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The Future of Fuse boards...?

Discuss The Future of Fuse boards...? in the UK Electrical Forum area at ElectriciansForums.net

It seems this debate has been played over and over on this forum before.

 
It seems this debate has been played over and over on this forum before.


Yet none of it seems to have influenced the consensus view among authors of The Wiring Regulations.

The thread you have linked was started by someone asking advice on how to drill holes in metal enclosures.
 
The problem is that the IET are a self appointed organisation that have published a paper called it the "IET Regulations" and it is not a statutory instrument and therefore not regulatory, a BS is advisory only.
 
The debate is over whether to leave an oversized hole in the rear of a CU that goes into a wooden partition.
Really, I thought it was about 'as far as is reasonably practicable, to contain any fire within the enclosure or cabinet and to minimise the escape of flames' which, if you accept that argument, means you need to do something the moveable flap on the front of a CU.

As most manufacturers seem to leave this 'unlocked' and un-sealed, it does really seem to make that argument flawed, does it not?

I recall linking that video of Elex @ Harrogate 2015, but seems IET insist on you being a member to view it now, scallywags.

However, this ESF piece, calls itself 'Consumer Unit Myths'. I'm not sure of its date;


It suggests the use of special glands etc, is a myth, which is demonstrated with the Hager hot wire test.
 
Really, I thought it was about 'as far as is reasonably practicable, to contain any fire within the enclosure or cabinet and to minimise the escape of flames' which, if you accept that argument, means you need to do something the moveable flap on the front of a CU.

As most manufacturers seem to leave this 'unlocked' and un-sealed, it does really seem to make that argument flawed, does it not?
Most new consumer unit have the door needed to be held up and there is a big difference between flames coming out of the front being dampened by the metal door than them going up between a wooden partition, especially if the consumer unit is a double stack one and the fire is on the lower bus bar.

I recall linking that video of Elex @ Harrogate 2015, but seems IET insist on you being a member to view it now, scallywags.

However, this ESF piece, calls itself 'Consumer Unit Myths'. I'm not sure of its date;


It suggests the use of special glands etc, is a myth, which is demonstrated with the Hager hot wire test.
Nobody said you had to use special glands, but it does say :

Is it necessary to use cable glands made from metal or intumescent sealing material for cable entries?

Good working practices such as minimising the size of a cable entry.

In any case, the requirements of regulation group 416.2 for barriers or enclosures must be met and manufacturers’ instructions, if any, should be taken into consideration.

I would also take into consideration sec 527.

The logic behind this is that such items should be of equivalent non-combustible construction in order for the intended requirement to be effective in terms of minimising the spread of fire originating from such equipment.
 
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Most new consumer unit have the door needed to be held up and there is a big difference between flames coming out of the front being dampened by the metal door than them going up between a wooden partition, especially if the consumer unit is a double stack one and the fire is on the lower bus bar.


Nobody said you had to use special glands, but it does say :

Is it necessary to use cable glands made from metal or intumescent sealing material for cable entries?

Good working practices such as minimising the size of a cable entry.

In any case, the requirements of regulation group 416.2 for barriers or enclosures must be met and manufacturers’ instructions, if any, should be taken into consideration.

I would also take into consideration sec 527.

The logic behind this is that such items should be of equivalent non-combustible construction in order for the intended requirement to be effective in terms of minimising the spread of fire originating from such equipment.
The video shows a Hager cu, without any flames coming out the plastic glands, plastic trunking entries and for that matter the flappy cu door.

But nor does it show them coming out of the plastic cu, it just melts and drops burning debris everywhere.

I don’t get your first point in your second bit?

Do you not accept, that intumescent glands, barriers etc etc, are not required?
 
Hands across the table and all that, but it does 🙂
The second bit was copied from your link, I should have taken it out, it also had a no on the end.

"Is it necessary to use cable glands made from metal or intumescent sealing material for cable entries? No"

So I'm getting a bit lost, are you not agreeing with what you quoted ?
 
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So I'm getting a bit lost
You're not the only one.
I'm not really interested as to what the IET, BS7671, or any on site guide has to say on the subject. I'm an engineer, and know that if a smouldering substance is placed inside a fireproof, but not airtight box, and that box has an opening into a vertically upwards open void, then the heat from the smouldering will cause air to flow into void, which, in turn, is likely to cause the smouldering substance to ignite, even if it is nominally self extinguishing, which will increase the airflow into the void, carrying heat and flame with it.
 
The second bit was copied from your link, I should have taken it out, it also had a no on the end.

"Is it necessary to use cable glands made from metal or intumescent sealing material for cable entries? No"

So I'm getting a bit lost, are you not agreeing with what you quoted ?
You‘ve lost me, but I think we’ve discussed this enough now.
 
You're quoting from an interview with someone who helped write BS7671 and not a consensus among the many people involved.

Since one individual espoused this view in 2015, there have been a number of subsequent editions of wiring regulations in which it could have been included. That it hasn't been included might be an indication of others not being in agreement. No matter, it seems odd that such clarification (if that's what we're taking it to be) has been omitted from successive editions - if indeed the IET's position was ever such.
I came across this one from 2019
 
The penetration of plasterboard and the like and its return to original state, when installing cables, has always been on my mind when carrying out an install. To the extent, I came to fitting intumescent collars around extract fans installed in plasterboard ceilings, and I only ever fitted fire resistant downlights (& noise for that fact), regardless, all trying to observe to 527.2.

I don't see it applies to surface mounted CU's, unless the surface its installed on, is breached. If thats what your suggesting?
 
EICR today.... mouse came straight in the back.

in other news apparently 1mm tastes the nicest
 

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Did you repremand him / her / whatever, for carrying out an act that could be extemely dangerous to themselves and worse, could lead to C.U's having to have rodent traps built in.
I think hes still in there dead so didnt waste my breath, theres fluff in the middle. I put the lid back on after showing the home owner, all devices are coated in mouse ---- too so ive gone with that board being an operational limitation/fkin biohazard ☣️ scheduled for replacement and worry about it then, and i will be sealing the back up thoroughly
 

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