Earthing bar from MET on TNS

michaellyonslo · Jan 12, 2023

Has anyone seen one of these please ? I propose a little earthing tape to identify it. I am upgrading the system and will put in place a new MET and signage. It looks like it could handle high amps on a fault. Should it therefore be deemed a pass on 3.5 of schedule of inspection ? Ps : backboard has been changed since photo by DNO

[ElectriciansForums.net] Earthing bar from MET on TNS

snowhead · Jan 12, 2023

There's no need to label it.

It's obvious what it is.
It's the property of the DNO.
If the DNO have changed the backboard and refitted the terminal block as per photo then they must be happy with it as it is.

mainline · Jan 12, 2023

michaellyonslo said:
Has anyone seen one of these please ? I propose a little earthing tape to identify it. I am upgrading the system and will put in place a new MET and signage. It looks like it could handle high amps on a fault. Should it therefore be deemed a pass on 3.5 of schedule of inspection ? Ps : backboard has been changed since photo by DNO

I would treat it as a MET outside an enclosure and as such needs to be labelled

mainline · Jan 12, 2023

snowhead said:
There's no need to label it.

It's obvious what it is.
It's the property of the DNO.
If the DNO have changed the backboard and refitted the terminal block as per photo then they must be happy with it as it is.

Main Earth Terminal (MET) outside of an enclosure/switchgear – Any Earthing terminal outside of an enclosure, such as the connection from a TNS cable sheath. Wherever the MET can be accessed without having to open an enclosure, a ‘SAFETY ELECTRICAL CONNECTION’ label needs to be displayed

timhoward · Jan 12, 2023

michaellyonslo said:
It looks like it could handle high amps on a fault. Should it therefore be deemed a pass on 3.5 of schedule of inspection ?

If it really concerns you then work out the prospective fault current, find out the disconnection time for the relevant fuse, and bung them in the adiabatic equation to find the cross sectional area of copper required.

Lucien Nunes · Jan 12, 2023

It looks like it could handle high amps on a fault.

It looks like a normal copper P-clamp screwed, and then additionally soldered, onto the lead. As such it will be a superb connection capable of anything required of it. I am not a fan of spurious labels or labels that state the obvious, but I do label external METs and earth connections especially if they look more 'mechanical' than electrical, as in this case where the main connection is a flat piece of metal rather than a cable.

michaellyonslo · Jan 12, 2023

Thanks all. Yes a P clamp ! Maybe pre second world war ! Good spot as i won't have to do any algebra on slide rules ! Thanks all on the labelling responses. No green yellow tape required as advised. Just fishing a bit on that and appreciate the clear advice. Attached photo FYI of what DNO left on isolator install and backboard replacement. I have just noticed the MET was left dangling. The guy muttered something on replacing the board and now i know why perhaps. Rather than make the disconnection notice levitate in air i will find some board in a skip to give it and the MET a proper home!

brianmoooore · Jan 12, 2023

If that MET was screwed to a board originally, and is now floating in space, I'd be registering a complaint and tell them to come back and finish the job properly.

michaellyonslo · Jan 13, 2023

brianmoooore said:
If that MET was screwed to a board originally, and is now floating in space, I'd be registering a complaint and tell them to come back and finish the job properly.

Thanks. I had to double check myself from my original photo posted on here at top of the thread that it was screwed on. There is a central screw. I have met the operative twice now and he is a good guy and his work quick and solid (usually). He gave me gratis a good length of 25mm l and n flexi tails on out first meeting for the consumer side of an isolator. I will sort this one and slap his wrist if we meet again. Show him photos !