Earth Bonding

[thediynovice]

Hi all

Just read a thread on earth bonding which has forced me to ask my own question.

How exactly does Earth bonding work? What needs to be bonded and to what?

I know the earth wires for appliances on electrical items get connected, which lead back to the consumer unit earth, but what has this got to do with the water pipes?

Are ALL water pipes in a house connected to the consumer unit Earth?

Dumb question I know, but I don't know so thought I'd ask.

Cheers

 

[Daggit]

The water pipes are earth bonded at the sink, basin & bath, radiators, etc, so that if lightening strikes the house or there's an electrical surge or faulty wiring, the charge is dissipated through the earth continuity, sometimes back to the gas meter and gas pipes or through earth tags or to the electrical supply earth. Some flats/buildings have a 1mtr earth rod driven into the ground to create the earthing.

There is a greater danger around water, as this is a better conductor of electricity - water and electricity do not mix.

I don't think it is a good idea to earth back to the consumer unit though.

 

[mapj1]

A nice, if rather detailed link to why we earth stuff, here
http://www.mikeholt.com/documents/mojofiles/electricalearthingworldwide.pdf
nice diagrams though.

 

[thediynovice]

A nice, if rather detailed link to why we earth stuff, here
http://www.mikeholt.com/documents/mojofiles/electricalearthingworldwide.pdf
nice diagrams though.

Thanks mapj1, I'll take a look

 

[thediynovice]

Crikey !

What a complicated document!

 

[cmct]

If your house has metallic service pipes coming into the house then they must have an earth wire run from the consumer unit to them at a point "as near as possible to the point of entry of the services to the premises but on the consumers side of any insulating section (for water). For gas, the connection must be within 600mm of the service meter, or at the point of entry to the building if the service meter is external. The minimum cross sectional area of the earthing conductor is half that of the main earthing conductor for the premises.