Singles in plastic trunking.

[SUNRAY]

Back in 2006 I installed some dimmers in our church hall and I believe the installation was compliant with the (then current) 16th edition regs. The church recently had an electrical inspection and have been told that the feed does not comply so must be replaced. The issue is that I used 16mm singles inside 3" plastic trunking and they want to replace this with SWA. I'm way out of touch with current regs as I have stopped doing that sort of work, but I looked at my old 17th edition and can't see what the problem is. Please can someone who is current with the regs tell me whether I screwed up originally or whether the regs have changed significantly since then. I know that wiring buried in walls has to be protected now a lot more than previously.

Section 522 is the relevant part

My initial reaction:

I'm not up to current regs either but I see no reason for any doubt if it was a 16mm² T&E clipped to the wall or 16mm² singles in plastic conduit.

I suspect it is just work creation scheme r us.com in action.

I can think of many installations of singles in plastic cable management, surely they can't be wrong... or can they?

 

[sarkyspark]

If the containment is continuous it would if been fine under the 16th. Now it would not meet requirements regarding preventing premature collapse in a fire which was required for escape routes in the 17th and for everything in the 18th.

 

[winston1]

Regs are not retrospective though.

 

[JohnW2]

My initial reaction: .... I can think of many installations of singles in plastic cable management, surely they can't be wrong... or can they?

Single-insulated live conductors within (adequately) insulating 'enclosures' of any sot are surely ubiquitous, and fully acceptable (e.g. CUs, accessories, many appliances and electronic products etc. etc.), aren't they? As mentioned in the passage you quoted, the one exception is when they are buried in walls, when there is also a requirement for mechanical protection and/or an earthed covering.

Kind Regards, John

 

[flameport]

plastic cable management

522 concerns external influences. Did they state which of the many items in 522 were relevant?

 

[SUNRAY]

Again my apologies I didn't make clear my OP was quoting another persons post on another forum/site. AIUI the info posted is all he has available other than in a later post he says at one point a short length of lid has gone missing. The reference to 522 AIUI is his attempt to work out where the issue is.

 

[JohnW2]

Again my apologies I didn't make clear my OP was quoting another persons post on another forum/site.

I wouldn't worry - that was totally clear to me, if not to everyone (that's why I referred to "the passage you had quoted").

It was really flameport's quoting (i.e. the attribution at the head of it) that was 'wrong'.

Kind Regards, John

 

[SimonH2]

Collapse in a fire can be dealt with by metallic fixings inside the trunking - e.g. a bit of perforated strapping and a couple of screws into the brick/block behind.
The only reasons I can think of for saying singles in trunking is non compliant would be :
1) If the trunking can be opened without the use of a tool. Some can, some can't, some can't except when it's getting on a bit and has been abused and the lidding hasn't been fitted properly.
2) The trunking and fittings (e.g. bends, tees etc) are not IP4X or IPXXD rated. So if you can push a (from memory) 1mm dia item of something like 100mm in through a gap then the cables inside have to be sheathed. It's really hard to do DIY mitre joints that fit that closely.
3) The trunking doesn't fit tight enough to enclosures so as to meet the IP4X or IPXXD requirements.

When I did some work in our church a couple of years back, I used the add-on IP4X kits from the (galv) trunking manufacturer. I think they are poor compared with making the trunking and fittings IP4X - but then they also have to consider backwards compatibility if they start altering the design.