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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 

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  • 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.
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  • 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.
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