i have a friend who is installing a new light fitting into an alcove but its is a metal casing so has obviously has 3 wires from the fitting but the existing wiring within the alcove only has 2 wires. does this require an earth to be run from elsewhere?
earth
- Thread starter aberdeenpaul
- Start date
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You cannot fit a class 1 fitting to a circuit with no earthing. Most likely that the whole installation has no eathing on the lighting circuits so will need a rewire. Chack the Main bonding as well, chances are it'll be 6mm if its present at all. Should be 10mm for a TNS or TNC-S.
It's possible the wall-light drop was added on using 2-core cable, or some tw@ cut the cpc back because his light didn't need it.
Paul - what sort of cable is it, and is there access to the rest of the lighting circuit?
Paul - what sort of cable is it, and is there access to the rest of the lighting circuit?
I think, Ban, he was referring to the cable in the fitting when he said 3 wires.
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And I was referring to the cable in the wall....
Agree for TN-C-S but not for TN-S.
Page 27 OSG
Reread that reg, it states that the bonding shall be not less than half the csa required for the earthing conductor... The earthing conductor must be 16mm, half of which is 8mm so 10mm is approbate.
Required size, not sized in conjunction with 543-01-04 and table 54G.
See 543-01-03, calculation (adiabatic) is possible for sizing of main earthing conductors with a TN-S system. In many cases the *required* size will be 6mm or 10mm.
547-02-01 says that main equipotential bonding conductors shall be a minimum of 6mm and not less than half the size of the main earthing conductor so if the 543-01-03 gives us a 6mm or 10mm main earthing conductor then a 6mm main equipotential bonding conductor would comply.
See 543-01-03, calculation (adiabatic) is possible for sizing of main earthing conductors with a TN-S system. In many cases the *required* size will be 6mm or 10mm.
547-02-01 says that main equipotential bonding conductors shall be a minimum of 6mm and not less than half the size of the main earthing conductor so if the 543-01-03 gives us a 6mm or 10mm main earthing conductor then a 6mm main equipotential bonding conductor would comply.
Yjat last para hurt can you repeat it another way pls
Why not if they are of interest and cover generic discussions
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