Earthing metal conduit

[GrahamGKD]

What are the regulations for earthing galvanised conduit and cable trays please? What weight of earthing cable should be used? Is it fair to assume that conduit connected to metal clad sockets are effectively earthed via the socket back box and what method should be used where a conduit runs to a plastic fitment (e.g. a 16A industrial socket)? I presume every last part of the system needs to be bonded to earth?

Graham.

 

[mike os]

my understanding would be yes, needs earthing unless protected by RCD or RCBO

 

[GrahamGKD]

...all of the supply is protected by a RCD.

Graham.

 

[superls]

all metal conduit should be bonded to earth as i believe it

 

[brightspark]

]any cables that run in steel conduit must be suplied with there own seperate earth conductor to suit the instalation and not rely on the casing. if its a ringmain they would be a live neutral and earth cable run round the circuit conecting into each socket. a short earth link must go from each socket to the metal backbox. if cable trays are used they must be bonded[ back to.distribution board along with ay other metal framework of the building .cable sizing dependant on the instalation mainfuse. size minimum 10.omm earth bond 16mm from meter to db

 

[brightspark]

earthing arangements

 

[GrahamGKD]

Cheers all and Brightspark. All of the wiring is twin and earth so no problem there. All of the back boxes are bonded. Just need to bond the odd bits of conduit which don't terminate at a metal box - would you use the same kind of straps that are used for water pipe? Also need a bond to the cable trays but that should be simple enough.

Cheers,

Graham

 

[brightspark]

you can use earth straps to bond the conduit yes