Regulation 521.10.202 - Wiring systems

[Scott Jacob]

just brushing up on the 18th edition before I take the refresher this week. Iv seen Regulation 521.10.202 which basically states cables need to be supported throughout the installation in such a way they do not get in the way in the result of a fire. Does this mean cable clips on ceilings / upper floors are not longer used due to them being plastic?

 

[*-jester-*]

It applies to all wiring systems as far as I know.

That's how I interpret it too but you wouldn't usually surface mount cables on a new domestic installation anyway would you?

 

[Spoon]

It applies to all wiring systems as far as I know.

Good to know I've read it right this time...

 

[davesparks]

Personally I have thought this to be somewhat puzzling, the whole requirements around this subject. Remembering this all came out of the greater London Fire fighter observations that there operatives were being electrocuted from live wires I suppose breaking and dangling and making contact.

This regulation has come about as a result of the deaths of firefighters who became trapped in cables which had fallen down in burning buildings.
The coroners in these cases made the recommendations.

Your post is the first I've heard of any electric shock incident related to this.

 

[goasis]

I think note 3 makes it reasonably clear, although I did have to check the meaning of 'precludes'!
You can't use non-metalic fixings as the ONLY means of support where cables are clipped to exposed surfaces, I take this to mean that above plasterboard (i think standard board is 30min fire rated?) it is fine to use plastic clips etc.
Think about old pubs with all the cables just clipped to the exposed joists etc - big no no now.
Non metalic trunking as sole means of support is not allowed - so must also use metal fixings within the trunking.

What's not so clear is if you can apply some common sense to this - knowing what the intention of the reg is (firefighter safety predominantly) so what are we saying about low level trunking, or even dado trunking around offices?

 

[Andy78]

Think about old pubs with all the cables just clipped to the exposed joists etc - big no no now.

Will be fine and will actually look quite neat if you resurrect the use of the humble buckle clip.

 

[*-jester-*]

What's not so clear is if you can apply some common sense to this - knowing what the intention of the reg is (firefighter safety predominantly) so what are we saying about low level trunking, or even dado trunking around offices?

Dado trunking... Very interesting point! Then you would only need to support the cables when they go over doorways for example.

 

[Andy78]

That's how I interpret it too but you wouldn't usually surface mount cables on a new domestic installation anyway would you?

Been to a job today where surface trunking will be considered due to the upstairs lighting needing rewired in a flat roof house.
Also done a few flats before with concrete floors and ceilings where surface trunking is the preferred option.
Wiring in domestic garages and outbuildings is usually done surface in trunking or conduit too.

 

[goasis]

Wiring in domestic garages and outbuildings is usually done surface in trunking or conduit too

true, ive seen and used the metal clips designed to go in trunking, whats the solution for plastic conduit?

 

[Spoon]

What's not so clear is if you can apply some common sense to this - knowing what the intention of the reg is (firefighter safety predominantly) so what are we saying about low level trunking, or even dado trunking around offices?

In my opinion, I would say that the reg also applies to this as well.
In fires, fire fighters hug walls. The reg is intended to stop entanglement. I don't think the fire fighters would be impressed if their feet were getting entangled in cables..

 

[Andy78]

true, ive seen and used the metal clips designed to go in trunking, whats the solution for plastic conduit?

Use metal. Metal saddles on plastic conduit have been used for years by fire alarm installers. You can get powder coated saddles to match PVC conduit too.
Also saw something lately at a local wholesaler trade event that was like a buckle clip for conduit, can't remember the brand though I'm afraid.

 

[cprfenom]

true, ive seen and used the metal clips designed to go in trunking, whats the solution for plastic conduit?

Galv saddles. You can get them in white and black now too

 

[Andy78]

While we are on this subject, what alternatives has the market spat forth to replace the use of plastic screw plugs ?

 

[GBDamo]

true, ive seen and used the metal clips designed to go in trunking, whats the solution for plastic conduit?

I've used Galv saddles with metal plugs to overcome this one.

 

[DPG]

While we are on this subject, what alternatives has the market spat forth to replace the use of plastic screw plugs ?

Wall dogs or whatever other names plugless screws go by.

 

[MFS Electrical]

Personally I have thought this to be somewhat puzzling, the whole requirements around this subject. Remembering this all came out of the greater London Fire fighter observations that there operatives were being electrocuted from live wires I suppose breaking and dangling and making contact. The puzzle for me is what happened to protection. A cable subjected to flames should surely cause the migration of conductive parts to short out and activate the protection for that circuit. So in a home 6242y or whatever similar type should start to melt and set off the MCB, why doesn't it?

I think it’s more the entanglement risk than the risk of electric shock Vort