just a simple question

[plumbit]

If the earth cables aren't connected from cu to the water and gas inlet pipes does that mean no electrical work to the rest of the building can go ahead.

 

[WarrenG]

If the earth cables aren't connected from cu to the water and gas inlet pipes does that mean no electrical work to the rest of the building can go ahead.

It means it needs to be sorted ASAP. Would be a code 1 on a PIR Requires urgent attention

The earths by the way should be connected via the main earthing terminal.

 

[dazza69]

Are you saying that the main equipotential bonding conductors can't go back to the CU? WarrenG!

 

[WarrenG]

Are you saying that the main equipotential bonding conductors can't go back to the CU? WarrenG!

Why would they want to go back to the CU and then back via the main earthing terminal for the earth path?

 

[dazza69]

Wot if the main earth comes off the supply and straight into the CU with no external main earth terminal. Cant you use the bonding terminals inside the CU?

 

[WarrenG]

Wot if the main earth comes off the supply and straight into the CU with no external main earth terminal. Cant you use the bonding terminals inside the CU?

Its a good point but if you lost the main earth at the CU and the main equipotential bonding conductors were connected in the CU you have still lost your earths. And if an earth fault occurs then the metal work could become live

The idea is to bring all metal work to the same potential. If connected at the main earth terminal they still have a direct connection to earth (i.e. same potential as earth) if the main earth was lost at the CU.

I hope this garbled text makes sense.

 

[Spudnik]

Interesting point Warren, however, regs wise, main bonding is permitted to be connected to the CU providing they can be 'easily' disconnected for testing.

The new G.E. boards have an earth link that separates the main earth at the CU from the rest of the bar so Ze can be measured without bonding and earthing influencing the reading.

Good point about M.E. becoming disconnected tho.

 

[WarrenG]

Interesting point Warren, however, regs wise, main bonding is permitted to be connected to the CU providing they can be 'easily' disconnected for testing.

The new G.E. boards have an earth link that separates the main earth at the CU from the rest of the bar so Ze can be measured without bonding and earthing influencing the reading.

Good point about M.E. becoming disconnected tho.

Haven't seen them G.E. boards will have to take a look.

 

[Spudnik]

Haven't seen them G.E. boards will have to take a look.

http://www.gepowercontrols.com/eu/r...er_unit_UK_final2_and_17th_wiring_edition.pdf

Carp PDF. you have to scroll around a bit!

Not too bad on the quality either.

Just fitted one a couple of weeks back (4+5+5 i think) and it was only about 50 quid including 10 MCB's!

 

[dazza69]

Wot if you you lost the main earth at the MET? Its all ifs and buts! As long as the main bonding is in place and correctly connected to the main earth so that everything is at the same potential then i don't see as it makes any difference where the connections are made - MET or CU!

 

[WarrenG]

Interesting point Warren, however, regs wise, main bonding is permitted to be connected to the CU providing they can be 'easily' disconnected for testing.

I have come across it in older installations but have always been under the impression that its better to use the MET for connection (if available) and seem to recall something about bonding close to the suppliers earth.

http://www.gepowercontrols.com/eu/resources/literature_library/catalogs/residential/downloads/gc_Consumer_unit_UK_final2_and_17th_wiring_edition.pdf

Thanks for the link! Who supplies them any of the main boys City, Edmunson, Newy, RS? Good price by the sounds of it!

Wot if you you lost the main earth at the MET? Its all ifs and buts! As long as the main bonding is in place and correctly connected to the main earth so that everything is at the same potential then i don't see as it makes any difference where the connections are made - MET or CU!

Like you say Daz its all ifs and buts. As I have said above I have come across it in older installations and have always been under the impression that it better to connect at the MET. It may just be a case of preference for ease of access? Might be a Regulation look up query.

 

[dazza69]

I do agree Warren it is better at the MET if available and easily accessible but unfortunately that's not always the case. Will have a look at the regs thought just to check.