The Future of Fuse boards...?

[Dustydazzler]

Looks nice

 

[mainline]

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

3rd Amendment Metal Consumer Units - best practice advice please - Electricians Forums; Electrical Advice

Afternoon all, I've been doing domestic electrics for about 4yrs now and although I've done a few circuit alterations on metal clad consumer units I'd say that 95% of my work has been with plastic ones. I'm totally comfortable with replacing a consumer unit and all that it...

www.electriciansforums.net

 

[nicebutdim]

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

3rd Amendment Metal Consumer Units - best practice advice please - Electricians Forums; Electrical Advice

Afternoon all, I've been doing domestic electrics for about 4yrs now and although I've done a few circuit alterations on metal clad consumer units I'd say that 95% of my work has been with plastic ones. I'm totally comfortable with replacing a consumer unit and all that it...

www.electriciansforums.net

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.

 

[mainline]

I am a member of the IET and totally disagree with it.

Totally disagree with the fact of there being an IET ?

 

[littlespark]

Anyone else think we’re going round in circles?

“You spin me right round, baby right round”

 

[Mike Johnson]

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.

 

[nicebutdim]

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.

Perhaps the wiring regulations are not statutory, but they most certainly are regulatory

 

[Mike Johnson]

Only if you are a member and subscribe to the IET as your regulatory body.

 

[Midwest]

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;

https://www.-----------------------...es/technical-e-news/consumer-unit-mythbuster/

It suggests the use of special glands etc, is a myth, which is demonstrated with the Hager hot wire test.

 

[mainline]

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;

https://www.-----------------------...es/technical-e-news/consumer-unit-mythbuster/

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.

 

[Midwest]

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?

 

[mainline]

The bit “Is it necessary to use cable glands made from metal or intumescent sealing material for cable entries?”
Should have had a “no” on the end

 

[Midwest]

The bit “Is it necessary to use cable glands made from metal or intumescent sealing material for cable entries?”
Should have had a “no” on the end

Hands across the table and all that, but it does

 

[mainline]

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 ?

 

[brianmoooore]

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.

 

[Midwest]

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.