UK TNCS CPC not used

[Stuart A]

Hi All,
As mentioned, I’ve got what looks like a TNCS system but CPC is coming via an earth rod???? Not tested TNCS system yet to see if earthing is acceptable

 

[westward10]

How can we help?

 

[mhar]

Is this a property on it's own with it's own transformer?

 

[timhoward]

There is nothing to stop anyone adding earth rods to a TNCS system. Amendment 2 mentions this.
The real questions are probably:
-is it TNCS system?
-does the earth rod have a specialist purpose that needs to be understood?
Feel free to stick some photos up.
(Obviously, measuring what you think is the external loop impedance from the supplier, as well as the L-N loop impedance would help.)

 

[brianmoooore]

There can be reasons for setting up a TT system, even if a TNC-S earthing terminal is available. Usually because of the difficulty of bonding items.

 

[pc1966]

They could have got there by many different means: it could have been TT and DNO now converted to TN-C-S, or it could still be TT if there was reason(s) to want to avoid the supplier's earth (for example, it feeds extensive outdoor metalwork, areas where PME is prohibited, etc).

As @timhoward says there is no harm, and often a small advantage, in adding rods to the supply earth, so if it simply is that situation then nothing really needs changing.

 

[R-fur]

What type of installation is it? In certain circumstances such as temporary supplies to building sites the DNO can put in a TNCS supply but with hold the earth connection so that the site has to TT it.

 

[MDJ]

Hi All,
As mentioned, I’ve got what looks like a TNCS system but CPC is coming via an earth rod???? Not tested TNCS system yet to see if earthing is acceptable

CPC or Main Earth?

 

[7029 dave]

CPC or Main Earth?

Good to see you Mike

 

[MDJ]

Good to see you Mike

and you Dave