However, a consideration is also that we need to protect electricians going about their work. A brass gland won't do this, unless insulation (or some other form or barrier or enclosure) is used.

Careful... same issue could arise during the process of connecting a bond to an extraneous-conductive-part or the cable to the MET or or the MET to the DNO's earth terminal - and we don't insulate any of those....

   - Andy.

AJJewsbury said:

Careful... same issue could arise during the process of connecting a bond to an extraneous-conductive-part or the cable to the MET or or the MET to the DNO's earth terminal - and we don't insulate any of those....

Careful indeed. Suitable protective clothing ought to be worn, particularly with the risk of either diverted neutral currents or (and I wouldn't recommend doing it when he installation is energised, but to illustrate) protective conductors currents.

We are not, however, talking about connecting or removing bonding, but something else ...

gkenyon said:

if something available for testing is needed, provision of an insulated tail to a suitable 4 mm shrouded test terminal (all insulated), and suitable labelling, would be a better approach ...

Hi Graham, do you mean an armour strand when you say tail?

I am thinking that the PVC bedding surrounds each strand so that none of the strands are touching the ones next to it.

So taking a continuity reading between the source and your test point would give a much higher reading than you would get from if the strands were made off into for example a brass gland and the reading was taken from there. Or if the likes of a jubilee clip were used, along with plastic glands.

OlympusMons said:

Hi Graham, do you mean an armour strand when you say tail?

Possibly, but this will be quite difficult to achieve. Somehow, the armour needs to be terminated in a suitable gland, and from this a copper conductor 'tail' can be brought out for testing.

My preferred method would be traditional SWA brass gland into 'gapping tube', with tail brought from the brass gland, and some suitable insulation or barrier(e.g. cold-shrink sleeving) over the gland.

Have you come across the SWA storm glands? rated IP68, Plus, there’s no need for a shroud, It works with various cable types, including armoured, non-armoured, SY, and CY braided cables. It’s non-corrosive and UV stabilised and zero-halogen.Each pack comes with EarthingNuts

Yes, but how do these  protect electricians from simultaneous contact? You can still get at the brass armour termination inside the enclosure.

Hi Graham. Would Providing a warning label on the enclosure to alert personnel of potential dangers. This warning label serves to remind electricians and other personnel that, despite the requirement of a tool for lid removal, there remains a risk of exposure to live parts, such as the brass armour termination inside the enclosure. This is similar to the expectations when dealing with terminations that do not meet IP2X standards, where direct contact with live parts is possible.

AMK said:

Hi Graham. Would Providing a warning label on the enclosure to alert personnel of potential dangers.

Yes, but the CDM Designer would be advised to follow the Principles of Prevention ... and Hierarchy of Controls.

Under the Principles of Prevention, 'combat risks at source' is number 3 on the list ... providing instruction is the very last item. It is reasonably practicable to combat this risk by providing inexpensive insulation (although a warning notice of the folly of its removal without due consideration might also be practicable).

Under the Hierarchy of Controls, we should consider, in the following order:

1. Elimination (physical separation)
2. Substitution (why have two earthing systems in the first place?)
3. Isolation (provide insulation or barriers as discussed)
4. Engineering controls (possibly not relevant here)
5. Use of PPE (and this would follow warning if you've not isolated the hazard, and would require warning signs).

It wasn’t that long ago, in 2017, when professional guidance stipulated that at remote buildings, the SWA cable should be terminated at the remote distribution board or consumer unit using a plastic stuffing gland, rather than the conventional metal SWA gland. The SWA armour should be trimmed back beneath the cable sheath within the plastic gland to ensure it remains inaccessible. However, current discussions suggest that this approach may no longer be considered sufficient ?

AMK said:

The SWA armour should be trimmed back beneath the cable sheath within the plastic gland to ensure it remains inaccessible.

Given that a tug on the cable (unless there's a cable restraint) can remove it, and we know sheaths and insulation do move slightly ... It does seem like it may be OK, but the devil is in the detail.

The issue regarding pulling the cable with a stuffing gland is why in rail and airport infrastructure wiring, we used to use use plastic gland adaptor tubes, and sleeving). This is not new ... I'm going back to the 1990s.

AMK said:

However, current discussions suggest that this approach may no longer be considered sufficient ?

Well, the information in this thread is out there now, so that approach is perhaps not 'state of the art'