Earth Wire

[Gleniw]

How do I know what size earth wire to be used for bonding. Is it down to the area?

 

[Spark123]

Main equipotential bonding is the bond between the main earth terminal (MET) and other incoming services such as gas and water on a copper pipe install.
The size of the main equipotential bonding is determined by the type and size of supply TT, TN-S, TN-SC (PME).
For PME you need to ask your electricity supply operator for this info.
For 100A TN-S with a main earth conductor of 16mm² the main equipotential bonding conductor needs to be 10mm²
For a TT the main equipotential bonding must be at least half the size of the earthing conductor (rod - MET) and not less than 6mm

Supplementary bonding is the cross connection of all extraneous & exposed conductive parts in a location giving rise to increased risk of electric shock such as a bathroom.
See http://www.tlc-direct.co.uk/Book/5.4.3.htm

 

[yai46]

As a rule using 4mm2 for cross bonding pipes in your bathroom etc.

Upto 100A main supply should be 16mm2 Earth.

Old 60/80Amp supplys will be upgraded in the near future to 100A so install 16mm2 regardless

 

[Gleniw]

Thank you very much.

 

[mattux]

hi

just another option

you can bond the water and gas in 1 length of 16mm cable, as long as the cable is not cut at any point.

hth

matt

 

[Spark123]

hi

just another option

you can bond the water and gas in 1 length of 16mm cable, as long as the cable is not cut at any point.

hth

matt

Why 16mm²?

 

[mattux]

hi

just another option

you can bond the water and gas in 1 length of 16mm cable, as long as the cable is not cut at any point.

hth

matt

Why 16mm²?

im not sure if you understood my post.

normally you would run a 10mm earth for the water and then another 10mm earth for gas. however it is acceptable to run a single 16mm to the water and then the gas(or viceversa) as long as the cable is continuous, ie not cut/broken anywhere including the first point of termination, in this case the first tenby.

matt

 

[Spark123]

Correct me if I am wrong, but is it not the type of supply (TT, TN-S, PME)which dictates the size of the main equipotential bonding cable to use? I am also struggling to find the reg which says the cable needs to be increased to 16mm² for looped instead 10mm² (providing 10mm² is the correct size for the type of supply).