should fire alarm wiring be this messy ?

[Gary111]

Hi, Ive just had a fire alarm fitted, grade a, and interconnected mains detectors in each flat.

Its been done in trunking and looks messy to me, is this normal ?
thanks

 

[RF Lighting]

It’s all about the price.

If it was done on the cheap then this is pretty much the standard to expect. Compliant but ugly.

 

[Adam_151]

If it was done on the cheap then this is pretty much the standard to expect. Compliant but ugly.

You give cheap installs too much credit RF, I'd say theres a 50/50 chance at best that theres metal supports within that YT2!

 

[Gary111]

Thanks so there should be metal cable clips inside the trunking ?

 

[Gary111]

It’s all about the price.

If it was done on the cheap then this is pretty much the standard to expect. Compliant but ugly.

thanks, Its s grade a system with 3 call points , 4 heat sensors (one in each flat, and 3 smoke sensors in the stairs)
along with a mains smoke sensor and heat sensor interconnected within each flat. cost around £2k plus vat

 

[Risteard]

It really doesn't look that "messy" to me. For mini-trunking I would have said it's actually very neat.

 

[JohnW2]

It really doesn't look that "messy" to me. For mini-trunking I would have said it's actually very neat.

I agree, but it's obviously the fact that is IS mini-trunking that is the issue.

 

[Risteard]

I agree, but it's obviously the fact that is IS mini-trunking that is the issue.

Yes agreed, but obviously that was the agreed specification with the council, landlord or whoever.

 

[Gary111]

i had a look theres no metal supports in the trunking

 

[Risteard]

i had a look theres no metal supports in the trunking

It may not necessarily be every fixing. It only needs to be sufficient to prevent premature collapse of the wiring system in the event of a fire. So for a cable running through a masonry wall at either end, it may only need one or two in the middle of the run to prevent premature collapse.

Or, of course, it might be that none were used. In which case there's a problem.

 

[Adam_151]

It may not necessarily be every fixing. It only needs to be sufficient to prevent premature collapse of the wiring system in the event of a fire. So for a cable running through a masonry wall at either end, it may only need one or two in the middle of the run to prevent premature collapse.

There's a school of thought that being a fire alarm it requires more than that(and has done for much longer than general wiring has). Obviously to comply with BS7671 it requires metal supports to stop it collasping, for which the odd one or two would be sufficient, but BS5839 require the cables to be fire rated in order that the system keep working in a fire situation, now, unlike Pyro, fire-tuff does burn, but I understand it burns in such a way that it chars and the charred remains of the insulation remains in place separating the conductors, if it was exposed to flexing etc then this drops out the way, the conductors can short and the bells / sounders stop. I understand the standard for the cable gives maximum spacings for both horizonal and vertical runs in order to maintain its specified fire performance....

 

[Risteard]

There's a school of thought that being a fire alarm it requires more than that(and has done for much longer than general wiring has). Obviously to comply with BS7671 it requires metal supports to stop it collasping, for which the odd one or two would be sufficient, but BS5839 require the cables to be fire rated in order that the system keep working in a fire situation, now, unlike Pyro, fire-tuff does burn, but I understand it burns in such a way that it chars and the charred remains of the insulation remains in place separating the conductors, if it was exposed to flexing etc then this drops out the way, the conductors can short and the bells / sounders stop. I understand the standard for the cable gives maximum spacings for both horizonal and vertical runs in order to maintain its specified fire performance....

I wasn't suggesting that it shouldn't be FP inside the mini-trunking. We were talking about cable supports.

That said there is a difference between BS 5839-1 and BS 5839-6 and for Categories/Grades of systems. A Part 6 system can be wired in the same cable as the rest of the installation generally speaking.

For a commercial system we would typically have 25mm steel conduit drops to the sounders and call points etc.

 

[RF Lighting]

My local Morrisons supermarket is currently having a new fire alarm installed and they are using 25mm PVC conduit drops with white painted steel spacer bar saddles to the call points and repeater panels.

 

[danechip]

Mine...

 

[mattylad]

eek!