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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.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.
I said “They should be treated” I didn't say “They are fire barriers”.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.
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.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.
. What constitutes a ‘non-combustible enclosure’?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.
It's purpose is not to contain a fire it is not a fire barrier. This is a common misconception.. 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.
But it isn't a fire barrier and is the partition a fire compartment boundary. Do you want a spade.It will be more of a fire barrier being metal than it would being made of wood, like that partition.
Regardless of the soundless/ strength of the argument I'm afraid some people argue just for the sake of it.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.
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.
But it isn't a fire barrier and is the partition a fire compartment boundary. Do you want a spade.
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)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.
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.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.
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.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.
Yes, you're correct if fire got into that partition it would be an issue.If it breeches a fire barrier then it is an issue. Define the parameters of a massive hole.
No it wouldn't be as there should be cavity barriers. The size of entry shouldn't be relevant as there will always be passage around the cables regardless of size.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.
No it wouldn't be as there should be cavity barriers. The size of entry shouldn't be relevant as there will always be passage around the cables regardless of size.
No reference is made regarding the rear.I could be wrong, and will happily stand corrected, but doesn't BS7671 make reference to holes in a domestic DB solely with regard to finger access in front, bottom or sides and holes larger than 1mm on top, with no reference made about rear?
The intent of Regulation 421.1.201 is considered to be, as far as is reasonably practicable, to contain any fire within the enclosure or cabinet and to minimise the escape of flames.I might be wrong, but when 421.1.201 first came out in the BYB, it was about removing the source of fuel for a fire, and nothing to do with containment of a fire.
Has this recently changed?
At no point does that Reguation infer to containing a fire.The intent of Regulation 421.1.201 is considered to be, as far as is reasonably practicable, to contain any fire within the enclosure or cabinet and to minimise the escape of flames.
It is important for the installer to seal all openings into the enclosure or cabinet for cables, conduits, trunking or ducting that remain after the installation of cables - see Figure 6. The intent of the sealing is to ensure that, as far as is reasonably practicable, any fire is contained within the enclosure or cabinet and the escape of flames to the surroundings of the cabinet or enclosure or into conduits trunking or ducting is minimised, as intended by Regulation 421.1.201.
Good workmanship and proper materials must be used, and account must be taken of the manufacturer’s relevant instructions if any.
At no point does that Reguation infer to containing a fire.
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