James asks this question, which is about the earthing requirements for using SY cable. It has been answered by the NICEIC (Theme – Cables, Wiring and Wiring Accessories):
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Question: Can you please tell me the requirements for using SY cable on a three-phase or single-phase extension lead?
I use use one cable core for the earth and also bond the braiding, making a pigtail at the plastic sleeved ends. Some people cut the braiding short and just tape it up.
So can you tell me the correct method, as there doesn't seem to be a regulation on the subject?
Answer: We would always recommend using the correct gland for the cable in line with the manufacturer's instructions. There are glands on the market designed for SY control cables.
The galvanised braid is not considered suitable to use as a circuit protective conductor (CPC) for the cable, and it is also not considered to be an exposed conductive part.
The reason why it is not considered an exposed conductive part is that the cable meets the requirements of Regulation 412.2.4.1 of BS 7671 for protection against electric shock by means of the protective measure of double or reinforced insulation.
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