Phase rotation

I agree, but I think the only Regulation does it not comply with is 134.1.1 (also perhaps 134.1.3 at a push).


To the best of my knowledge, the only Regulation outside Part 6 that mentions phase rotation is 463.3.3, which requires protection against phase reversal where required for safety.


Whilst verification is required in 643.9, a requirement for verification cannot in itself be transposed into a requirement for design and erection. Basically, you complied with the requirement to verify it (and came up with the answer that the phase rotation is not maintained).


What that means in the grand scheme of things in a particular installation where phase rotation is not important is, in my opinion, purely and simply poor workmanship, based on the fact that there is no requirement for phase rotation to be maintained in BS 7671, perhaps with the exception of conductor identification.

Graham,


I can't argue with your logic, but why is there a requirement to verify that the phase sequence is maintained if there is not actually a requirement to maintain it?


I fully agree with your last paragraph. The regulations are essentially about ensuring an installation is safe and if phase rotation is not important then the phase sequence has no impact on safety.

I suppose if they have 3 phase kit, it needs noting so nobody tries to fix it and damages something, but it is pretty small beer, and quite common in some parts of the world (hence all those plugs where you can flick a switch and swap 2 phases over.)

C3 or just a note and no action seems about right.

Can't argue with the question about why there's a requirement to verify it.


It's actually in IEC and HD 60364-6 as well ... I'm guessing (although it's only a guess) that it's seen as good workmanship - in BS 7671 the particular Regulations I pointed out in Part 1 - and therefore worthy of verification.


I personally can't see a reason to argue against checking for it, as it may cause an issue (maybe a safety issue) for installation of appliances later, some of which, such as laundry equipment, may connect via plug and socket-outlet, i.e. not part of the installation, but essentially almost "plug and play".


So, I think the converse question should be asked ... why is there not a requirement, say in Part 4, to maintain phase sequence throughout the installation?