lights / bonding in bathroom

[Adam_151]

Yes, copper pipe can be used as a bonding conductor as long as electrically sound (no plastic fittings in it or such) so its the same bit of copper pipe is T-ed off to go to your toilet, from the pipe that feds the sink, no point in bonding it twice

EDIT: Very good source here: http://www.niceic.org.uk/downloads/NL139supp.pdf ,on bathroom bonding, and zoneing

 

[sijaysee]

thanks adam

 

[Bazdaa]

As he bravely places his head under the guillotine!

Why run the earth to the light switch, instead of running it directly to the main bonding pipe ie the mains water pipe in the basement, where I believe the cosumer unit is also bonded to.

Bazdaa

 

[Spark123]

Because you need to bond together the extraneous conductive parts (pipework runs etc) together and to all exposed conductive parts such as the lighting circuit, electric shower, heaters etc.
The water pipe (copper) at the point where it enters the installation should be bonded to the MET.

 

[Bazdaa]

OK, lets keep this simple, cos I'm a simple kind of person!

Now I would expect that the shower, lights ect, are already earthed as part of that respective circuit.

So with that in mind, can you not just know what I queried above?

 

[Spark123]

The idea of supplementary bonding is to establish an equipotential zone which reduces the risk of electric shock, i.e. a zone where all exposed conductive parts are at or about the same potential.

 

[Bazdaa]

Thanks, I need to investigate this further. Perhaps when I go on my Part P course

 

[sijaysee]

come on bazdaa ......keep up!!

 

[Bazdaa]

I know, I know. I'm trying.

 

[baldelectrician]

Here's a litltle something for reference,

http://www.baldelectrician.com/host/bathroom.pdf

from my website.

 

[Adam_151]

The point of supp bonnding is to ensure a sound electrical connection between items with have the potential to introduce a voltage into the bathroom, in order to make sure they have the same voltage, thus making a shock from touching separate items an impossibily.

You light might be connected back to the fusebox by 20m of 1mm², the earth going through serveral roses where there is a potential for bad connections, before going to the CU, and to the MET, where the main bond is connected, which goes to the water, then thiswaterpipe might have a pushfit join in it, etc, etc, get the idea, and all this will have a resistance higher than a piece of 4mm² running round your bathroom.

No need to band your soap dish, toothbrush holder, or the blade on your disposable razor because there is no way then can introduce a potential

 

[sijaysee]

only thats a little misleading. (the example from onsite guide from baldelectrician)from that it looks likes you need cables everywhere whereas you only need to go from the pipes to shower to lights to heater to fan etc. whats the point cross bonding the basin and the bath and the shower if they are the same pipes? also if the bath has a panel which is fixed and needs, for example, a screwdriver to remove it , then you dont need to bond it (unless the bath is metal). This was the point i was trying to make but i just got called incompetent!!

 

[Adam_151]

I can only see one bond thats been duplicated, the hot and cold are bonded together both at the sink and at the bath, can't see any issues with the rest of it

 

[Bazdaa]

Damit, damit,

So bonding the bathroom towel rail, and copper pipes back to the Water is not correct. When all I had to do was go to the lighting circuit, in the bathroom? Damit.

Problem is, it's all tiled up and painted. So now I'm gonna have to hack into the wall to bury the cable.

 

[sijaysee]

so what would you consider the most dangerous? doing it the way bazdaa did it or not doing any bonding in the bathroom?