UK Should I get the main earth changed by the DNO?

Snailspark · Sep 15, 2019

I have been asked to upgrade a fuse board, however, when I did an initial visual inspection, I noticed the main earth from the DNO is unsheathed (TN-S), it’s strands that are clearly ancient!
I haven’t yet carried out any tests. Should I get the DNO to change the earth? Will they actually bother changing it? A new smart meter has recently been fitted and the tails were upgraded - should they not have replaced the earth then?
This picture shows the MET - the other cable is main bonding.
Any thoughts?

[ElectriciansForums.net] Should I get the main earth changed by the DNO?

buzzlightyear · Sep 15, 2019

Cosidering it the main earth from the dno which is nowt do with you .
And all test are good for Ze then i would get some green and yellow. Tape on the main earths to show any body cuting it off and a sign earths connection do not remove .
[automerge]1568504892[/automerge]
You also said a smarta## meter has been fitted is their a islolator near the main cut out ,other wise the tooth fairy needs to pull the main cut out .

Snailspark · Sep 15, 2019

buzzlightyear said:
Cosidering it the main earth from the dno which is nowt do with you .
And all test are good for Ze then i would get some green and yellow. Tape on the main earths to show any body cuting it off and a sign earths connection do not remove .
[automerge]1568504892[/automerge]
You also said a smarta## meter has been fitted is their a islolator near the main cut out ,other wise the tooth fairy needs to pull the main cut out .

There has been an isolator fitted yes so no need to touch their stuff...

Lucien Nunes · Sep 15, 2019

This is perfectly normal, it's a bare cable soldered to the service cable lead when that was installed. The CSA is usually smaller than you would choose today but in practice invariably meets (and well exceeds) the minimum required to satisfy the adiabatic, in which case it's fine. The leccy doesn't care whether it's green & yellow. In some countries bare main earths are standard practice today, they cannot be mistaken for anything else and any damage is easily visible.

braineebird · Sep 15, 2019

Snailspark said:
I have been asked to upgrade a fuse board, however, when I did an initial visual inspection, I noticed the main earth from the DNO is unsheathed (TN-S), it’s strands that are clearly ancient!
I haven’t yet carried out any tests. Should I get the DNO to change the earth? Will they actually bother changing it? A new smart meter has recently been fitted and the tails were upgraded - should they not have replaced the earth then?
This picture shows the MET - the other cable is main bonding.
Any thoughts?View attachment 52157

Do a quick ze test. If it's a good earth I'd sleeve it and use it. If not then get the dno involved

telectrix · Sep 15, 2019

send your apprentice to stores for some green/yellow striped paint.

davesparks · Sep 15, 2019

Calculate the size of earthing conductor required and check the size against that.

Don't just go by the Ze, you could have a good Ze on an undersized conductor.

Midwest · Sep 15, 2019

I must be the only one, that thinks that’s a mess. I’d contact the DNO and ask them to have a butchers, for flips sack!

Cid · Sep 15, 2019

If the Ze is good then dno won't be interested at all and neither should you.

Deleted member 105166 · Sep 15, 2019

You could ferrule the two multiwire terminations at the MET (526.9.1), I imagine you'd need to use the uninsulated variety to get sufficient length so as to maintain two terminal screws per termination, as an insulated ferrule would be too short and restricted by its insulation.

telectrix · Sep 15, 2019

TonyMitchell said:
You could ferrule the two multiwire terminations at the MET (526.9.1), I imagine you'd need to use the uninsulated variety to get sufficient length so as to maintain two terminal screws per termination, as an insulated ferrule would be too short and restricted by its insulation.

similar thoughts. could just be tidied up a bit. no need for ferrules though as it's 7 strand, just give it a bit of a twist.

Snailspark · Sep 15, 2019

Lucien Nunes said:
This is perfectly normal, it's a bare cable soldered to the service cable lead when that was installed. The CSA is usually smaller than you would choose today but in practice invariably meets (and well exceeds) the minimum required to satisfy the adiabatic, in which case it's fine. The leccy doesn't care whether it's green & yellow. In some countries bare main earths are standard practice today, they cannot be mistaken for anything else and any damage is easily visible.

If it all checks out ok - I will change the earth from the MET to my new fuse board to a proper one anyway..

telectrix · Sep 15, 2019

Snailspark said:
If it all checks out ok - I will change the earth from the MET to my new fuse board to a proper one anyway..

good move. the DNO provided earth will outlast me and probably you as well. sometimes the old school solutions are best. ( now where's my wind-up Megger?).

Percyprod · Sep 17, 2019

The service cable needs terminating, there should be a cover over the cable end at the bottom of the cut out. In effect the cable is single insulated. DNO would upgrade main earth at same time.

davesparks · Sep 17, 2019

Percyprod said:
The service cable needs terminating, there should be a cover over the cable end at the bottom of the cut out. In effect the cable is single insulated. DNO would upgrade main earth at same time.

The service cable is terminated and appears to have a heat shrink breakout boot fitted so the cable is in effect not single insulated.

UK Should I get the main earth changed by the DNO?

Snailspark

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buzzlightyear

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Snailspark

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Lucien Nunes

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braineebird

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telectrix

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davesparks

Midwest

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Cid

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Deleted member 105166

telectrix

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Snailspark

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telectrix

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Percyprod

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davesparks

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