17th ed: T&E or metal clad flex in a school

1capybara · Aug 20, 2012

Does 17th ed say I can wire a school in T&E? In the states you cant.

Can I wire a school in metal clad flex? In the states you can.

If none of the above are allowed, we will do it in EMT
which I believe you call thin wall. No, its not going to be done in Rigid. theres gotta be a better way, right?
Pls lmk, ok?

oldtimer · Aug 20, 2012

Its all to do with standard years ago they would only allow MICC cable and conduit as they built schools to last as for the current standards well I think anything goes. PS why do you want to know ?

Just to highlight on a personal note I drove past my old primary school last week and they had just demolished it it was a 1930 Art Deco design What a waste no doubt they will replace it with a cardboard box that will have to be replaced in 30 years.

poppypiesdad · Aug 20, 2012

you give it a whole 30 years , a primary school in abernerthy is being ripped apart due to shoddy workmanship (one of those ppi or ppl you know the council rents them ) all the kids are in a shiny new block of portacabins , which i may add look 100 time better than the crap they put up

Jamie

1capybara · Aug 20, 2012

this is for a proposed school in Afghanistan to be built
"within reason" to 17th ed. Which I interpret to mean that it doesnt have to be in rigid conduit. So I wanted advice as to what it should be wired with. We would use MC [metal clad flex] in the states when enclosed in walls, EMT if exposed on the surface of walls.

trev · Aug 20, 2012

I'd say they had a bit more to worry about there than building regs mate but if it's being done by a western project team the wiring type would be specified

Adam W · Aug 20, 2012

Wiring standards in schools seem to have fallen faster than in other areas. The original building of my old high school seemed to have been wired mainly in MI, which could have been there since it was built back in the 50s. Nowadays it seems anything goes - some of the modern wiring I've seen is IMO scandalous.

oldtimer · Aug 20, 2012

1capybara said:
this is for a proposed school in Afghanistan to be built
"within reason" to 17th ed. Which I interpret to mean that it doesnt have to be in rigid conduit. So I wanted advice as to what it should be wired with. We would use MC [metal clad flex] in the states when enclosed in walls, EMT if exposed on the surface of walls.

Yep I think you mean Kopex or as you say flexiable conduit that will be fine my opinion would be a 50mmx50mm or 75mmx75mm thats 2x2 3x3 trunking or box containment run it on the ceiling and drop off to lights , switches and power sockets I think you are on the right course here ie from the distribution fuse or circuit breaker board run the trunking at on the ceiling then drop or spur off via flexiable conduit that will be your containment system for the cable.
I take it this school is not too big is it

RogertheBodger · Aug 20, 2012

Oldtimer the stuff he's referring to is what used to be called Metaflex in the UK.
It may still be, haven't seen it around in a long time, it's a flex cable with a metal sheath that was unwound, like a pyro sheath, to expose the flex, I'm sure you remember it.

Hard to tell if this job is going to be done using American materials but installed to the 17th, could be a bit awkward.

needasparks · Aug 20, 2012

Adam W said:
Wiring standards in schools seem to have fallen faster than in other areas. The original building of my old high school seemed to have been wired mainly in MI, which could have been there since it was built back in the 50s. Nowadays it seems anything goes - some of the modern wiring I've seen is IMO scandalous.

That could because no one knows how to wire them anymore.
The installers don't have a clue and just rat the extra sockets and lights in and the schools go for the cheapest quotes.
I lost a few schools this term as i was overpriced by 1K on a 25K job, I was back to the bone on it as i really wanted the jobs so heaven knows what it will look like with less money on it. I think your term modern wiring is possibly a bit generous from the ones i've seen.

Adam W · Aug 20, 2012

I don't think it's because the installers don't know any better, I think it's because they're driven down on price.
School is wired in steel conduit when it's built, it comes to rewire it and the installer wants to install PVC conduit to save the school some money.
School shops around and finds an installer who will do it in T&E in basket for cheaper.
The next installer will do it in T&E on catenary wire and fix plastic end boxes directly on the ceiling.
The next installer will have mates and apprentices lashing T&E to the structural steelwork with cable ties, or when it looks like the job isn't going to get finished on time, wang the T&E across the top of the ceiling grid.

Who gets the job? That's right, the cheapest.

needasparks · Aug 20, 2012

You say that, i went to a school today to look at a job, extra sockets being fitted outside in mini-trunking and t&e from the ring.
The person fitting these was the air-con man. No wonder i never got the job. I did politely tell him his errors though, most likely fell on deaf ears.

1capybara · Aug 21, 2012

RogertheBodger said:
Oldtimer the stuff he's referring to is what used to be called Metaflex in the UK.
It may still be, haven't seen it around in a long time, it's a flex cable with a metal sheath that was unwound, like a pyro sheath, to expose the flex, I'm sure you remember it.

Hard to tell if this job is going to be done using American materials but installed to the 17th, could be a bit awkward.

Well I didnt mean to ask how to do this a cheaply as possible, I meant to ask how to do it right.
The choices being EMT [thin wall steel], MC [metal clad flex, picture attached], or T&E. Of these choices
T&E wouldn't be allowed in a school in the states, but this is a 17th ed job. The walls are studded out, so all
wiring in hidden in the walls.

Adam W · Aug 21, 2012

There's nothing in the 17th edition which says you can't wire a school in T&E, so people do it. We don't use the other 2 methods in the UK so BS7671 makes no reference to them.
If the ceilings are constructed of suspended tiles, t&e is often run in basket above, with socket and switch drops in conduit.

There are some here who would argue that it's not a 'proper job' unless it's wired in steel trunking and conduit, although they aren't methods you've mentioned. Steel conduit and low smoke zero halogen singles would seem to 'cover all bases'.

telectrix · Aug 21, 2012

a few years ago i did a new build school (to 16th). the council spec. was for all cables in T/E in basket above ceiling grid, with all drops in 20mm plastic conduit .

RISElectrical · Aug 21, 2012

All the school I have done, currently doing and pricing for the future all require galv conduit and singles. If this helps.

However have recently had 1 come out to re-tender due to costs and they have now allowed T+E to be used.

17th ed: T&E or metal clad flex in a school

1capybara

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oldtimer

poppypiesdad

1capybara

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trev

Adam W

oldtimer

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Adam W

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1capybara

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