On 27/03/2019 16:33, ARW wrote:
On 27/03/2019 14:22, Robin wrote:
On 27/03/2019 13:24, Tricky Dicky wrote:
Read Adams reply in the "Running cables into trunking from CU". It's
the same issue.
Richard
Bugger, I somehow missed that thread.Â* It suggests I ought at the very
least to have drafted to steer people towards use of intumescent
sealant as "good practice".
I am sure the installation instructions on some metal clad CUs state
that the fire rating of the CU must be preserved.
I always used to silicone up the top entry of the plastic CUs I fitted.
Now I use fire mate etc.
I did have a quick look for manufacturers' instructions but all I found
was a rather fluffy Wylex/Crabtree note that repeated the IET line and
then went on to (as I read it) "sell" their intumescent add-ons without
actually saying they needed to be used[1]. But I can well believe some
go further now so it all points to pointing people to use
intumescent/fire rated seals. I'll have another go later.
[1]
G from
https://www.electrium.co.uk/media/20...ccessories.pdf
"The cable installation entry method shall, as far as is reasonably
practicable, maintain the fire containment of the enclosure. This can
generally be achieved by the installer ensuring that the cable access
holes they make in the enclosure do not leave gaps greater than:
1.0mm for the horizontal top surface and
2.5mm for all other surfaces
The installer could for example, select as they deem appropriate;
trunking, conduit, cable gland or cable entry accessories to minimise
the opening around the cables. For rear cable access, the minimum number
of rear knockout(s) shall be removed to accommodate the cable(s).
However, customer questions remain as to what further steps could be
taken to ensure that the necessary cable entries do not undermine the
intention of this new and important fire safety requirement.
Intumescent material when exposed to heat rapidly
expands and fills the surrounding area effectively
smothering fire and preventing spread by
extinguishing flames.
The Crabtree Solution
Working with a leading UK manufacturer of
intumescents, Crabtree have introduced the CRFS
range of intumescent material strips which fit inside
the consumer unit (self adhesive). If this intumescent
strip is exposed to heat the fire resistant €śchar€ť flows
around the cables filling the enclosure smothering the
fire by reducing the oxygen supply further, so
extinguishing the fire at source."
--
Robin
reply-to address is (intended to be) valid