Discuss Protective earth bonding run externally, no mechanical protection in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net
A few years back I carried out a pre work survey and discovered a contractor had installed the main protective earth bonds clipped direct externally. When I questionned him, he assured me he was using a UV tolerant and weather-friendly cable that therefore complied. It was a brown cable which he then identified green/ yellow at the termination points, which were internal.
I'm currently on a project which requires a 10sqmm earth to be installed on the opposite side of a property and there's no feasible method of installation internally (solid floors, fininshed decor etc). Typically I would use 20mm black conduit etc, but this is an addition which has cropped up and I'll be swallowing the costs, so the earlier mentioned method seems attractive. It would be run at high level which reduces the risk of mechanical damage, but its not a cable I'm familiar with.
hahaha!! the previous contractor is talking crap...!! Main eathing and Bonding need to be G/Y through out there lenght not just identified at the ends..!!
nothing wrong with clipping direct as it is...!! but black conduit will look better!
There is no Regulation stating that a conductor wether it be earth, line or neutral, has to be the correct colour throughout, It is just prefered.
All that is required, is that the conductor is correctly identified at the terminations.
There is a Regulation prohibiting the use of a single core G/Y conductor being used for anything other than as an earthing conductor.
thats interesting...I've been advised by the almighty NIC that you cant do that due to the external influences. They will deteriorate the insulation quickly (which i have seen) and depending on where it is clipped, there is a mechanical damage issue!
BS7671 (not the NICEIC I know) requires a earthing conductor if buried to be a minimum of:
2.5mm² if protected aginst both corrosion by a sheath and mechanical damage.
16mm² if protected against corrosion by a sheath but not mechanical damage.
25mm² if not protected against either corrosion by a sheath or mechanical damage.
For earthing condctors that are not buried, BS7671 requires a minimum of:
2.5mm² if mechanically protected, and not part of a multicore cable.
4mm² if not mechanically protected.
As the minimum CSA for a bonding conductor is 6mm², and 6mm² is larger than the minimum 4mm² allowed without mechanical protection, then it follows that mechanical protection is not required.
As for the insulation breaking down, all the insullation is providing is protection against corrosion, and protection against corrosion is not required, unless the conductor is buried.
As usual I’m going back years. I ran a bare 19/.044 (about 21mm²) Hard Drawn (HD) copper around the outside of my house clipped with brass Ross Courtney’s after 6 months you couldn’t see it.
The ex had an inspection done last year at my suggestion (she has the house now). The guy that did the inspection apparently was confused. He could see the two ends of the conductor but looking outside the house he just couldn’t see it. The ex eventually pointed out the conductor running along the walls to him.
Following his tests everything was fine after the ex pointed out it was to 15[SUP]th[/SUP]/16[SUP]th[/SUP] edition. CU’s were replaced at my suggestion. The three lighting circuits threw him until I got the phone call and had to explain lighting rings. I’d warned her about shyster electricians but wouldn’t make a recommendation, it’s her property now, it’s her decision. (I’d known the guy that did it for 40 odd years, so was happy in my mind).
If you can get HD copper now it’s ideal for the job. 19/.044 fits perfect in a 16mm² crimp.
For 19/.044 read 16mm² now
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