Or that it complies to an earlier version of the standard that pre-dates the need for such markings.

Perhaps, but at the moment, the way things are (and the way BS 7671 is written), we can assume by default that older equipment is safe for bi-directional use. Manufacturer's data not always being available for obsolete devices (especially where the manufacturer may be ceased trading or had their name bought out by a Chinese supplier). Probably not a too unsafe assumption - since the old vanilla MCB or RCCB design is normally happy either way around.

   - Andy.

Or that it complies to an earlier version of the standard that pre-dates the need for such markings.

Perhaps, but at the moment, the way things are (and the way BS 7671 is written), we can assume by default that older equipment is safe for bi-directional use. Manufacturer's data not always being available for obsolete devices (especially where the manufacturer may be ceased trading or had their name bought out by a Chinese supplier). Probably not a too unsafe assumption - since the old vanilla MCB or RCCB design is normally happy either way around.

   - Andy.

AJJewsbury said:

Perhaps, but at the moment, the way things are (and the way BS 7671 is written), we can assume by default that older equipment is safe for bi-directional use.

Could you help us by explaining  how you came to that conclusion?

I was thinking of the wording of the NOTE to 530.3.201 - which seems to say to me that no marking of devices to the standards mentioned in Appendix 1 always implies bi-directional. e.g. Section 531.3.3 calls up "BS EN 61008 series" and appendix 1 lists "BS EN 61008" without any date qualification - which I think could be read as the NOTE applies to any version of BS EN 61008 - even pre 2017 ones.

I suppose you're going to point out that the more specific standard references in Appendix 1 are all date stamped though (e.g. BS EN 60898-1:2012+A12:2017) -  and so the NOTE could be read as applying on to that version ... so maybe there's some ambiguity there...

   - Andy.

AJJewsbury said:

I was thinking of the wording of the NOTE to 530.3.201 - which seems to say to me that no marking of devices to the standards mentioned in Appendix 1 always implies bi-directional. e.g. Section 531.3.3 calls up "BS EN 61008 series" and appendix 1 lists "BS EN 61008" without any date qualification - which I think could be read as the NOTE applies to any version of BS EN 61008 - even pre 2017 ones.

The NOTE itself says 'standards as listed' so it could be argued that the assumption is only valid for the dated version as listed.

As far as I know, the standards referenced for RCDs, circuit-breakers, RCBOs and AFDDs that bear the same reference have always had the requirement since the , although not all versions of predecessor British Standards (with a different reference number) did. However, there may be an inadvertent reason marking is not present (see below).

AJJewsbury said:

I suppose you're going to point out that the more specific standard references in Appendix 1 are all date stamped though (e.g. BS EN 60898-1:2012+A12:2017) -  and so the NOTE could be read as applying on to that version ... so maybe there's some ambiguity there...

I would not even go there ... see above, perhaps also 511.1 and the fact that it can only be the intent that a version of a standard pertains to the referenced versions of standards it references, but would also point out the following:

• BS 7671 does not apply to products themselves, only their selection. A NOTE in BS 7671 cannot dictate what is and has been in product standards.
• A standard cannot be 'interpreted' by another standard. Only a court can interpret a standard. The NOTE is to be taken for what it is ... a note for you to check elsewhere, something that's recommended (but you are still responsible for conformity) etc.
• An error could have been made by a manufacturer, or for a particular batch of products, or the marking may have been inadvertently removed. Looking for the absence of something is never a good way to 100 % verify something. It would still be an assumption?

gkenyon said:

or the marking may have been inadvertently removed

Deliberately, even.

I must say that no markings = bi-directional seems most unsafe. Presumably, at one time, nobody even thought about it.

I must say that no markings = bi-directional seems most unsafe.

Presumably it's an attempt at consistency and backward compatibility - since the original passive RCD designs (with the test button connected between N on one side and L on the other) we naturally reversible - and as most designs were used both in the UK and Continental Europe - where the convention for CU layout is the reverse of ours - with usually the bus-bar (or lots of wire links) above the devices and the outgoing connections below, there would have been a natural market pressure to allow devices to be connected ether way around (not that that's precisely the same as having power on both sides when the device is open, but that's another debate...)

   - Andy..