ELECSA Certification Scheme Regulations Clarification (ELECSA Assesment)

[Richard Burns]

The earthing conductor from cut out to MET is only required to be 16mm² when using the selection table and it is stated in the regulations that this is likely to provide oversized conductors, therefore using the adiabatic equation (in this case subject to the bonding requirements as well) is a better and more comprehensive design.
There is no decrease applicable from MET to CU because of the size of the switch fuse as it is the same size (probably) as the cut out fuse and in both cases would be overidden by the bonding requirements.

 

[westward10]

The earthing conductor from cut out to MET is only required to be 16mm² when using the selection table and it is stated in the regulations that this is likely to provide oversized conductors, therefore using the adiabatic equation (in this case subject to the bonding requirements as well) is a better and more comprehensive design.
There is no decrease applicable from MET to CU because of the size of the switch fuse as it is the same size (probably) as the cut out fuse and in both cases would be overidden by the bonding requirements.

Not disagreeing with you Richard at all just that the OP would need to be confident if the assessor queried why it wasn't 16.0, some of them only see things in black and white. Either way it needs changing as it is undersized to support the new bonding.

 

[Nickj]

I'm happy to put 10mm and will justify if they ask with the information you've provided above and a little more research.

The question I would be stuck answering is if he notices I've run 10mm to the MET but nit from there to the cut out. As yy say above richard this is probably not acceptable for the bonding.

Would he accept me saying I can't legally touch beyond the MET. Could he not retort then you should have paid DNO to upgrade it?

What I am doing us providing a significant improvement in safety (no rcd currently). I'd be leaving the installation in a much better state than currently. Is it really fair for them to expect people to pay silly amounts of money (dno) to improve overall safety!

 

[westward10]

The earth from the head definitely needs changing, why change bonding if the earth at source is 6.0.

 

[Nickj]

Ok, so I'll contact DNO Monday and ask how much to upgrade earth at cut out and arrange for it to be done.

Assessment is 8th November so plenty of time for them to turn up.

I'll proceed with changing the broken switches and pendant in bathroom and once DNO have done their part i'll proceed with the board change - RCBOs most likely for 4 circuits (as not going to put a ring in kitchen to save on costs). 4 rcbos and a board will cost same as fully populated split load board anyway.

I'll re-use old tails and make observations on the cert about the cooker isolator and limited sockets in kitchen.

All that sound like a pass in theory? I'm much less stressed now. This forum is incredibly useful

 

[Richard Burns]

The situation is usually that the DNO will provide an earth cable/ connection from the cut out to the MET.
The size of this cable is up to the DNO to ascertain if it is suitable.
The DNO are responsible for the maintenance of the earth connection from the incoming supply.
Looking at the arrangement you have this was probably originally from the cut out to the earth bar of the CU.
For some reason the earth has been cut and joined in a terminal block in the meter cabinet.
This could move the position of the MET from the CU to the terminal block, which is what has been suggested here by providing an earth block and labelling in the meter cabinet.
The DNO would therefore be responsible for the cable to the earth block, which is why I said it is worth asking them, as they should not charge you for this.
However since they provided the PME and did not provide a 10mm² earth at the time, why not?
Will they be keen to expend their money on a change they did not deem necessary at the time?
Effectively that piece of cable is outside the remit of BS7671 and is under the ESQCR instead.
I do not think, but do not know that, the ESQCR would permit this size of cable but it does seem odd they left it at that size.

Overall it sounds like you have a plan in place and are making every effort to comply and have justification for your choices, which is what the assessor will be looking for.
Roll on 8th November!

 

[Nickj]

Thank you to everyone who has helped.

I will speak to the DNO on Monday and push for a free upgrade. After which I'll certainly know more as to thir position on the matter.

Thanks

 

[mhar]

For Western Power it is a condition of pme supply that the earthing conductor is 16mm and the bonding 10mm. However not something that they rigourously enforce!
Perhaps a call to the dno advising that the fuse needs resealing and that they have not removed the knockout over the pme earthing terminal in the cutout will provide a no cost solution to your concerns. If they are already in attendance to re-seal it is barely any extra effort to remove the knockout

 

[Midwest]

Seems you have a plan in place, so I'll try not to muddy the waters now, but I have a couple of points.

MK do a populated 12 way CU, http://www.screwfix.com/p/mk-sentry-100a-12-way-main-switch-metal-consumer-unit-6-x-rcbos/8318p for £132. Don't think Wylex sell an RCBO populated one? Check the MK RCBO's have 'Honeywell' on the front, or you might have some defective devices.

When you ring WP for them to come and have a look, they might give you a 5 week lead time, unless you say their main earth looks a bit dodgy, and they might make it an emergency and come the same day So factor that with you assessment date, don't try rush things.

Do some preliminary work; find the route of your existing tails, see if you have any slack cable, for when you do install your new CU. I suspect they will appear from the cavity into the ceiling void, and then run down to the existing CU. As someone suggested a while back, do some test on your existing install to make sure you haven't any nightmares waiting to spoil the party.

 

[Nickj]

Mhar, I really don't mind putting a 16mm earth so long as I can leave the existing tails?

Midwest thank you for the link to that board. I like the look of mk and so I'll go with that one. It'll leave 2 spare rcbos as well for the same price as buying BG separately.

My assessment is 6 weeks Tuesday -sounds far off but I'm sure it'll creep up on me. Especially as I have a 2 week holiday between. If the dno want 5 weeks to sort it then it fits in fine. I'll get all preliminary work completed and issue MWCs for the light changes and switch changes (not absolutely necessary but some more paperwork to show assessor).

I just hope that WP don't charge for changing their inadequate earthing arrangement!

 

[Midwest]

I'll get all preliminary work completed and issue MWCs for the light changes and switch changes (not absolutely necessary but some more paperwork to show assessor).

Don't make more work for yourself. Start the EIC (for the CU), include your other works in that. Show your assessor the EIC. When you've passed your assessment, and got your shiny badge, bin the paper EIC and use the Elecsa on-line forms to complete a new EIC. Then you can notify the BC through Elecsa when finalising your Elecsa EIC. Save a few trees

 

[Nickj]

Thought i'd leave an update regarding this. I phoned WPD this morning and told them their earth was inadequate, being 6mm on PME.

I was ready to fight to get a free upgrade however there was no need. The guy on phone said that's too small I'll get someone out to you today to assess.

40 Minutes later a chap turned up who looked at it and said definitely needed upgrading and he'll have it scheduled for tomorrow or Wednesday.

Result

 

[Midwest]

Cool, keeps your assessment on track

 

[westward10]

Thought i'd leave an update regarding this. I phoned WPD this morning and told them their earth was inadequate, being 6mm on PME.

I was ready to fight to get a free upgrade however there was no need. The guy on phone said that's too small I'll get someone out to you today to assess.

40 Minutes later a chap turned up who looked at it and said definitely needed upgrading and he'll have it scheduled for tomorrow or Wednesday.

Result

Good start hope the rest is plain sailing also.