not RCD protected - you'd still need supplementary bonding (or change the lighting circuit to have 30mA RCD protection of course).


    It's not all just about RCD protection for the bathroom circuits either - if pipework for example could import a fault from outside the bathroom (especially from a say 5s disconnection time circuit) then it's likely that supplementary bonding would still be needed even though all the bathroom circuits had 30mA RCD protection.


    On the other hand, it's usually possible to add 30mA RCD protection without a full CU change - e.g. adding a separate enclosure next to the CU for a RCCB for the shower circuit is perfectly acceptable electrically.


    Arguably if it's an existing circuit and you're simply replacing the appliance like-for-like, there's no requirement to bring the existing circuit up-to-date. Most would probably recommend taking the opportunity to do so - and the manufacturer's instructions for the new unit would most likely ask for 30mA RCD protection - but there might be a modicum of wiggle room there.


        - Andy.
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    AJJewsbury:

    Arguably if it's an existing circuit and you're simply replacing the appliance like-for-like, there's no requirement to bring the existing circuit up-to-date. Most would probably recommend taking the opportunity to do so - and the manufacturer's instructions for the new unit would most likely ask for 30mA RCD protection - but there might be a modicum of wiggle room there.


    Is this DIY or paid work?


    If DIY, there is no obligation to comply with BS 7671, nor is a like-for-like replacement notifiable.


    If paid work, the circuit really ought to be compliant and, of course, a MEIWC will be issued.


    Nothing has been said whether the premises are owner-occupied, vacant, or let.


  • Former Community Member
    0 Former Community Member
    Chris


    I am doing this with a friend who is the owner occupier of the property. I am also training as an electrician, expect to be qualified May/June. I am working towards finding a local electrician who will take me on so that I can gain some experience and may get them involved in this.


    After reading he feedback and thinking about it I have decided I am not comfortable being involved unless the bathroom circuits are protected by RCD and of course all the other requirements like earth bonding are put in place. I also realise that as it's more than a like for like replacement I am not currently qualified to do it and will need to get someone else involved or wait.
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    Building  regs do not require you to bring it to the latest specification,  just not to make the existing situation worse, so a simple replacement onto the existing wiring for private use would be perfectly legal, and no more dangerous than the original.

    It would not of course comply to current regs, but then more than half the houses in the UK probably are in that category.

    If you are concerned then an RCD in a box is the sort of thing that could go in a box  beside the bathroomif you did not want a major rewire.

    Mike.

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