Wiring a shower

[stanbesida]

The sleeving on the live feed from the shower unit burnt out on the pull switch and it burnt the switch so I got a replacement switch. The switch which I have removed had 2 earth connectors but the one I am replacing it with has only got one earth connector, this wouldn't be a problem if there was only 2 earths but for some reason there are 2 extra earths and I don't know why they are there. I have 10 ml cable coming in from the mains plus an extra earth lead, I also have 10 ml cable which I am replacing coming in from the shower unit but this also has an extra earth wire coming into the switch which makes 4 earths. My question is, DO I NEED 4 EARTHS COMING INTO THE PULL SWITCH OR WILL THE EARTHS IN THE 10 ml CABLE SUFFICE? I have also been informed that the 10 ml cable must be kept really tight so that there isn't any loose cable, but I thought you should leave enough slack so that it can be connected to the switch easily, without having to struggle to fasten the wires inside it. Thanks in advance for everybody's help

[The Builder]

The other earths sound like secondary earth bonding Stan ...................... not strictly necessary now as showers should be protected by an RCD :o)

[stanbesida]

Thanks for your help, I didn't really think that it required 4 earths but I though I would check to be sure. John

[The Builder]

I should have made that clearer Stan ................... do check to see that the shower is RCD protected ............. if not, it would be good to fit one, or the secondary earthing would have to stay.

[beso]

If you don't know what to do the you should not be attempting this. Indeed the earth resistance should be tested after installation.

The extra earths are to reduce the resistance to ground due to the high vulnerability of a person in a hot wet environment. The skin is very conductive in this situation and electrocution is much easier.

Whoever told you to make the earth cable tight is an idiot. Any earth should always be the slackest lead to ensure that it is the last to break if the leads are stretched.

[scotman]

I can't comment about the earth connections but I would always leave a reasonable amount of slack in the cables so that it its easier to make all the connections.

[trevorjones]

I realy think for safety's sake you should get a qualified electrician to do this connection for you. Just think of the consequences if you get it wrong.

[Tweed]

These days the regulations go overkill on earthing.
The extra earths are probably bonding as explained, but not to reduce the resistance, but to reduce the time it takes for the RCD to trip should there be a fault, as they should be connected to the nearest earthing point (usually hotpress). Totaly unnecessary IMO, but it keeps someone in a job and they want to keep it that way.