If I have been using 6242Y twin and earth cable for regular lighting, can I use 6243YH three core and earth for two-way lighting? I know the H is for harmonised, but I don't know if there are any stipulations in the 18th Edition of the wiring regulations against installing harmonised and non-harmonised cables together.


1 Answer 1


Not all commonly used UK cables comply with the harmonised standards anyway.

UK flat PVC twin-and-earth (and triple-) cables should comply with BS6004.

I can't see any consistency with major suppliers listing either Y or YH type cables.

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