TN-S & TT on same installation what should I class it as?

[Miketwinny]

All sorted new clamps on Gas & Rod and new MET

 

[44ALLAN]

True, live and learn.What would you recommend grind rod down and fill hole or just connect to MET with new clamp and 10mm cable.

Gotta hold my hand up Mike and admit I missed that too until it was pointed out so your not alone lol.
Bloody easy this game innit:thinking:

 

[GLENNSPARK]

All sorted new clamps on Gas & Rod and new METView attachment 18088

Mike...can you secure those main bonding conductors (clip them) please...
dont just leave them flying like that...too easy for them to get caught and ragged off the clamps see...

 

[Miketwinny]

next job when I get the clips

 

[DPG]

Re: TN-S & TT on same installation what should I class it as?

What's the story with the copper pipe top-side of the earth clamp? Is that some sort of horrendous bending job? Daz

- - - Updated - - -

What's the story with the copper pipe top-side of the earth clamp? Is that some sort of horrendous bending job? Daz

 

[Miketwinny]

Re: TN-S & TT on same installation what should I class it as?

Gas feed to cooker through to other room

 

[GLENNSPARK]

Re: TN-S & TT on same installation what should I class it as?

Gas feed to cooker through to other room

it looks all leathered where its bent...

 

[mamba]

It is simply a TN-s system period as you have a suppliers earth as your primary earth. The Earth rod is purely that and is not and should not be translated as a TT system. The earth rod is there as a belt and braces job and to provide and give a better earth path only. The only issue you may have is a PFC as with the very low resitance to earth you will possibly get a very high Earth Fault current exceeding the Ka of your protective device/devices. Your short circuit fault current will be considerably lower. In Compex installation the better the earthing arrangement - and in design additional earth rods are by design placed in the installation for greater protection. Why remove it as its offering a good additional earth path - doing its job.

 

[Bobster]

I doubt he will have any higher than 3-4Ka maximum, even if he's near the Dno tx.

 

[mamba]

I doubt he will have any higher than 3-4Ka maximum, even if he's near the Dno tx.

Yep aggree as however PFC could be as high and should not 16Ka on a 230 supply as per OSG page 70 As said May be high so a measure to ensure devices meet capasity

 

[Bobster]

Considering the pefc being circa 1.4ka I doubt it's higher than 2ka.

Your right that it should be tested, and I'm sure the op has done.

 

[Engineer54]

It is simply a TN-s system period as you have a suppliers earth as your primary earth. The Earth rod is purely that and is not and should not be translated as a TT system. The earth rod is there as a belt and braces job and to provide and give a better earth path only. The only issue you may have is a PFC as with the very low resitance to earth you will possibly get a very high Earth Fault current exceeding the Ka of your protective device/devices. Your short circuit fault current will be considerably lower. In Compex installation the better the earthing arrangement - and in design additional earth rods are by design placed in the installation for greater protection. Why remove it as its offering a good additional earth path - doing its job.

I doubt very much, if that thin twig is going to offer any form of addition protection to this TN-S installation whatsoever!! lol!!

Higher earth fault current, exceeding KA of protective devices?? Only in your wildest of dreams!! lol!!

 

[DPG]

I'd be getting that gas pipe and cooker installation checked out. Pipe looks like it's been hammered to &!**@#. Daz

 

[somersetsparks]

Its just a TNS system with supplementary rod I imagine, not uncommon.
Don't disconnect the rod as suggested by someone earlier in thread though - As you when then have an Unbonded exteraneous conductiive part.
Leave it alone, I would possibly note the stake in the bonding section.

 

[Miketwinny]

PEFC 1.41Ka
PSCC 2.4Ka
Ze of earth rod 316 Ohms