Discuss Trunking from CU (with fire-proof glands), does it need to be non-combustible? in the Security Alarms, Door Entry and CCTV (Public) area at ElectriciansForums.net

Welcome to ElectriciansForums.net - The American Electrical Advice Forum
Head straight to the main forums to chat by click here:   American Electrical Advice Forum

Mattja

-
Reaction score
10
For cables coming out of a CU and running where someone getting tools on and off a shelf next to the CU may knock against the cable if careless. I'm intending to give them some basic protection by putting trunking over them. The cables coming out the side of the CU go through non-combustible glands. However since the trunking will come right up close to the side of the CU it would of course still get extremely hot if there was a fire in the CU.

Would you suggest using non-combustible trunking, or having the trunking start where the glands end (so an inch and a bit away from the side of the CU, the glands are not metal so won't conduct heat too much), or not worry about it and use regular trunking?

If you think non-combustible trunking is the way to go where would you recommend getting it, and is there a non-metal option (mostly for ease of use)?
 
No the gland isn't getting hot, this is about the whole point of amendment 3 being so concerned with CU fires. If I've got a fully compliant CU but if there's something that might start a fire from the heat just outside it then it makes a mockery of having an amendment 3 compliant CU.
 
No the gland isn't getting hot, this is about the whole point of amendment 3 being so concerned with CU fires. If I've got a fully compliant CU but if there's something that might start a fire from the heat just outside it then it makes a mockery of having an amendment 3 compliant CU.

Is it in a dwelling?
 
If there was a fire inside the DB then you have serious problems even if you were to use galvanised trunking. Incidentally, instead of using glands and butting up to it you would use bushes and lockrings or flange the trunking into the DB.
 
Alright, thanks I'll keep that in mind. Don't really want to work on the CU as it's not one I installed and I've just seen the guy living there is keeping his toolboxes (full of sharp metal tools that could easily puncher a cable) on shelves right next to the cables. So I'm looking for a relatively quick and cost effective way to put some protection on those cables without rendering the fire-containment properties of the CU redundant.
 
What are non combustible glands? All you are required to do is maintain ingress protection ratings i.e IP2X and IP4X.
Well they're a bit unnecessary probably as old plastic glands would likely last till any fire had died out, but it's now possible to get non-metal glands made with non-combustible material, the point being that if the CU is non-combustible to comply with amendment 3 then it seems a good idea to extend that to the glands coming out the sides of it. The reason to go with non-combustible non-metal glands is that they're cheaper than the metal ones (and look nicer).
 
The reason to go with non-combustible non-metal glands is that they're cheaper than the metal ones (and look nicer).
Leaving aside Leesparkykent's valid point about there being no requirement for non-combustible glands, bear in mind that the Regulation only suggests ferrous metal (e.g. steel) as an example of non-combustible material. So non-metallic glands wouldn't meet this definition anyway.

It should be noted that nothing is actually non-combustible (even steel) - it simply requires sufficient heat!
 
OP if you put this reg (421.1.201) into context; in a consumer unit fire, the source of the fire might be bad workmanship and loose connections and allegedly the fuel for the fire is the insulated plastic enclosure of the consumer unit. Hence removing a readily combustible main source, would help prevent a fire propagating. Nothing else has changed it terms of cable entry etc. The reg is not applicable to previous installations, although some naughty sparks think it is :eek:
 
Leaving aside Leesparkykent's valid point about there being no requirement for non-combustible glands, bear in mind that the Regulation only suggests ferrous metal (e.g. steel) as an example of non-combustible material. So non-metallic glands wouldn't meet this definition anyway.

It should be noted that nothing is actually non-combustible (even steel) - it simply requires sufficient heat!
I actually brought this up the other day down at the NICEIC/ELECSA Tecktalk in Brighton the other day (bunch more scheduled for other parts of the country if you're interested). The big wigs there were of the opinion that although the regs suggested ferrous metal this was simply due to other sufficiently non-combustible materials being unavailable, and of about 2 dozen stands there one of them was showcasing a non-metal non-combustible gland kit designed for use with amendment 3 CUs. If that works for the NICEIC that works for me.
 
Anyway, thanks for all the feedback guys. From the on-topic replies I take it you wouldn't be too concerned about the material of the trunking outside the CU so guess I won't overthink this, cheers.
 
one of them was showcasing a non-metal non-combustible gland kit designed for use with amendment 3 CUs.
The reason they can get away with the non-metallic stuffing gland is because they fall outside of the Regulation anyway - not because they would comply with it if required so to do.
 
I actually brought this up the other day down at the NICEIC/ELECSA Tecktalk in Brighton the other day (bunch more scheduled for other parts of the country if you're interested). The big wigs there were of the opinion that although the regs suggested ferrous metal this was simply due to other sufficiently non-combustible materials being unavailable, and of about 2 dozen stands there one of them was showcasing a non-metal non-combustible gland kit designed for use with amendment 3 CUs. If that works for the NICEIC that works for me.
I thought it was/is the BS7671 we need to consult, not the NICEIC.
 
I thought it was/is the BS7671 we need to consult, not the NICEIC.


Unfortunately, there are a lot of professionals out there that believe what NICEIC says is law! It is so frustrating trying to re educate them. I just give up sometimes. Of course if you are a member of their scam, then you need to comply with their rules, even if they are bonkers!!

Jay
 
So long as your work is compliant with the relevant standards their own little rules can be dismissed.
 

Reply to Trunking from CU (with fire-proof glands), does it need to be non-combustible? in the Security Alarms, Door Entry and CCTV (Public) area at ElectriciansForums.net

OFFICIAL SPONSORS

Electrical Goods - Electrical Tools - Brand Names Electrician Courses Green Electrical Goods PCB Way Electrical Goods - Electrical Tools - Brand Names Pushfit Wire Connectors Electric Underfloor Heating Electrician Courses
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc
This website was designed, optimised and is hosted by Untold Media. Operating under the name Untold Media since 2001.
Back
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock