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

[Miketwinny]

got a 16mm earthing conductor from main supply sheath goin in to the MET + an earth electrode(rod) next to the supply with a 10mm earthing conductor comin off it to the MET
Should I class it as a TT system for test results and mark the EIC as TN-S & TT :nonod:

 

[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