INSULATED EARTHING CABLES AS LIGHTNING DOWNCONDUCTORS
INSULATED EARTHING CABLES AS LIGHTNING DOWNCONDUCTORS
(OP)
Hi ALL,
Anyone have experience in using PVC insulated green/yellow annealed copper conductor as lightning downconductor on outside of multilevel indoor substation for lightning protection? Any issues that should be considered?
Thanks
Anyone have experience in using PVC insulated green/yellow annealed copper conductor as lightning downconductor on outside of multilevel indoor substation for lightning protection? Any issues that should be considered?
Thanks






RE: INSULATED EARTHING CABLES AS LIGHTNING DOWNCONDUCTORS
The grounding conductor for CATV cable shields is required to be insulated by NEC 820.40(A)(1).
RE: INSULATED EARTHING CABLES AS LIGHTNING DOWNCONDUCTORS
Bare wire is chepaer too. But as jghrist mentioned there is nothing prohibiting it. But the insulated conductor has to be 'listed' for outdoor exposed use!
RE: INSULATED EARTHING CABLES AS LIGHTNING DOWNCONDUCTORS
RE: INSULATED EARTHING CABLES AS LIGHTNING DOWNCONDUCTORS
See NEC 2002, article 250.118 (1). It says "....insualted, covered or bare; and in form a wire, busbar or any shape"
RE: INSULATED EARTHING CABLES AS LIGHTNING DOWNCONDUCTORS
RE: INSULATED EARTHING CABLES AS LIGHTNING DOWNCONDUCTORS
These also include a test point located at about 1.5mtrs from ground level.
The bare GS / copper flats are the same as the ones laid on the roof of the building and thus there is no separate procurement involved for down conductors.
In case of Surge arrestors in the switchyards, the down conductor passes through a leakage current monitor and thus insulated cable is specified normally, for ease of connecting at the monitor terminals. This cable is typically specified to be insulated to 5kV.
RE: INSULATED EARTHING CABLES AS LIGHTNING DOWNCONDUCTORS
An insulated conductor will also build up less copper oxide as it ages which will make future taps easier and less likely to fail.
All black colored THWN (PVC) and XHHW insulation that is made in the U.S. is sunlight resistant. The vast majority (possibly all) or colored THWN and XHHW insulation is also sunlight resistant. There was an article in Electrical Contractor magazine about this issue and essentially any U.S. building wire that is waterproof is also sunlight resistant in order to avoid liability issues and to Keep It Simple Stupid.
Mike Cole