Right old can of worms...

[GBDamo]

Those week I have mostly been fitting 20 x 10W flood lights on the sloping edge of a converted mill ceiling, nothing is straight, nothing level.

The supply to the lock up unit has just been supplied by the landlord along with a new DB with two circuits (lights & sockets)

This is the second lot of work I've done here, in both cases the landlord supplied the board and supply new.

The agreement with the landlord is any works we do is tested and our incomplete certificate is amended to the new supply certification to form a complete certificate.

This means that all source, bonding and submain OCPD details are unavailable to me, in fact they are inaccessible.

I have a ZDB of 0.31 ohms, which is fine for my needs, no 32A D types going in, just a 20A socket radial and 2 x C10s for lights.

However...I just couldn't help myself and got the wonder lead out.

The building is the old pillar and beam construction. Cast iron pillars with steel beams atop.

All the pillars gave something between 5 and 10 KOhms resistance to the incoming earth of the submain, the armour of a 10mm 4 core SWA.

There was a roller shutter door, somehow fixed to the steel beam, which gave 1KOm.

And finally, whilst there is no gas or water, there is a small section of copper pipe that transits the corner of the room @ 1KOhm,

So, all extraneous.

My observations will be noted on my part of the certificate but I doubt the LL will do anything about the bonding.

The mill is about 150m square, subdivided into many units of varying sizes.

Me bonding to the DB doesn't seem right as effectively all the steel is joined together and therefore all the steel will be bonded via this submain.

Am I right in thinking this should be bonded from the MET in something sized to the incoming line conductors.

 

[timhoward]

Without access to the supply and knowing the earthing system type you won't know whether it needs to be > 1/2 main earth or based on size of Neutral (for TNCS).
I agree it should be bonded to the MET. In any case you can't possibly know if the CPC of your sub-main is suitably sized to support the required bonding.

Whatever the arrangement I agree with your concern that you are installing stuff in an environment without the right bonding in place. Who ultimately signs this certificate?

 

[GBDamo]

Without access to the supply and knowing the earthing system type you won't know whether it needs to be > 1/2 main earth or based on size of Neutral (for TNCS).
I agree it should be bonded to the MET. In any case you can't possibly know if the CPC of your sub-main is suitably sized to support the required bonding.

Whatever the arrangement I agree with your concern that you are installing stuff in an environment without the right bonding in place. Who ultimately signs this certificate?

My worrry is that I will sign off the work I have done and the LLs cert will not materialise.

I will be making further enquiries with the landlord and their contract electricians.

 

[timhoward]

My worrry is that I will sign off the work I have done and the LLs cert will not materialise.

I will be making further enquiries with the landlord and their contract electricians.

Sounds like a good plan.
I’d be very wary of putting my name to something that I haven’t seen for myself.

I'd suggest one of two things....and I can't tell which way around the arrangement is supposed to work.

If you are being asked to sign a complete EIC, and you haven't seen the supply for yourself, then I'd imagine you'd have to write something in the "Extent of the installation covered by this certificate" section, maybe along lines of "final circuits from DB --- only , supply not accessible, supply details based on certificate number xxxx issued by yyyy on dd/mm/yyyy, copy attached." Or “supply details based on information provided by xxxxxx ltd.”

Or the contract electricians take responsibility for certification and include your results. You could then use a multi-part form and sign for design and construction but not overall testing. You could also sign the inspection schedule and schedule of test results for your work.
Your only putting your name to what you actually did then.