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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 

  • 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.
  • 0


    If you decide to have an electric shower, where will it be fitted?
  • 0
    I don't think that BS 7671 is intended to protect people from deliberate acts of complete stupidity.


    When I take a shower at home, there is a fan just above my right ear i.e. in zone 1, where it is permitted. I could lift off the shower head and wash it out if I really wanted to! (How do you make a fan IPx-anything?)


    I had never given much thought to those beads which Mike mentioned - I had assumed that they are to facilitate replacement of the cord. Every day is a learning day in here!


    A pull-cord switch might well be not only above but also to the side of the zones; however, it doesn't take much to pull the end sideways into them.


    Incidentally, please do not fall into the trap of thinking that switches have to be outside a bathroom. Unless the bathroom is very small (and many modern ones are) there is plenty of room to install them by the door in the usual place.
  • 0
    " Incidentally, please do not fall into the trap of thinking that switches have to be outside a bathroom. Unless the bathroom is very small (and many modern ones are) there is plenty of room to install them by the door in the usual place. "


    PIRs fitted into the ceilings of small bathrooms and toilets work well. They don't like too much humidity so employ an extracter fan or take more cold showers.

    Legh
  • 0
    There doesn't appear to be any requirement to protect the switch against water ingress.

    You could indeed soak the switch if you were so minded. In the same way there's nothing stopping you unplugging a traditional kettle lead from the kettle and dropping the live end into a sink full of water, or leaving the cover off an outside light and leaving it switched on so the rain/snow gets in, or running an extension lead out into the garden and dropping the end into the pond.


    On the plus side, people tend not to do such things - partly because they have an inkling that it's probably a bad idea from a shock point of view, but also because it tends to cause more obvious damage - e.g. soaking the bathroom ceiling will likely ruin the paintwork and plasterboard of the ceiling and possibly the wall and floor coverings too (as the water spray directed upwards like that is unlikely to remain within the confines of the bath or shower).


    Also it's not so much that water and electricity is a bad mix from a shock point of view, as wet skin and electricity. If the body of a pull switch did get soaked most people would try and turn it off - at worst by pulling on the cord (as that's how they always switch it off) which would be unlikely to be hazardous as the wet skin is a long way from electricity still - very few I think would be tempted to handle the body of the pull switch in that situation.


    If you think it's poor now, just look back a few years where a plain unenclosed BC lampholder over the bath was the norm - the only precaution being a deep (Home Office) skirt around the lamp end of the holder to try and make it a bit more difficult to touch the contacts.


      - Andy.
  • Former Community Member
    0 Former Community Member
    Thanks for all the feedback, very informative.


    I thought about the option of just using the circuit breaker as an isolator but I believe the regulations state that a double pole switch is required to isolate for maintenance and the CB is only single pole. Have I missed something?

    Also I did take a look t see if IPX4 rated pull switches were available and didn't find anything.

    I am ok with the concept of the switch still being in a small bathroom, but just felt that putting it 1 or 2 inches from the edge of the shower wasn't particularly appropriate.


    I think in these situations my preferred approach would be rocker outside the bathroom or pull switch providing it's a reasonable distance from the shower.
  • 0
    The more general thing to realise is that the regs are a starting point, not the be-all and end-all. It is quite possible to design something foolish that meets the letter of the regs, and from time to time you will find things that are not regs compliant, but none the less, in that case, are the sensible thing to do.

    In reality some gumption on the part of the designer is assumed - and maybe from time to time it you will see an installation where that ability  has been left switched off.


    You are quite right, in practice  you would site the switch somewhere out of the firing line, and that may need to be be further away in a facility expected to be used by boisterous youngsters like a hostel or a school, than perhaps for some old folks home (but maybe not, depending on level of care needs and mental faculties expected )  Indeed the switch outside is problematic with kids who think it is great fun to turn off while their friend (soon to be enemy) is in it and another approach altogether may be better, as well as fixed shower heads....

    Mike.
  • 0
    I believe the regulations state that a double pole switch is required to isolate for maintenance and the CB is only single pole. Have I missed something?

    Only for TT systems - in (far more common) TN installations N doesn't need to be isolated (other than for the main switch in a single phase domestic and similar installation).


       - Andy.
  • 0
    I think in these situations my preferred approach would be rocker outside the bathroom or pull switch providing it's a reasonable distance from the shower.

    But as it then would (most likely) not be under the supervision of someone working on the shower, it would need to be capable of being locked-off.

       - Andy.
  • 0
    Alan B:

    I think in these situations my preferred approach would be rocker outside the bathroom or pull switch providing it's a reasonable distance from the shower.


    I am not quite sure why you need local isolation - doesn't the electric go off when the water goes off? ?


    However, if you must have it, and the doorway is two feet from the bath or shower basin (difficult to see how you could open a normal swinging door otherwise) you can put the switch there.


    More useful, of course, is the fan isolator, which can also be placed by the door, or even above it.


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