Class 2 car park lights SWA badly installed

[timhoward]

I’m wavering a bit on this one.
RCD then B10 breaker. 1.5 sq mm 3 core SWA.
That runs underground in ducting, then up and feeds about 10 LED class 2 lights, with cable cleated to the wall, then under again in ducting and about 5 more lights with cable again cleated to the wall.

Now the thing is at the lights SWA glands haven’t been used, just grommets and silicon. I’m not concerned about water ingress as they fit well. But the steel armour isn’t joined anywhere. One core is used as CPC and continuous for whole circuit.
When I mentioned it I was told this came up before and they had got someone to improve it. Then I noticed that in both cases the light at the start of each underground run had been properly glanded with banjos and the armour connected to the CPC. So the two underground sections do have the armour earthed.
I feel like taking a pragmatic view that the bits that matter most are earthed, and the rest of the surface cleated cable could have been NYY-J or anything UV resistant, and it isn’t desperately unsafe that the armour is sitting there unearthed. As before the CPC is continuous (which felt like a miracle in itself with 15 class 2 fittings)

So I’m thinking this is a C3 at worst, mainly for wrong glands. I’m interested if there are safety aspects I’m missing though.

 

[westward10]

Does it comply with ADS under fault conditions, no.

 

[Rockingit]

Does it comply with ADS under fault conditions, no.

How so?? The circuit is a radial with a continuous cpc (assumes Zs, etc) on suitable CPD with RCD behind it.

 

[pc1966]

How so?? The circuit is a radial with a continuous cpc (assumes Zs, etc) on suitable CPD with RCD behind it.

I think @westward10 point is under damage/penetration the un-earthed armour would not cause ADS.

Just re-read it and seems there is RCD protection so it might not be fatal, but that is not ADS happening before the poor sod with a spade finds out.

 

[westward10]

How so?? The circuit is a radial with a continuous cpc (assumes Zs, etc) on suitable CPD with RCD behind it.

The armour is not earthed.

 

[Rockingit]

I think @westward10 point is under damage/penetration the un-earthed armour would not cause ADS.

OK.... now tell me why it needs to. I'm with @timhoward on this one

 

[pc1966]

OK.... now tell me why it needs to. I'm with @timhoward on this one

522.8.10 says if not in duct cables buried in the ground shall have earthed armour.

Again, should read more carefully as OP says in duct!

So probably C3 in the sense it is in duct and has additional protection, but it is still crap installation.

 

[pc1966]

This is an interesting point, it seems very bad practice to have a conductive armour that is not earthed as it makes a fault anywhere on the cable a risk everywhere, but off hand I don't know if there is a reg that states armour has to be earthed if the other requirements (protection in duct, 30mA additional RCD) are all met.

 

[Pretty Mouth]

I suppose the question is "Is the armour of SWA an exposed conductive part?"

Here's the definition in BS7671, save you getting the book out:

Exposed-conductive-part. Conductive part of equipment which can be touched and which is not normally live, but which can become live under fault conditions.

 

[pc1966]

I suppose the question is "Is the armour of SWA an exposed conductive part?"

Here's the definition in BS7671, save you getting the book out:

Exposed-conductive-part. Conductive part of equipment which can be touched and which is not normally live, but which can become live under fault conditions.

Also the question of whether it is considered a protective conductor (e.g. 411.3.2.1).

Obviously whoever installed it though not (if they thought at all) and as it is not used as a CPC then could be considered only the "Exposed-conductive-part" question. But to anyone working on such a system the (ab)use of the armour as a floating metal part does increase the risk of future mistakes.

 

[timhoward]

Thanks for the replies. I'm simply trying to quantify the risk in real terms for an EICR.

522.8.10 says if not in duct cables buried in the ground shall have earthed armour.

Again, should read more carefully as OP says in duct!

Yep, in ducting. I actually also said that the only two underground sections do have the armour earthed, so the poor sod with the spade should be ok, and for those bits ADS would happen. This happened as a result of the last EICR. They clearly stopped short of rewiring the lot.

The question is really about the rest of it, which is entirely visible and surface mounted on a wall and frankly SWA was overkill in the first place - it could have been anything UV rated. In general we don't usually design for impact protection of visible cables and impact seems the main risk here.

Taking the replies on board, the main concern seems to be the SWA becoming live in fault conditions. I'm struggling considering it an exposed conductive part, it's insulated as it enters the lights and is well taped up.

For me, chance of impact on wall mounted visible cables is a rather low risk. Risk of then subsequently getting through the armour and hitting a live is probably 1 in 3. Consequences of both these happening are severe as it will sit there forever with the armour live.
I think I'll sleep on it, as I'm not sure the initial two risks are likely enough for a C2.

 

[Rockingit]

Taking the replies on board, the main concern seems to be the SWA becoming live in fault conditions. I'm struggling considering it an exposed conductive part, it's insulated as it enters the lights and is well taped up.

From what you've said - the cable in question is not vulnerable to mechanical damage, is not in a duct and in fact is cleated to a wall. Further, it can't possibly be considered as having an exposed conductive part as the whole thing is sheathed - consider the construction of SY.

This is a classic case of just because something is unusual doesn't make it less safe!

 

[brianmoooore]

The above ground SWA with the unearthed armour is similar to where you come across 3&E used as T&E, with an unused, floating core. Bad practice, but not contrary to any reg.