CU, head and meter enclosures fire resistance

[EFLImpudence]

Stairs ? one fo the CU's will be near to a staircase ... and part of the esacape route.

Stairs are made of non-fire-rated wood - and possibly carpet.
Domestic premises do not have official escape routes. Everywhere is a potential actual escape route.

FRA - so he does not have any jurisdiction over the electrical installation ?

I wouldn't think so.
Does he work for the council? Is it an HMO?

In a domestic setup - in what circumstances would a 1.5 or 2.5 copper cable be likely to glow red, I am sure it happens,

If too much current flows through it.
The only way that can happen in a usual installation would be if someone swapped a cable for a smaller one through ignorance.
Loose connections could cause very localised heating.

hence why they changed CU's from plastic to metal,

No that is not the reason.
It was a suggestion from the London Fire Brigade because they said plastic CUs were the cause of some fires.

Loose connections might have been the real reason but it lead to a very strange regulation that all CUs must be made of, or enclosed in, non-combustible material. That's it; no other measures have been introduced.
Steel was mentioned in this regulation as such a material and instantly there was nothing else available.

 

[AndyPRK]

Wires also need to be clipped with metal like clips where a hazzard would exist if they dropped in a fire. I think that’s an 18th Ed request. Common sense indicates On new cables installed

 

[JohnW2]

Wires also need to be clipped with metal like clips where a hazzard would exist if they dropped in a fire. I think that’s an 18th Ed request. Common sense indicates On new cables installed

Prior to 18th, there was such a regulation, but it applied only to 'escape routes' (whatever they may be in standard domestic premises), but 18th extended the requirement to the entire installation.

Kind Regards, John

 

[Astra99]

It is unfortunate, but fire brigades in general, not only in London, if they cannot be certain of the cause of a fire, say it was as a result of "an electrical fault". True, electricity cannot be seen or smelled. Only its effects can be determined. Is this *really* a reason to "demonise" electricity, and by vociferous lobbying, get legislation passed which merely complicates matters for the majority?

 

[JohnW2]

It is unfortunate, but fire brigades in general, not only in London, if they cannot be certain of the cause of a fire, say it was as a result of "an electrical fault". True, electricity cannot be seen or smelled. Only its effects can be determined. Is this *really* a reason to "demonise" electricity, and by vociferous lobbying, get legislation passed which merely complicates matters for the majority?

Unfortunately, that seems to be very true.

Even more unfortunately, it appears that the IET+BSI (or, at least JPEL/64) appear (in relation to 'non-combustible' CUs) not to have been strong enough to resist LFB's lobbying about which I suspect they shared the view of most of us that the change in regulations was completely unnecessary. Rumour has it that they 'threatened' JPEL/64 (I presume with engineering legislation, that would 'trump' BS7671), but I have no idea if that was the case.

Quite apart from anything else, the LFB did not seem to grasp the fact that IF (and this seems far from certain) fires originating in CUs were common enough to warrant a nationwide change in regulations, it was not because CU enclosures were 'spontaneously combusting' but, rather, because something had gone wrong within the CU, resulting in a fire starting within. Under such circumstances, if it is deemed that action is necessary, it should surely be somehow directed at the underlying cause of the fire (an electrical problem within the CU), not the enclosure?

If it became known that some electrical domestic appliance was commonly initiating house fires, the appropriate action would surely be directed at rectifying the problem in the appliance, not requiring that it be installed within a 'fireproof cabinet'?!!

Kind Regards, John

 

[bernardgreen]

I too consider that the decision to have "non flammable" cases for consumer units is based of flawed data.

With an arc burning inside the metal consumer unit the case can get hot enough to ignite material outside the consumer unit. How often is a consumer unit hidden behind coats or other flammable items ?

It is unfortunate, but fire brigades in general, not only in London, if they cannot be certain of the cause of a fire, say it was as a result of "an electrical fault".

I had a friend who was a Fire Investigation Officer, he knew that "electrical faults" were very often the cause of a fire.

A large percentage of domestic fires are started by an electrical fault. A few of these fires are due to faults / failures / errors in the installation and many are due to faulty electrical appliances.

If it became known that some electrical domestic appliance was commonly initiating house fires, the appropriate action would surely be directed at rectifying the problem in the appliance

I suspect that John's comment was directed at appliances inside the consumer units. The majority of heat generating faults in consumer units were caused by loose terminals.

Fire brigades have tried to make the general public aware of the dangers that arise when electrical appliances are either mis-used or are too cheap to be safe in operation.

 

[AndyPRK]

If people can’t be trusted the tighten terminals, design good screws , or make quality mcbs that don’t catch fire I think a slow change to metal with sealed cable holes wasn’t a bad idea.

But now if every rental place in the country has to have one than that is s step too far!

 

[davelx]

Prior to 18th, there was such a regulation, but it applied only to 'escape routes' (whatever they may be in standard domestic premises), but 18th extended the requirement to the entire installation.

Kind Regards, John

Does anyone know where to buy metal cable clips for 10mm² T&E?

I can only find up to 6.

 

[JohnW2]

If it became known that some electrical domestic appliance was commonly initiating house fires, the appropriate action would surely be directed at rectifying the problem in the appliance, not requiring that it be installed within a 'fireproof cabinet'?!!

I suspect that John's comment was directed at appliances inside the consumer units.

You suspect incorrectly

I was making a totally general (and, I would have thought, common sense) point. For example, if it became known that a certain make of electric toothbrush had a habit of spontaneously bursting into flames, the obvious thing to do would be to address the problem with the toothbrushes (probably involving a 'recall') - NOT by advising/requiring people to store them in fire-resistant enclosures when not in use.

The majority of heat generating faults in consumer units were caused by loose terminals.

Indeed - and IF it's a sufficiently common problem to warrant/require some 'action', then it surely is that 'loose terminal' issue that should be addressed, rather than allowing the fires to carry on starting but requiring that the enclosur surrounding them will not also burn (albeit, as I've been saying, there are no requirements for 'fire containment').

Much as I have (probably irrational) 'intuitive uneasiness' about spring-loaded terminals, maybe a move to them within CUs (rather than screwed terminals) would be a far more rational approach than requiring the enclosure to be 'non-combustible' ??

Kind Regards, John

 

[JohnW2]

Does anyone know where to buy metal cable clips for 10mm² T&E? I can only find up to 6.

Certainly not easy to find. You could always use buckle clips.

Kind Regards, John

 

[EFLImpudence]

Of course you don't have to use metal clips along the whole run. Probably just every couple of metres (or more) would stop it falling in a fire.

Out of interest, is this domestic? Where would a 10mm² cable be installed where it could fall in a fire and be a hazard to the firemen?

 

[JohnW2]

Of course you don't have to use metal clips along the whole run. Probably just every couple of metres (or more) would stop it falling in a fire.

Indeed, and a don't see why they would have to be purpose-made metal cable clips. Anything metal that would prevent such falling (e.g. metal plumbing saddle clips), not necessarily normally even in contact with the cable, would presumably satisfy the requirement?

Out of interest, is this domestic? Where would a 10mm² cable be installed where it could fall in a fire and be a hazard to the firemen?

Shower feed on/above a bathroom ceiling?

Kind Regards, John

 

[flameport]

metal cable clips for 10mm² T&E?

https://www.linianclip.co.uk/product/linian-te-clip/

 

[EFLImpudence]

Shower feed on/above a bathroom ceiling?

I suppose you are right -

although I was not thinking above a ceiling which had to fall first would be covered especially as previously it only applied to escape routes.

Any way, the aesthetics of the clips above a ceiling is not important. A couple of nails would do.

 

[JohnW2]

I suppose you are right - although I was not thinking above a ceiling which had to fall first would be covered especially as previously it only applied to escape routes.

Indeed. Mind you, I've seen shower cables in surface mini-trunking across a ceiling, so the ceiling doesn't necessarily have to 'fall first', anyway/

Any way, the aesthetics of the clips above a ceiling is not important. A couple of nails would do.

Quite so - and, as I said, it doesn't necessarily have to be as crude as 'a couple if nails'. There are plenty of plumbing and general hardware hings that would do the job ... and, as I also said, if one actually feels the need to use some 'electrical' product, there are always metal buckle clips.

Kind Regards, John