Another bloody TT question

[Millboy]

Hi chaps, This is part looking for advice, part moan. Bear with me..

Ive been asked to look at a rewire, no spec just what I think would be necessary (usually a mid range install, nothing fancy but no £1 sockets etc.) Now the install is 40-50 years old and is an overhead supply, as is common to the area the house is in. Looking at the earth coming in it is 2.5mm unsheathed, partially protected by rusty metal capping, and goes out the wall, disappearing under the concrete at the rear of the house, never to be seen again.

I included in my price a new rod, earth pit etc etc. Another electrician has been and told the client that the existing rod is fine and he's tested it blah blah blah (I tested it at 70 ohms). The point isn't that the reading is too high, IMO on a rewire everything needs to be put right ie. the rod needs to be accessible, connections protected etc. and that I'm not happy with the bare minimum size earthing conductor.

That's the moan over with now the question... The client says they want to go ahead with the rewire but keep the existing earth "if it satisfies the regs". Now I know there's a reg that says the connection should be accessible and protected from corrosion in the 17th, but if it was ok to bury them 40 years ago, then can it stay and not conform to the
current edition of regs?

 

[Amp David]

Well for starters if the earth is buried where it goes outside it has to be 16mm anyway. So the 2.5 is no good, so if this need replacing then by the time its been traced then the rod may aswel be replaced. Plus although 70 ohms is good, you could get better i reckon

 

[Millboy]

Thanks David but does it satisfy an earlier edition of the regs? And how are we supposed to know this? Does anyone swot up on the 14th edition?

 

[Octopus]

Seems a bit daft not to replace the spike and cable in a full rewire!

 

[Moses]

Thanks David but does it satisfy an earlier edition of the regs? And how are we supposed to know this? Does anyone swot up on the 14th edition?

Why should it comply with the previous regs?

Its a new install, so it should all comply with current regs.

 

[Silly Sausage]

Hi chaps, This is part looking for advice, part moan. Bear with me..

Ive been asked to look at a rewire, no spec just what I think would be necessary (usually a mid range install, nothing fancy but no £1 sockets etc.) Now the install is 40-50 years old and is an overhead supply, as is common to the area the house is in. Looking at the earth coming in it is 2.5mm unsheathed, partially protected by rusty metal capping, and goes out the wall, disappearing under the concrete at the rear of the house, never to be seen again.

I included in my price a new rod, earth pit etc etc. Another electrician has been and told the client that the existing rod is fine and he's tested it blah blah blah (I tested it at 70 ohms). The point isn't that the reading is too high, IMO on a rewire everything needs to be put right ie. the rod needs to be accessible, connections protected etc. and that I'm not happy with the bare minimum size earthing conductor.

That's the moan over with now the question... The client says they want to go ahead with the rewire but keep the existing earth "if it satisfies the regs". Now I know there's a reg that says the connection should be accessible and protected from corrosion in the 17th, but if it was ok to bury them 40 years ago, then can it stay and not conform to the
current edition of regs?

Another electrician, isn't, I think you are!

 

[telectrix]

the connection to the rod should be accessible anyway.

 

[Octopus]

the connection to the rod should be accessible anyway.

It is, under the concrete, all you need is a couple of hours and some hard labour. Many sparkies think that under carpets and floorboards is accessible too!! lol

 

[Sav]

Well for starters if the earth is buried where it goes outside it has to be 16mm anyway. So the 2.5 is no good, so if this need replacing then by the time its been traced then the rod may aswel be replaced. Plus although 70 ohms is good, you could get better i reckon

Hi David,
If the earth is unsheathed and un-protected, would may be 25mm have to be used ?

Sorry if I'm ahead of myself, TT systems always get me !!

Millboy, as we are currently using the 17th edition of the regs, I would go by them.
I dont know if anyone else agrees?

Sav

 

[Moses]

Hi David,
If the earth is unsheathed and un-protected, would may be 25mm have to be used ?

Sorry if I'm ahead of myself, TT systems always get me !!

Millboy, as we are currently using the 17th edition of the regs, I would go by them.
I dont know if anyone else agrees?

Sav

Sav, you write man,

Cable to the rod need to be 25mm all the way for proper good earth!

Anything less will give you not a strong earth.

 

[telectrix]

my understanding is that the Gn/Y insulation on the eartrhing conductor is sheathed so 16mm if not mechanically protected.

 

[telectrix]

Sav, you write man,

Cable to the rod need to be 25mm all the way for proper good earth!

Anything less will give you not a strong earth.

16mm, a strong earth you have, skywalker

 

[Guitarist]

Millboy, look at page 41 in the OSG for sizes.

 

[Deleted member 26818]

The minimum "Nominal cross-sectional area of earthing lead" was 6mm² in the 14th edition (for live conductors up to 16mm²).

 

[Millboy]

I'm firmly in the camp of upgrading it lol. I'll have a good look through the book tomorrow and if I can find a few regs to quote I think I can convince them to have it done. To be honest I'm annoyed that they've taken "super duper spark"s opinion over mine anyway.