This came up a while back why there was a requirement for mounting boxes and other equipment such as consumer units needing to be IP4x or xxD rated. There was a large fire a few years back in an old peoples home, the report was published last week, and one of the fatcors that may have contributed was a lack of grommets on the Distribution Board entry points, this cold have led to chaffing of the cable, or letting sparks out of the unsealed hole. Full report here, page 6:
Your link doesnt work but I immediately note the weasel words you quoted such as
"may have contributed"
"could have led to chafing" - Not sure how stationary items lying next to each other chafe but hey ho
"Letting sparks out of unsealed hole" - just might have some basis of assumption but not very likely if the board used circuit breakers, even with fuses its a one in a million shot
really just another bit of self serving guff from political sources
********************* Your link doesnt work but I immediately note the weasel words you quoted such as
"may have contributed"
"could have led to chafing" - Not sure how stationary items lying next to each other chafe but hey ho
"Letting sparks out of unsealed hole" - just might have some basis of assumption but not very likely if the board used circuit breakers, even with fuses its a one in a million shot
really just another bit of self serving guff from political sources
********************* Link works for me if you edit out the line wrap. See if
I thought CU had only to be IP2X. Or at least IP2X on the sides and bottom.
But the real cause was the lack of a grommet and the sharp metal edge on the CU.
Whilst there MAY have been some movement in the cables due to thermic cycling the damage was probably caused during installation.
What I want to know is how the fire brigade etc can decide that a missing grommet caused a fire that looked like this?
The fire investigation department put anything that they cannot be bothered to investigate properly down to "electrical fault".
When my girlfriends next door neighbours car caught, the fire report was "elecrical fire". However when another neighbour played back his CCTV two lads had poured petrol down the bonnet air vent and set fire to it.
Some years ago an empty house that I had rewired caught fire. Again the fire department said "electrical fault". When I pointed out that the house had had the electricity supply cut off several years earlier the insurance company asked the nextdoor neighbour why shy had phoned the police just before the fire. She replied, "well I had just watched 3 kids break into the house and I phoned the fire brigade after I watched them set fire to it"
They are not 'weasel words' you idiot, read the report. What the f*ck have I got to gain? It is FA to do with me, a query came up a few months back about why CU's have to be IP rated.
Read the report YTC. Cables get warm in use, so they expand, then contract, this can cause chaffing on the insulation over time.
But during testing, it was found to be a risk, so a report was published to bring this to the attention of anyone with an interest. I've seen MCBs give off a large flash. Fuses are worse as the molten metal can fly off.
What? They are giving probable causes for a fire, so that others can learn from the possible mistakes made on this installation, and hopefully make a note to not make the same mistakes in the future.
Well, yes. I suppose it could be possible that the grommet was there and had burnt away completely, though maybe they had more info than shown, to lead them to thewir conclusions.
Whilst this is true as stated, it's no reliable indication of cause. A fire near live conductors is likely to remove the insulation and then lead to this sort of damage, but it's not the cause of the fire.
This is not just any rubber grommet, its an intrinsically safe rubber grommet, specially supplied by M&S Electrical so that your whole house is spark free and smelling of freshly picked roses.
I really dont know what you have to gain apart from making yourself look foolish but is there some point in you parroting claptrap about a subject you evidently know nothing about? The only requirement of the regulations (BS7671 - 2008 416.2.2 for the initiated) is for the TOP surface of the enclosure to be IP4x or xxD with apertures intended to exclude particles of greater than 1mm diameter. This is to prevent crap such as swarf falling into the enclosure while air currents may pass for cooling purposes. The bottom and sides of the enclosure only need to be IP2x which is a very significantly larger aperture and will not stop sparks. The following is a reasonable description of IP2x and illustrates well the standard.
for IP2X
The test is made with a metallic British standard finger 12.5mm in diameter. Full penetration into the enclosure is not allowed, both joints of the finger may be bent through 90 degrees with respect to the axis of the finger but in one and the same direction only. The finger is pushed without undue force, maximum 10 Newtons, against any opening in the enclosure. If it enters it is placed in every possible position. A low voltage supply not less than 40v and not exceeding 50v is placed in series with a suitable test lamp, the test finger and the live parts within the enclosure, the protection is satisfactory if the lamp does not light. To comply to IP2X the test finger must have adequate clearance from hazardous parts.
for IPXXB Full penetration of the British Standard test finger to a maximum of
80mm, the test is the same as that stated in IP2X and the finger must not come into contact with hazardous parts to comply to this requirement
If the installation passes IPXXB then it also passes IP2X
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