Screwfix 17th ed metal consumer units, compliant?

If you look hard enough you can find anything to suit any arguement. The IET and BEAMA are the only people we need to be listening to.

 

Well I think I'm just going to cut a load of 20mm holes out in the back and put grommets in and thread as many cables as I can through each.

as a side thought. Do the cables now have to be in trunking in a meter cupboard in a lounge. I can't get them up behind the skirting like the existing ones are so they're going in front. Non of the existing are covered. We never bothered because it's a meter cupboard

 

It is interesting that people have took it upon themselves to decide that a domestic CU must utilise fire protection measures on the basis that the words 'non-combustible' has been used in the Regulation. They have made a conscious link to fire simply because of the wording. Had the wording been simply that domestic CUs must be made of metal, I doubt that any of this paranoia would have escalated to the levels of madness that has been demonstrated by one and all.

In the Regulation there was an example cited that ferrous metal would be acceptable as a non-combustible material. Industrial distribution boards are made of metal and yet the paranoia generated by the domestic requirement has never troubled industrial electricians. I find this quite interesting.

I am convinced that the wording of the Regulation has caused all this and it just goes to show how powerful words can be.

The same psychology is present in the behaviour of electricians. Having made the erroneous link from non-combustible to fire protection they then concern themselves with measures that prevent fire when they don't need to. They imagine fire stopping cable entries; they worry about cutting large holes in the metal; they imagine lids must be kept shut to contain the flames; they worry over blanking plates being plastic; they condemn all previous plastic CUs as being fire hazards. The human psychology is given to making spurious links to unnecessary measures purely on the basis of a word.

Now if you can all comprehend this mental arithmetic and see exactly how my mind works to unravel the strange behaviour then I hope you will all see just how crazy things have got and how incredibly gullible people are to compounding misinformation and misunderstandings.

 

The psychology that generates erroneous actions works irrespective of who they are and what they represent. The simple fact is you and everyone else have made exactly the same mistake. BEAMA and the IET have people making the same errors. It is unstoppable because of people being who they are. It takes a lot more in depth thought to control subsequent human behaviour resulting from how a Regulation is worded. Get the requirement wording wrong and the result is what we have seen. Totally inappropriate response to a very simple instruction.

 

Psychology in action. Hahahaha

 

I'm going off iet guide videos and manufacturers videos, not my interpretation of a few words in a book. They say its meant to prevent fire getting out the enclosure, not be fire proof. If it were meant to be fire proof we'd not be allowed to have a ip4 gap or use grommets or bushes or standard trunking. A brass bush with a strip of trunking across to satisfy the IP rating does not seal around the 1.00mm cable and the bush. That's psychology in action

 

Same with the lids. If they didn't comply going down they'd have not made them that way

 

madhatter its pointless me saying any more. People have made their minds up and that's that.

 

I have to disagree. I think you have made some valid points for discussion.

The psychology that many electricians do as you have mentioned is correct. We can see this with earth bonding on combi boilers when an electricians loops earth cable to each pipe coming of the bottom of a combi boiler.
Of course it is not needed as the boiler itself is a class1 appliance and has the entire metal parts within the boiler already earthed. It is good to go the extra mile to do a better quality job but within reason.



As far as going the extra mile in using intumescent sealants or whatever on a consumer unit is a bit OTT. As the new amendment states, the purpose of a non combustible enclosure is so the enclosure does not contribute to the fire spreading and would effectively contain the small fire in the enclosure in the hope it will extinguish before it has a chance to ignite surrounding combustibles.

You are not trying to seal smoke in from escaping nor are you trying to give the consumer unit a fire rating time as to allow people to escape from a burning building.
The fire service in the UK think that by using a non combustible enclosure it will prevent the fire from spreading and in all fairness i agree with that as the case cant burn and wont let the fire get out of control.

Intumescent sealing is particularly for doors and glazing. It's purpose is to seal in the event of fire so that smoke and toxic fumes can not escape the seal for a give period of time. This provides time for people in hotels, flats, office buildings etc which have hallways and communals that people will need to use to get out. If these are filled with toxic smoke you don't stand a chance in getting out so intumescent seals are used to assist in stopping the smoke form leaking from a burning room into the escape routes whatever they maybe.

Now to apply that to a consumer unit, well it seems a bit silly don't you think. For years industry has had the Metal consumer unit installed. When an electrical fault happens the metal unit contains the fire well and does not burn down the factory unless there are flammable chemicals close by. Stupidity can not be cured sorry.
I mean who in their right mind would put a jerry can full of petrol in the cupboard with the consumer unit...

We could venture deep into the level of toxic fumes produced by each and every material found in the home but seriously well beyond the scope of this thread. The lesser the combustion materials found around a high risk source of ignition the better and safer it is.
Id say a consumer unit does qualify as a potential source of ignition and hence the word containment of that source once again.

 

One thing they do keep showing though is a tail gland. I assume because they usually enter from bellow and you need to ip maintain the entrance hole

 

But anyway. The wooden meter cupboard. Trunk in cables or just clip? They're just clipped at the moment. Or I could box them in. It's one of those things I've never thought about before

 

You can achieve that in many ways, by a gland or grommet or edge protection.

It is so that the metal sharp edges of the enclosure do not cut through the tails insulation and make contact with the metal case.
It is in fact to add protection against the incoming tails from making contact with the enclosure.
Every circuit that goes out to the dwelling is wired to a protection device, the incoming tails just have a 60Amp or 100Amp fuse attached to them(most common fuses). This is more important to use glands when using a TT system. One thing that is a concern is the ability of a consumer unit to become loose on the wall and the ability for the tails to become loose, maybe the supply company wants to change the meter. By these tails being disturbed without a grommet or gland in place, that movement could rub on the entry hole and cause the insulation become damaged and make contact with the case. It can also cause the tails in the main switch to wiggle loose

It is very important to make sure in every scenario that the live incoming tails have had every effort taken to avoid them coming into contact with the enclosure.

That is the real reason for adding a gland to the tails.

 

And to maintain the ip protection

 

Well if you are that way inclined of course it can be.
IP40DH0

 

Excellent - my inspector insisted that my boiler pipes had to be cross bonded. I whipped in a main just after the stop cock fed by mdpe) and did exactly what was done in the picture. I also ran a 10mm from met to gas cab,

 

Yes Gas and Water pipes need bonding but to bond all the pipes out the boiler like in the pic is not going to cause a problem but it really is not needed.

Why would anyone bond MDPE lol.
If the pipe coming in from outside is metal then it will need bonding but if it is plastic and all metal pipes are inside the house and there is no metal pipes going outside then it won't need bonding. It wont harm to bond them but it is not needed.
Bathroom bonding still applies regardless of the water supply coming in on MDPE pipe. Bathroom hot water pipes are bonded to cold water pipes which are then bonded to the earth of the light and then the earth of the shower if one exists.

If pipes are buried in a concrete floor and of that nature then yea bond them. Either way it does not cause any harm doing so. Better to have it and not need it that need it and not have it.

Does your stop cock connect to the mdpe inside the house or outside?
If the tap is outside and then comes in that would be why it would need bonding.

Did you measure the resistances?

http://electrical.theiet.org/wiring-matters/27/bonding.cfm?type=pdf

Also it seemed that many years ago earth bonding was a go wild habit, inspectors wanted to see more green/yellow wires than blue or brown.
What defines an inspectors competence, i wonder.

 

Hi Fire. The water main to my stop cock is blue mdpe (I ran this in when doing my extension) After the cock all piping is in ct - this means all pipes ch/hw/cw/feed to tank etc etc no plastic whatsoever, Thus I have a main bond just after the cock. From this runs the cross bonding to all boiler pipes and this includes prv piping and 22mm gas. From my met also runs a 10mm main bond to my gas cab (this was put in by me some time back) As said my inspector did insist on this setup, and as I have always cross bonded at this position anyway I was happy to do it..it doesn't really cost much to do

I measured and I know it was always under 0.05 at any position, which is all ok.

 

Well as you say, whatever the inspector wants lol.

I am a HAM operator so ground loops in my installations are a no no but then again what normal person installs lightning arrestors and RFI, EMI supressors in their installation and drives in multiple earth rods to ground a radio station with super low impedance.
All be it very few people erect massive antenna arrays.
I gave up years ago trying to explain the importance of a carefully designing earth bonding and earth circuits for HAM radio operation.

Inspectors, put some nightshade in their tea ... just kidding but seriously they leave much to be desired.

 

My bro's going to fire up his Cobra and burner soon Fire. He has got a silver eagle mike - just needs another antenna and stuff..got the swr gauge so wont blow the output trannys - big ol motorolas in the burner output stage.

 

Sweet, silver eagle mike, he likes the traditional vintage stuff then.
I like my old valve radios but do i use them? Rarely as they cost me way to much in electricity cost. You need a 40+amp circuit just to power that stuff lol.
What is the Cobra, 11 metre or 10 and 11 metre?