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Location of Pull cord for shower isolator outside zones but could still be touched.

Former Community Member
Former Community Member
Hi 


Sorry if this is a bit of a basic question, I am still in training as an electrician and trying to make sure I understand how rules are applied in practice.


I have been thinking about where shower isolator pull cord switches can be installed following section 701 in BS7671 and having looked at a few other books I am a bit confused as my interpretation of the rules doesn't match what I would consider as common sense.


From my understanding a pull cord switch can be mounted above zone 1 with the insulated cord dropping in to zone 1 and as the switch is outside the zones it doesn't need anything beyond standard IP2x protection based on 701.512.3.

Zone 1 extends to 225 above the fixed floor height or where the shower head is fixed at a height greater than 225 then zone 1 extends to the height of the shower head. There doesn't appear to be any mention of extending the zones if the shower head is not fixed and in theory could be directed at the ceiling.


The bit that doesn't make sense to me is that there are lots of precautions to keep water and electricity separated and to prevent people coming in to contact with electricity when wet. If my interpretation is correct a pull cord switch can be mounted above the shower basin at 225cm, which I as an average height person can touch quite easily, especially as the height appears to defined from the floor and not the shower basin (fig 701.2(C)). Also if the shower head is not fixed it can be pointed directly at the switch. There doesn't appear to be any requirement to protect the switch against water ingress.


I know it's unlikely but I could spray the switch with water and then put my hand on it whilst holding a shower head that could presumably be connected to earth by the flexible pipe.


I know everything in a modern installation should be protected by bonding and RCD's but to me this feels fairly risky.


Is there something I am missing?


Thanks


Alan 

Parents
  • 0
    You could do this  - but the part of pull switch you need to touch to operate it is the cord, not the enclosure.  There should be an insulating bead in the string between the switch and the bit you grip - a soggy knot may not quite do.

    You may prefer to read it that the cord part of the switch can be in any zone, but the mechanism should be out of zones and  suitably IP rated - that last part is not a bathroom specific requirement, other more general rules indicate that all fittings, even ones on the ceiling, should be suitable for their environment. It goes without saying that all non waterproof  fittings in a bathroom need to be sited where they will not get wet with normal use (or credible abuse ! ) of the shower. In reality then , the switch body would be placed out of  splash reach.


    As a side note arguably you do not need an isolator at all, and for repairs to switch at the MCB would do, or a rocker switch outside the bathroom, which is the preferred approach in other parts of the world, actually the use of pull switches at all seems to be a very UK thing, and pre- dates the bathroom zones as we know the, which came in around 2002 or so.


    Mike.
Reply
  • 0
    You could do this  - but the part of pull switch you need to touch to operate it is the cord, not the enclosure.  There should be an insulating bead in the string between the switch and the bit you grip - a soggy knot may not quite do.

    You may prefer to read it that the cord part of the switch can be in any zone, but the mechanism should be out of zones and  suitably IP rated - that last part is not a bathroom specific requirement, other more general rules indicate that all fittings, even ones on the ceiling, should be suitable for their environment. It goes without saying that all non waterproof  fittings in a bathroom need to be sited where they will not get wet with normal use (or credible abuse ! ) of the shower. In reality then , the switch body would be placed out of  splash reach.


    As a side note arguably you do not need an isolator at all, and for repairs to switch at the MCB would do, or a rocker switch outside the bathroom, which is the preferred approach in other parts of the world, actually the use of pull switches at all seems to be a very UK thing, and pre- dates the bathroom zones as we know the, which came in around 2002 or so.


    Mike.
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