The Future of Fuse boards...?

[Dustydazzler]

Looks nice

 

[brianmoooore]

Used twin row (2 x 10W) MEM plastic boards for years on loads of domestic installations.

 

[mainline]

Looks nice

I really can't see the point of cutting a cable entry hole that size in the back board.

 

[Dustydazzler]

I really can't see the point of cutting a cable entry hole that size in the back board.

It is a pre punched knock out

 

[mainline]

It is a pre punched knock out

In the wooden partition.

 

[mattg4321]

I can’t see the point of removing the DIN rail!

 

[freddo]

In the wooden partition.

didn't you see the video? It's to prepare for all the future circuits for your battery banks and electric car charging points! (If you can afford it after spending all your money on the CU) Just feed the cable into the already made hole...

 

[mainline]

didn't you see the video? It's to prepare for all the future circuits for your battery banks and electric car charging points! (If you can afford it after spending all your money on the CU) Just feed the cable into the already made hole...

Except that they probably wouldn't come in from the back.

 

[Dave OCD]

In the wooden partition.

Well it's smaller than the steel knockout and makes it nice and easy to feed the cables into the back of the CU, so what's the point in making the cutout smaller and more fiddly ?

 

[freddo]

The large hole helps vent the flames into the wall void.

 

[mainline]

Well it's smaller than the steel knockout and makes it nice and easy to feed the cables into the back of the CU, so what's the point in making the cutout smaller and more fiddly ?

It's into a partition, nothing is going to be easy to get back entry into that CU.

 

[brianmoooore]

The large hole helps vent the flames into the wall void.

Exactly! The enclosure is not air tight, and heat inside will be fanned into flames by the chimney effect of the void. just like nominally non flammable insulation on the outside of high rise buildings.

 

[Dustydazzler]

Most sparks I see just mash a hole in the wall with their claw hammer big enough to put your head through...

 

[mainline]

Well it's smaller than the steel knockout and makes it nice and easy to feed the cables into the back of the CU, so what's the point in making the cutout smaller and more fiddly ?

Going with that logic, they may as well knock all of them out, that would make it a lot easier.

 

[Dave OCD]

Totally irrelevant. And there is nothing in the Regs about making a CU 'airtight' , if anything that's counter productive as we're told to install in such a way to minimise the build up of heat or words to that effect.

 

[westward10]

There shouldn't be a chimney effect as there should be cavity barriers for this purpose.

 

[mainline]

Totally irrelevant. And there is nothing in the Regs about making a CU 'airtight' , if anything that's counter productive as we're told to install in such a way to minimise the build up of heat or words to that effect.

As far as is reasonably practicable, to contain any fire within the enclosure or cabinet and to minimise the escape of flames.

 

[Dustydazzler]

Won't be long before everyone is filling a consumer unit with expanding foam

 

[Dave OCD]

Don't give anybody ideas ! Can you imagine trying to add a cable to that ?!

 

[littlespark]

Won't be long before everyone is filling a consumer unit with expanding foam

Intumescent foam, of course.

 

[Dustydazzler]

I can just imagine Delroys face when he turn up to do a Youtuber domestic board change this year only to find some sparky has completely filled it to the brim with builders foam...

NO WAY NO WAY A QUALIFIED ELECTRICIAN DONE THAT I CAN'T SEE IT

 

[brianmoooore]

There shouldn't be a chimney effect as there should be cavity barriers for this purpose.

Might have been before the sparky pulled them out the way to get his cables down.

 

[mainline]

Imagine telling a customer that they need to spend a load of money on a new metal consumer unit, telling them how much safer it is in a fire and then leaving a dirty great hole in their wall partition.

There is no argument for not sealing it up.

 

[Midwest]

Imagine telling a customer that they need to spend a load of money on a new metal consumer unit, telling them how much safer it is in a fire and then leaving a dirty great hole in their wall partition.

There is no argument for not sealing it up.

Here we go again

I tried using that naff grommet strip, including super gluing it, never stays it place, even when carefully inserting a larger cable. Hager bespoke grommet is the same. Manufacturers should come up with something more substantial.

 

[freddo]

We use a much deeper grommet strip (similar to this) than the silly short stuff the wholesalers stock.

 

[suffolkspark]

people C2 open backed wylex boards on a flammable wall if no paxolin sheet, but then wang a load of these knockouts out for 6 cables to come in

 

[mainline]

Totally irrelevant. And there is nothing in the Regs about making a CU 'airtight' , if anything that's counter productive as we're told to install in such a way to minimise the build up of heat or words to that effect.

I think that most people would know what Brian meant when saying “airtight”.

Also, I don't understand how you can disagree about leaving a dirty, great hole in a wall cavity.

Have a read of section 527.

 

[westward10]

I think that most people would know what Brian meant when saying “airtight”.

Also, I don't understand how you can disagree about leaving a dirty, great hole in a wall cavity.

Have a read of section 527.

Has the penetration breached a fire compartment because if not no further action is required.

 

[mainline]

Has the penetration breached a fire compartment because if not no further action is required.

The metal CU should be treated as a form of fire barrier/containment, that being the whole reason for having metal CUs in the first place.

Cutting a hole that size in a wooden partition and leaving it cannot be said to be the work of a decent electrician.

 

[littlespark]

Fill it with asbestos. Job’s a good ‘un

 

[westward10]

The metal CU should be treated as a form of fire barrier/containment, that being the whole reason for having metal CUs in the first place.

Cutting a hole that size in a wooden partition and leaving it cannot be said to be the work of a decent electrician.

No metal consumer units are not fire barriers because if they were then you would spend a considerable amount of money on them plus their Achilles heel would be cable entries and the protective devices. Metal consumer units are used because the enclosure does not readily combust, no more. You are misinformed.

 

[mainline]

No metal consumer units are not fire barriers because if they were then you would spend a considerable amount of money on them plus their Achilles heel would be cable entries and the protective devices. Metal consumer units are used because the enclosure does not readily combust, no more. You are misinformed.

I said “They should be treated” I didn't say “They are fire barriers”.

Common sense would tell you that cable entries that are sealed are going to act as a barrier.

 

[westward10]

I said “They should be treated” I didn't say “They are fire barriers”.

Common sense would tell you that cable entries that are sealed are going to act as a barrier.

You are giving incorrect information because just by stating this you believe it is a fire barrier. Common sense and fact are not necessarily the same because the size of entry is irrelevant and requires no sealing if it does not breech a fire compartment.

 

[mainline]

You are giving incorrect information because just by stating this you believe it is a fire barrier. Common sense and fact are not necessarily the same because the size of entry is irrelevant and requires no sealing if it does not breech a fire compartment.

. What constitutes a ‘non-combustible enclosure’?

A non-combustible enclosure includes base, cover, door and any components e.g. hinges, covers, screws and catches, necessary to maintain fire containment. See diagram 1. Blanks and devices are contained within the non-combustible enclosure.

3 How is account taken of cable entries into a ‘non-combustible enclosure’ with respect to
containment of internal fire and escape of flames?.

Good workmanship and proper materials must be applied by the installer. The cable installation entry method shall, as far as is reasonably practicable, maintain the fire containment of the enclosure. Account shall be taken of the manufacturers instructions, if any.

 

[suffolkspark]

Regs aside its just good practice and workmanship to not leave a hole big enough in the back for a fkin ferret to get in

 

[westward10]

. What constitutes a ‘non-combustible enclosure’?

A non-combustible enclosure includes base, cover, door and any components e.g. hinges, covers, screws and catches, necessary to maintain fire containment. See diagram 1. Blanks and devices are contained within the non-combustible enclosure.

3 How is account taken of cable entries into a ‘non-combustible enclosure’ with respect to
containment of internal fire and escape of flames?.

Good workmanship and proper materials must be applied by the installer. The cable installation entry method shall, as far as is reasonably practicable, maintain the fire containment of the enclosure. Account shall be taken of the manufacturers instructions, if any.

It's purpose is not to contain a fire it is not a fire barrier. This is a common misconception.

 

[Dustydazzler]

A metal board ( board made from non-combustible material ) does not form part of a buildings fire barrier

 

[mainline]

It's purpose is not to contain a fire it is not a fire barrier. This is a common misconception.

It will be more of a fire barrier being metal than it would being made of wood, like that partition.

 

[nicebutdim]

Out of interest. Do those who object to holes in the back of a DB insist upon installation of an interconnected smoke detection system, prior to upgrade of any domestic board?

Surely early detection of all types of fire would be of much greater importance than the short term containment of one unlikely source of fire.

 

[westward10]

It will be more of a fire barrier being metal than it would being made of wood, like that partition.

But it isn't a fire barrier and is the partition a fire compartment boundary. Do you want a spade.

 

[Dave OCD]

At no time have I advocated a huge cable entry hole, and assumptions are being made constantly. The vast majority of CUs that I replace are spaced off on small battens to facilitate all cables entering through the rear knockout. So in fact there is no hole going into a cavity at all. But when some people are convinced they're right and no one else knows what they're talking about then it's probably a waste of time posting at all.

 

[Dave OCD]

Out of interest. Do those who object to holes in the back of a DB insist upon installation of an interconnected smoke detection system, prior to upgrade of any domestic board?

Surely early detection of all types of fire would be of much greater importance than the short term containment of one unlikely source of fire.

Regardless of the soundless/ strength of the argument I'm afraid some people argue just for the sake of it.

 

[nicebutdim]

At no time have I advocated a huge cable entry hole, and assumptions are being made constantly. The vast majority of CUs that I replace are spaced off on small battens to facilitate all cables entering through the rear knockout. So in fact there is no hole going into a cavity at all. But when some people are convinced they're right and no one else knows what they're talking about then it's probably a waste of time posting at all.

To my mind this is the ideal method of installation, where practicable. Neat and provides for future repair or addition, without major upheaval.

 

[mainline]

But it isn't a fire barrier and is the partition a fire compartment boundary. Do you want a spade.

The issue is about leaving a massive hole into a wooden partition.

If some are happy to leave an installation like that, then good on them.

 

[ipf]

The metal CU should be treated as a form of fire barrier/containment, that being the whole reason for having metal CUs in the first place.

Cutting a hole that size in a wooden partition and leaving it cannot be said to be the work of a decent electrician.

No. The reason was because many of todays highly qualified dipsticks were incapable of installing non metal CU's correctly, causing an increasing danger of domestic CU fires. (in the London area, at least)

 

[nicebutdim]

The issue is about leaving a massive hole into a wooden partition.

If some are happy to leave an installation like that, then good on them.

The video that sparked this debate was set in a studio as a demonstration of how easily a particular DB could be installed. This was not a wooden partition in someone's home.

If one is to assume the intention was such, then one might wish to consider all possible alternatives - like that posted by @Dave OCD

 

[SparkySy]

I space them off the wall if going through the back makes life a lot easier on installation and future additions.

 

[westward10]

The issue is about leaving a massive hole into a wooden partition.

If some are happy to leave an installation like that, then good on them.

If it breeches a fire barrier then it is an issue. Define the parameters of a massive hole.

 

[ipf]

At no time have I advocated a huge cable entry hole, and assumptions are being made constantly. The vast majority of CUs that I replace are spaced off on small battens to facilitate all cables entering through the rear knockout. So in fact there is no hole going into a cavity at all. But when some people are convinced they're right and no one else knows what they're talking about then it's probably a waste of time posting at all.

That is much the preferred way.....and my way, mounted on ply wood with the timber hole filed smooth, smaller than the metal one, negating the need for grommet strip.

 

[mainline]

If it breeches a fire barrier then it is an issue. Define the parameters of a massive hole.

Yes, you're correct if fire got into that partition it would be an issue.

A hole that was cut much bigger than was needed.