Fitting consumer unit vertically

[ban-all-sheds]

OOI, what colours are your installation line conductors? (Ignoring 3-core cables for fans, 2-way switching etc)

 

[JohnW2]

OOI, what colours are your installation line conductors? (Ignoring 3-core cables for fans, 2-way switching etc)

As you might expect, 'a mixture' (and, yes, for what it's worth, there are labels to that effect!). It was obviously all red/black when I moved in, and a fair bit of that remains (although most of the imperial has now gone) but there's now also quite a bit in harmonised colours (installed during 2004, you will understand, or replacement of damaged cables during 2005-2013, or new cables on existing circuits thereafter!).

Talking of colours ... as I've illustrated before, my incoming neutral is red-insulated. Lucky I took those photos when I did, since the guy who changed the meter a few months ago covered up the evidence with grey silicone

Kind Regards, John

 

[stillp]

By the way chaps, 60439 was replaced by 61439 in 2009. Do try to keep up!

 

[JohnW2]

By the way chaps, 60439 was replaced by 61439 in 2009. Do try to keep up!

I think you have to blame that on the fact that BAS apparently has not got a BYB (Amd3)t. I had been writing about 61439-3 (and Annex ZB thereof) until, just after midnight last night, BAS quoted 530.3.4, seemingly from his BGB (i.e. Amd1) (hence 60439-3 and Annex ZA), and when I replied (and subsequently) I just followed what he had posted, without realising that I was doing that!

Kind Regards, John

 

[ban-all-sheds]

As you might expect, 'a mixture' (and, yes, for what it's worth, there are labels to that effect!). It was obviously all red/black when I moved in,

Pause there.

"Obviously all red/black"? Isn't there therefore an obvious lack of yellow and blue line conductors, and therefore an obvious lack of a 3-phase installation?

but there's now also quite a bit in harmonised colours (installed during 2004, you will understand, or replacement of damaged cables during 2005-2013, or new cables on existing circuits thereafter!).

Shame you could not have sourced red/black cable for the alterations

But (again ignoring 3C+E cables for fans, 2-way switching etc) did you use only brown for line conductors, or did you also use grey and black, on the grounds that yours is a 3-phase installation?

my uncertainty relating to my place as it is currently set up is that there is a single 3-phase meter, and that could well be taken to indicate that it was a single 'installation'.

Not sur that metering makes any difference. Returning to my hypothetical 6 flats, 1A, 1B etc - if all parties were happy for the landlord to pay the electricity bill and give the tenants unrestricted/unmetered supplies as part of their agreement, and each flat had a CU supplied from a switchfuse in the basement , would you regard the flats as 6 single-phase installations, or as them all sharing one 3-phase one?

 

[ban-all-sheds]

I think you have to blame that on the fact that BAS apparently has not got a BYB (Amd3)

I have.

So you'll all have to blame it on me, having searched for and found the text I wanted to copy & paste to save me typing it, not spotting the archaic standard reference. Sorry.

I even managed to create a post where I used both numbers, varying as I copied from different sources, and still not notice.

 

[JohnW2]

... Sorry. .... I even managed to create a post where I used both numbers, varying as I copied from different sources, and still not notice.

No problem. We've all ben there

Kind Regards, John

 

[JohnW2]

"Obviously all red/black"? Isn't there therefore an obvious lack of yellow and blue line conductors, and therefore an obvious lack of a 3-phase installation?

I suppose one could argue that - but, in any event, that was in 1987.

But (again ignoring 3C+E cables for fans, 2-way switching etc) did you use only brown for line conductors, or did you also use grey and black, on the grounds that yours is a 3-phase installation?

That is presumably essentially a rhetorical question (at least, you know the answer!). With the sort of exceptions you mention, all cables (other than distribution cables - as below) are T+E, and I'm not sure I would have been able to find black/blue or grey/blue T+E! Even the meter tails and distribution circuits are in red/black (insulated and sheathed singles). Whether any of that makes it three single-phase 'installations' in the eyes of BS7671, only "BS7671" could tell us! As I've already observed, their definition of "installation" is all but laughable, and certainly not helpful in this context.

Not sur that metering makes any difference. Returning to my hypothetical 6 flats, 1A, 1B etc - if all parties were happy for the landlord to pay the electricity bill and give the tenants unrestricted/unmetered supplies as part of their agreement, and each flat had a CU supplied from a switchfuse in the basement , would you regard the flats as 6 single-phase installations, or as them all sharing one 3-phase one?

Again, as you would be only too quick to remind me, it's not what "I would regard" that matters but, rather, how "BS7671" regards it - and there is not enough clarity for us to know about that.

I agree that the 'spirit' of what I have could be said to be that of three single-phase installations - but that's just my opinion, hence irrelevant. The uncertainty could probably have been avoided if 530.3.4 had talked about an installation that had single-phase protective devices (which I suspect is what they were thinking about), rather than a single phase "supply".

Kind Regards, John

 

[ban-all-sheds]

Again, as you would be only too quick to remind me, it's not what "I would regard" that matters but, rather, how "BS7671" regards it - and there is not enough clarity for us to know about that.

You say there is no "clarity", but I truly do not see how a DB/CU with only single phase devices in it, and only one phase going into it, cannot, along with the final circuits coming from it, be regarded as an assembly of associated electrical equipment having co-ordinated characteristics to fulfil specific purposes.

 

[JohnW2]

You say there is no "clarity", but I truly do not see how a DB/CU with only single phase devices in it, and only one phase going into it, cannot, along with the final circuits coming from it, be regarded as an assembly of associated electrical equipment having co-ordinated characteristics to fulfil specific purposes.

As I said, there is no clarity (particularly in relation to the definition of an 'installation'). Virtually anything could be regarded as "an assembly of associated electrical equipment having co-ordinated characteristics to fulfil specific purposes". Maybe I don't have 3 'installations', but actually 30, 100, or ..... ?

I could certainly argue that, for example, each of my final circuits satisfies that definition.

Kind Regards, John

 

[ban-all-sheds]

Have as many as you think you have.

Then count how many are 3-phase.

 

[JohnW2]

Have as many as you think you have. Then count how many are 3-phase.

You know the answer to that. However, as I said the BS7671 definition of an 'installation' is to vague that almost anything would satisfy it, and I haven't a clue what is 'intended'. At one extreme, as I said, I could argue that each of my final circuits was an 'installation' - but, at the other extreme, someone could argue that the totality of everything electrical within my house constituted 'an installation', and that one undeniably has a "3-phase supply".

Kind Regards, John

 

[ban-all-sheds]

However, as I said the BS7671 definition of an 'installation' is to vague that almost anything would satisfy it, and I haven't a clue what is 'intended'.

No, but I do not see that regarding one SP CU and its final circuits as an installation is so outlandish that one should worry about whether the regulations intend that not to be the case.

At one extreme, as I said, I could argue that each of my final circuits was an 'installation'

Oh that's not extreme. An FCU supplying a fan could be an assembly of associated electrical equipment having co-ordinated characteristics to fulfil specific purposes. 2 x 2-way switches and a length of 3C+E cable could also be.

but, at the other extreme, someone could argue that the totality of everything electrical within my house constituted 'an installation', and that one undeniably has a "3-phase supply".

They could.

But if they would not argue with as much conviction, and with as much logic, that the same applied to our small block of 6 flats, and that nobody there had their own single-phase installation but instead all had parts of one 3-phase one, then that would show how flaky and poorly considered their argument was.

 

[JohnW2]

No, but I do not see that regarding one SP CU and its final circuits as an installation is so outlandish that one should worry about whether the regulations intend that not to be the case.

I agree - that would not be outlandish at all.

However, nor would I consider it to be at all 'outlandish' to regard the entirety of the electrical 'system' within a single dwelling as 'an installation'. Indeed, I suspect that is how most electricians would think of it.

You seem to be uncharacteristically defending a situation in which BS7671 has woefully inadequate definitions.

Kind Regards, John

 

[ban-all-sheds]

No, I am not defending anything.

I agree - that would not be outlandish at all.

However, nor would I consider it to be at all 'outlandish' to regard the entirety of the electrical 'system' within a single dwelling as 'an installation'. Indeed, I suspect that is how most electricians would think of it.

Fair enough - consider that you have a single installation. OOI, which part(s) of it could be regarded as 3-phase?

Do you also consider that the small block of flats has a single installation? Or do you consider that there are non-electrical factors which can change multiple CUs on multiple phases (but only ever one each) from one installation to multiple, and back again? Are these factors defined anywhere? Is there any testing which someone could do to determine whether you have one installation or three? With the hypothetical flats, are there any tests which someone could hypothetically do to determine whether the building has one installation or six?