Earth query

[jay_t]

been to look at a board change today, it's an old board with rewireable fuses, tn-s system.

There is a clamp around the sheath of the supply cable with a 4mm earth cable running up to the earth block in the current board, i assume this cable needs upgrading (tails are 16mm, so i assume the earth needs to be 16mm too even though Ze is 0.11)

Also there is no sign of bonding at all!! I did a continuity test from the gas pipe to the closest earth point (an adjacent socket) just out of interest and got a reading of around 60 ohms (i assume that confirms no bonding and the figure i'm getting is the path through the ground)

what do you think? does it sound as though the bonding is not there? it certainly wasn't visible from todays quick poke around.

I've been asked to put in a price for a new board and have mentioned the bonding to them what would you quote for new board and installation of bonding to gas and water?

I've done a few board changes before, but not domestic, and have all been pme and relatively straightforward

 

[Andy™]

you will need DNO to upgrade that bit of 4mm, but since Ze is OK, they will just leave it or give you a nice large bill for it.

best option would be to put a earth block next to head, take 4mm to that, then your shiny new 16 from there to DB.

Gas and water earth will have to be done aswell

 

[SLIPSHOD & SLAPDASH]

you will need DNO to upgrade that bit of 4mm, but since Ze is OK, they will just leave it or give you a nice large bill for it.best option would be to put a earth block next to head, take 4mm to that, then your shiny new 16 from there to DB.

Gas and water earth will have to be done aswell

Spot on reply old bean. Guiness Drink

 

[SLIPSHOD & SLAPDASH]

Since the tails are 16mm, only a 10mm earth is needed.

 

[fastham]

Sorry,

Should the tails now be 25mm and earth 16mm?

 

[batty]

Sorry,Should the tails now be 25mm and earth 16mm?

Not if its a 60amp main fuse which a lot are. If its got a 4mm earth probably is 60 amp. You must be a newby welcome to the forum.

Batty

 

[Apache]

Not if its a 60amp main fuse which a lot are. If its got a 4mm earth probably is 60 amp. You must be a newby welcome to the forum.Batty

he's been with us since 4th March!

 

[batty]

he's been with us since 4th March!

Not a big poster though.

batty

That ain't the right word but you know what I mean.

 

[batty]

he's been with us since 4th March!

You are starting to confuse things I was talking about Fastham not Jayt

Batty

?:|

 

[Apache]

You are starting to confuse things I was talking about Fastham not JaytBatty

?:|

please accept my most sincere apologies - thought you mean OP!

It's been a long day

 

[fastham]

Hi guys,

Yes new to your site,

round here we come across a lot of new cut outs at 80/100 amp but still with 4mm earth.

just a warning that was all.

didnt mean to cause confusion

regards

Fastham

 

[Doc Hudson]

Hi guys,Yes new to your site,

round here we come across a lot of new cut outs at 80/100 amp but still with 4mm earth.

just a warning that was all.

didnt mean to cause confusion

regards

Fastham

Welcome to the forum Fastham, I don't think you caused any confusion, Apache and Batty are very able to confuse themselves I believe.

Doc H.

 

[seajayess]

Since the tails are 16mm, only a 10mm earth is needed.

Table 4.1 OSG 16mm tails require 16mm earthing conductor

Bonding conductor can be 10mm CJS

 

[binky]

Table 4.1 OSG 16mm tails require 16mm earthing conductor Bonding conductor can be 10mm CJS

OSG and the like tend to also show TT systems as requiring 16mm earth as well, so don't take that as gospel - check the regs.

 

[SLIPSHOD & SLAPDASH]

Table 4.1 OSG 16mm tails require 16mm earthing conductor Bonding conductor can be 10mm CJS

Thanks for pointing that out. I cant remember the last time i did not use 25mm tails & 16mm main earth, so had forgot this changed in the 17th edition.

Can someone point me to a recent thread where a poster claimed if all circuits are RCD protected only a very small main earth is needed.

 

[Apache]

Thanks for pointing that out. I cant remember the last time i did not use 25mm tails & 16mm main earth, so had forgot this changed in the 17th edition.Can someone point me to a recent thread where a poster claimed if all circuits are RCD protected only a very small main earth is needed.

http://www.talk.electricianforum.co.uk/showthread.php?t=3028&page=2

#27

 

[SLIPSHOD & SLAPDASH]

Ta, so nicky did not reply then.

 

[SPECIAL LOCATION]

Thanks for pointing that out. I cant remember the last time i did not use 25mm tails & 16mm main earth, so had forgot this changed in the 17th edition.Can someone point me to a recent thread where a poster claimed if all circuits are RCD protected only a very small main earth is needed.

cant remember the thread..

but it was n. tessla as far as I remember?

 

[SPECIAL LOCATION]

******!

should have read the second page befor posting!!!

just ignore me!!! :_| :_|

 

[SPECIAL LOCATION]

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