trunking as earth

solo2771 · Jan 21, 2011

Am I right in thinking trunking(4") shouldn't be used as the only form of earthing? as I am seperating the supply meters for 2 floors in an commercial building and there is no earth going up to the first floor supply not even connected to swa armourings.

nickblake · Jan 21, 2011

no it shouldnt be used as supply earths a seperate earth must be provided either by the armour if its size is acceptable for the purpose or a seperate earth , so you need to put one in

netblindpaul · Jan 22, 2011

nickblake said:
no it shouldnt be used as supply earths a seperate earth must be provided either by the armour if its size is acceptable for the purpose or a seperate earth , so you need to put one in

Sorry that is just wrong, you need to check your regs.
Trunking is OK as cpc as long as it meets the requiremetns of BS7671, there is no need for a dedicated seperate cpc conductor.

IQ Electrical · Jan 22, 2011

The OP needs to be more specific in what is actually being done, is he talking about a cpc or an earthing conductor?

Metal conduit can be used as an earthing conductor or cpc, trunking only as a cpc.

telectrix · Jan 22, 2011

IQ Electrical said:
The OP needs to be more specific in what is actually being done, is he talking about a cpc or an earthing conductor?

Metal conduit can be used as an earthing conductor or cpc, trunking only as a cpc.

that's what i thought. but even as cpc i would run a separate cable in the trunking where possible.