TT Earth cable sizing

[chloebear]

Hi al,
Just need a bit of a refresh regarding the sizing of the earth cable for a domestic installation with an earth spike. I believe 10mm for the gas & water bonding, but seem to recall that the main earth cable can also be 10mm?

 

[Octopus]

On a TT system the earth cable to the spike can be 6mm, but I always fit 10mm as it makes sense when your equipotential bonding is 10mm

 

[Sickmick]

Main bonding hasn't got to be 10mm on a TT system.

 

[spark 68]

As others have said, it doesn't have to be 10mm, and can be 6mm, but as I usually carry 10mm for main bonding anyway, I usually use this, as it saves having to stock/carry another roll/size of cable

 

[malcolmsanford]

Main bonding hasn't got to be 10mm on a TT system.

Can you point this out in the regs please as my copy seems to have omitted this!!!

For a TT system you can have a 2.5mm main protective conductor if you so wish and the way to size is is done via reg 543.1.3.

 

[ackbarthestar]

I would size it according to pme supplies, not that it needs it at present.
Two reasons
1/ Possible upgrade at a future date to pme
2/ Mechanical protection of the the earthing conductor and from corrosion.

 

[Deleted member 26818]

TT main earth 2.5mm² minimum, if mechanicaly protected, 4mm² if not (Reg. No. 543.1.1).
If buried, 16mm² sheathed, 25mm² unsheathed (table 54.1).
Bonding 6mm² minimum (Reg. No. 544.1.1).

 

[spark 68]

Hi malcom,

Can you point this out in the regs please as my copy seems to have omitted this

544.1.1, and table 4.1 OSG, but not less than 6mm

too slow again

 

[malcolmsanford]

Hi malcom,



544.1.1, and table 4.1 OSG, but not less than 6mm





too slow again

But it is not 10mm as was posted, 10mm minimum is for TNC-S

 

[spark 68]

Originally Posted by Sickmick
Main bonding hasn't got to be 10mm on a TT system.

Can you point this out in the regs please as my copy seems to have omitted this!!!

For a TT system you can have a 2.5mm main protective conductor if you so wish and the way to size is is done via reg 543.1.3.

Not really sure what you are getting at Malcom ???

 

[malcolmsanford]

Ahhhhhhhhhhhhhhhhhhhhhhhhh Trip to spec savers for me

Sickmick I do apologize I missed the 't from you post, but it is an age thing

And spark 68 thanks for pointing that out, before I crashed into a heap.

:leaving:
so that's me leaving

 

[telectrix]

couple of large shots of JD might help, malc.