electricalforum.nz

Is ordinary duty flexible cord suitable for ELV without an additional enclosure?

Just curious because of the fact that single insulation is suitable for ELV but it appears that ordinary duty flexible cord isn't suitable for installation wiring without an additional enclosure

This would make me think that OD flex with sheath would be non-compliant but if you stripped it it would become compliant, sounds like a technicality

Where did you get the idea that single-insulated conductors are suitable as installation wiring for ELV parts of installations?
When asking questions like this; it really would help if you quoted the clause(s) you are talking about.
3.9.7.4 , restricting flex used as installation wiring to HD only (for most cases), applies to both LV and ELV.

Apologies, as you said above and I agree 3.9.7.4 indicates HD flex only regardless of ELV or not

3.10.1.1 exception (e) indicates insulated unsheathed is suitable for EL

So that's what got me thinking

However, I've also seen 7.5.11.1 but that clause isn't very specific in what it does and doesn't overrule

OK; I see where you're coming from .

Technically all of "3000" applies to ELV as well as to LV, unless something in 7.5 specifically says otherwise.
However much of the Standard is written from an LV viewpoint (and almost all of it is written from an "MEN" viewpoint).
So I believe that you have identified an unintended effect of this; in that single-insulated cable doesn't have to be in a wiring enclosure if it's ELV - unless it's flex, in which case it has to be HD sheathed .
Almost certainly an oversight, on that the writers didn't consider that someone might use eg appliance wire (flexible conductor) or tru-rip for ELV installation wiring.

Yeah, I've seen you mention this a few times and it makes sense. I just wasn't sure if 7.5.11.1 meant that 3.9.7.4 didn't need to be applied for ELV systems

para 3 of 7.5.2 says that where no particular requirement is specified in this Clause (ie clause 7.5), ELV parts of installations must comply with other sections.
The "particular" parts of 7.5.11 are
(i) suitability of conductors and their insulation; and
(ii) relaxes need for "further" protection - but not for all cases, only where installation conditions don't "demand' it.
That's not very precise, and I don't think it can be stretched so far that it can switch off a direct statement that flex has to be both insulated and heavy-duty sheathed. Sheathing isn't "further" protection, it's part of the underlying conductor type.
However an argument could also be made the other way, along lines that single-insulated and unsheathed conductors are sufficiently "suitable" for ELV, and so is ordinary-duty flex.
I dislike the lack of clarity; but under NZ regime it's up to whoever certifies the work to be able to justify their decision.