Gaps In Old Cus/fuseboxes Etc, Fire-retardant Silicone?

[Mattja]

This is fresh off the top of my head, but what do you guys think about having some fire-retardant silicone to seal gaps in old CUs to contain a potential fire within the CU (at least for longer)?

A good idea, or just going to leave fingers pointing my way if there ever is a problem with it? (Either with the silicone or the CU in general)

P.S. Silicone doesn't cause degrading of wire insulation it comes into contact with does it?

 

[Leesparkykent]

Some times its the only practical way to maintain IP ratings on older boards that have been butchered. Try to use something that's neutral curing like

http://www.toolstation.com/shop/p54145

 

[Midwest]

Are you trying to apply reg 421.1.201 to existing CU's? As far as I'm aware, I may be wrong, one of the original reasoning's for the reg, was to remove a potential fuel supply (i.e. plastic enclosure) to a ignition source within said CU.

Whilst I note that Wylex for example, are selling intumescent strip, to now 'contain' any fire with CU, that's not what the aforementioned reg states, i.e. the enclosure must be non combustible or in non combustible .....

Sealing with silicone would be one way of maintain IP rating, as Lee said, but not to contain a fire.

 

[hightower]

I asked my NIC assessor about this recently and he echoed pretty much what @Midwest has said.

 

[Dan]

Some times its the only practical way to maintain IP ratings on older boards that have been butchered. Try to use something that's neutral curing like

http://www.toolstation.com/shop/p54145

Or this from our sponsor

http://www.cef.co.uk/catalogue/prod...icone-sealant-310ml?q=Pyro+mate+fire+silicone

 

[Mattja]

Ahh fair enough, I was thinking specifically about some old metal fuse boxes I'm come across which are non-combustible, but have notable gaps in them which may let in air to fuel a fire.

Guess I'll use it to bring up the IP ratings, but not make any suggestion that it's going to stop/delay a fire just incase.

 

[bigspark17]

Im with midwest, sealing the hole would only fullfill the ip4x or ip2x depending on surface! If the db is not non combustabile i would suggest a c3. (Domestically)

 

[Andy78]

Ahh fair enough, I was thinking specifically about some old metal fuse boxes I'm come across which are non-combustible, but have notable gaps in them which may let in air to fuel a fire.

Guess I'll use it to bring up the IP ratings, but not make any suggestion that it's going to stop/delay a fire just incase.

What sort of gaps and where ? If they are circular knockouts, use metal bungs and locknuts. If another shape, a piece of metal plate bolted over will suffice. If the gaps are part of the design of the unit then just leave it. Obviously you have had reason to be in these boards so make sure to look for signs of thermal damage and ensure all connections are properly made and tight, same as you would normally do.

 

[Andy78]

Im with midwest, sealing the hole would only fullfill the ip4x or ip2x depending on surface! If the db is not non combustabile i would suggest a c3. (Domestically)

The advice is that a C3 is appropriate where the CU is in an escape route or under a wooden stair with no fire protection. No code otherwise.

 

[Mattja]

@andy the sort of gaps: Some unused knockouts that've been knocked out and left (think I'll use the bungs and locknuts like you suggest there), but mostly gaps where the plates forming the box don't quite meet up - one I've got in mind that looks like someone mistook it for a golf ball! Fair bit of gap between plates that've buckled a bit, but everything's holding together inside it and the guy doesn't want to get it replaced. Spotted some fire-retardant silicone while browsing for other bits and that's where this thread started!

 

[Andy78]

@andy the sort of gaps: Some unused knockouts that've been knocked out and left (think I'll use the bungs and locknuts like you suggest there), but mostly gaps where the plates forming the box don't quite meet up - one I've got in mind that looks like someone mistook it for a golf ball! Fair bit of gap between plates that've buckled a bit, but everything's holding together inside it and the guy doesn't want to get it replaced. Spotted some fire-retardant silicone while browsing for other bits and that's where this thread started!

If the gaps are from damage through impact that has caused deformation of the casing, then a bit of gunk squidged into it may not be suitable as a permanent repair.