Feed to flat in escape route - best option?

[Dartlec]

I have a job coming up where I likely need to replace old twin and earth (imperial size) feeding one, perhaps two flats in a 3 storey converted building.

The ground floor is a separate front entrance, the upper flats have a side entrance with stairwell, which is protected with smoke and EL, though not sure if a FRA exists, or if it counts as a protected escape route (there is an external metal staircase as well).

The current T&E is buried in the wall, but for ease/cost I'd like to surface mount from the meters (under the stairs at ground level) and up to the flat.

My current thinking is SWA surface clipped with Dline or Linian clips. Obviously there will be a suitable fuse in the meter cupboard to protect the run.

Anyone see an issue with that and feel an alternative is better or required (steel trunking for example)? I haven't worked with steel conduit or MICC so would rather this wasn't the job to start on...

If I go with SWA, should I be sourcing BS 7846 fire resistant cabling? If so, anyone know of a wholesaler that sells it by the metre?

 

[UNG]

It's always difficult to comment on jobs and sites you have never seen as to the suitability of a solution, I assume this is just a vertical run of cable which shouldn't pose any problems although where a cable comes up through a floor I do like to install some additional protection to prevent damage to the sheath at low level

 

[Dartlec]

Vertical from under stair cupboard on ground floor up through half landings on the first and second flight of stairs (wooden) and then horizontally across wall and into the flat..

I was thinking of possibly chasing a channel out to go from bottom to top of the mini stair landing it needs to cross vertically - could possibly fit some conduit in there as additional protection.

 

[UNG]

Seems a reasonable way to do it, rather than chasing a channel would it not be easier to install a 50x50 metal trunking

 

[Dustydazzler]

Some nice galv trunking is very on trend right now

 

[Petej999]

I have a job coming up where I likely need to replace old twin and earth (imperial size) feeding one, perhaps two flats in a 3 storey converted building.

The ground floor is a separate front entrance, the upper flats have a side entrance with stairwell, which is protected with smoke and EL, though not sure if a FRA exists, or if it counts as a protected escape route (there is an external metal staircase as well).

The current T&E is buried in the wall, but for ease/cost I'd like to surface mount from the meters (under the stairs at ground level) and up to the flat.

My current thinking is SWA surface clipped with Dline or Linian clips. Obviously there will be a suitable fuse in the meter cupboard to protect the run.

Anyone see an issue with that and feel an alternative is better or required (steel trunking for example)? I haven't worked with steel conduit or MICC so would rather this wasn't the job to start on...

If I go with SWA, should I be sourcing BS 7846 fire resistant cabling? If so, anyone know of a wholesaler that sells it by the metre?

What size is the current T AND E CABLE

 

[Dartlec]

What size is the current T AND E CABLE

it's the imperial equivalent of 16mm or so from memory

 

[Dartlec]

Seems a reasonable way to do it, rather than chasing a channel would it not be easier to install a 50x50 metal trunking

I was thinking surface mounted for most of the run, just the bit that passes through the wooden staircase in something. With a small van and just me I'd prefer not to fiddle with metal trunking, though may be that I need to bite the bullet and go for it...

Cost is certainly an issue since it's a joint freehold place so everyone has to agree.

 

[Dustydazzler]

I was thinking surface mounted for most of the run, just the bit that passes through the wooden staircase in something. With a small van and just me I'd prefer not to fiddle with metal trunking, though may be that I need to bite the bullet and go for it...

Cost is certainly an issue since it's a joint freehold place so everyone has to agree.

Pre premature collapse regulation I would have almost certainly done something like this in T4 trunking , but now I would bite the bullet and put up some nice galv trunking

 

[Dartlec]

Pre premature collapse regulation I would have almost certainly done something like this in T4 trunking , but now I would bite the bullet and put up some nice galv trunking

Would the linian or Dline clips work with SWA for premature collapse approval though? The only issue then is whether surface SWA is suitable in an escape route - There already is plenty of plastic trunking in the hallway for the EL and smokes, to be fair (not installed by me and been in well before the 18th and premature collapse )

 

[UNG]

Would the linian or Dline clips work with SWA for premature collapse approval though? The only issue then is whether surface SWA is suitable in an escape route - There already is plenty of plastic trunking in the hallway for the EL and smokes, to be fair (not installed by me and been in well before the 18th and premature collapse )

I quite often use plastic trunking with all round band or metal P clips fixing the cable inside it and have done for a number of years

 

[davesparks]

IWith a small van and just me I'd prefer not to fiddle with metal trunking,

What has the size of your van got to do with the design of the electrical installation.

I've recently completed a job which used around 60m of galv trunking and over 100m of galv conduit and I've got a Honda CR-V and that was also just me on my own.

 

[timhoward]

The ground floor is a separate front entrance, the upper flats have a side entrance with stairwell, which is protected with smoke and EL, though not sure if a FRA exists, or if it counts as a protected escape route

Protected escape routes are normally devoid of almost everything, made of concrete, with nothing at all combustible in them. If there's an external fire escape I'd be surprised if this was a "protected escape route". (See appendix 13)

Would the linian or Dline clips work with SWA for premature collapse approval though? The only issue then is whether surface SWA is suitable in an escape route

I'm not seeing any issues. Linian clips often support FP200 cables in normal escape routes.

 

[loz2754]

If it's not defined as such in a Fire Risk Assessment, then it's not a protected escape route.
And you've got until 27 September before you must work to Amendment 2.

 

[pc1966]

If I go with SWA, should I be sourcing BS 7846 fire resistant cabling? If so, anyone know of a wholesaler that sells it by the metre?

Would it need to be fire resistant cable (i.e. is it powering emergency support stuff)?
Superlec do it by the metre but smallest is 25mm:

https://www.superlecdirect.com/cables/fireproof-mains-cables-lszh/25mm-3-core-fire-resistant-mains-cable-lszh/

As a minimum I would look at LSZH SWA which they also do, and it thinner sizes (e.g. 16mm) and slightly cheaper, for comparison of same 25mm 3C:

https://www.superlecdirect.com/cables/steel-wire-armoured-cables-bs6724-lszh/bs6724-25mm-3core-xlpe-swa-lszh-cable-harmonised-black/

But the idea of using some steel trunking is very appealing as well. How many runs of SWA would you be looking at? With metal trunking you might get away with 16mm T&E as no cable penetration protection issues, assuming it meets other electrical requirements like VD and bond size, etc.