Hi guys. To those in countries with TNC-S. What are your requirements regarding installation of earth rods for domestic installs?

[LastManOnline]

Hi Guys. Firstly, am glad to join the group. Secondly I am very curious to hear from those who have TNC-S as their electrical supply I have 2 questions (1) Are you required to install an earth rod (stake or mesh) on the homeowners property? and (2) what are your regulations regarding its resistance? Many thanks in advance.

 

[LastManOnline]

Agreed. The solutions have to be realistic. This issue was, nt caused overnight and certainly wo t be solve overnight. I think first step needs, to be an industry wide recoqnition of the issue and then a realistic balanced approach to solving it. For instance, as previously mentioned, underground TNCS supplies are much less at risk. I would suggest beginning with looking at measures first in areas with overhead supplies which tend to pose the greatest risks.

Agreed. The solutions have to be realistic. This issue was, nt caused overnight and certainly wo t be solve overnight. I think first step needs, to be an industry wide recoqnition of the issue and then a realistic balanced approach to solving it. For instance, as previously mentioned, underground TNCS supplies are much less at risk. I would suggest beginning with looking at measures first in areas with overhead supplies which tend to pose the greatest risks.

When an electrical fault takes place inside the home protective measures are in place to ensure its cleared within seconds via mcbs and rcds. Bonding ensures that the homeowner is protected for the duration of the fault.


Is, nt it ironic that when a fault takes place outside the home (DSO, s neutral breaks) there currently are no measures in place to clear the fault. All outside metalwork (garden lights, heatpumps, electric gates etc) is now live. Co summers mcb, s and rcd, s are rendered ineffective.

Obviously we have no control over DSO, s network. But at the consumers end, what if we were to install a mains contactor? DSO, s neutral breaks, Contactor automatically decouples the live as well. Danger to home removed. DSO, s repairs fault and contactor automatically kicks in again. I don't propose this as a permanent sution, rather a stopgap. What do you think?

 

[LastManOnline]

Yes I agree the cost would be expensive, but we should start somewhere, maybe with new builds for starters.
The dangers of a broken PEN can be catastrophic.

Hi Dave. Am agreed about the "catastrophic" consequences and the "need to start somewhere". What do you think about the proposed "stopgap" solution I replied to "dave sparks" with?

 

[davesparks]

Hi Dave. Am agreed about the "catastrophic" consequences and the "need to start somewhere". What do you think about the proposed "stopgap" solution I replied to "dave sparks" with?

What is your stopgap soloution?

Bearing in mind anything intended as a stopgap will almost certainly become permanent

 

[LastManOnline]

What is your stopgap soloution?

Bearing in mind anything intended as a stopgap will almost certainly become permanent

Think I might have made a "dogs dinner" of a previous post. Did you get to read my post from Sat morning about the mains contactor which would drop out when DSO, s neutral breaks? That was a, proposed stopgap solution.
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What is your stopgap soloution?

Bearing in mind anything intended as a stopgap will almost certainly become permanent

Think I might have made a "dogs dinner" of a previous post. Did you get to read my post from Sat morning about the mains contactor which would drop out when DSO, s neutral breaks? That was a, proposed stopgap solution.

Just realised that the post I intended for you on Sat morning I inadvertently sent to myself?. Anyway just scroll back and it's there

 

[davesparks]

Think I might have made a "dogs dinner" of a previous post. Did you get to read my post from Sat morning about the mains contactor which would drop out when DSO, s neutral breaks? That was a, proposed stopgap solution

How do you see that being rolled out?

Contactors can, and do fail, this would likely cause more problems than it solves.
If the contactor is energised 24/7 until a PEN fault occurs then it will likely burn out the coil, or be stuck closed, long before a fault occurs, plus it will be a lot of wasted energy holding all those contactors closed.
If the contactor energised on the failure of the PEN with the load connected through N/C contacts there is still the risk of sticking due to years of not moving, plus the issue of getting a reliable circuit to operate it without an incoming neutral.

You can't have a soloution which fails more commonly than the fault it is supposed to protect against occurs.

Maybe thinking along those lines something could be done on the DNO's installation to signal the substation to trip out an affected distributing main when a PEN fault occurs. But again the risk of failure may be greater than the risk of the fault being protected against.

 

[LastManOnline]

How do you see that being rolled out?

Contactors can, and do fail, this would likely cause more problems than it solves.
If the contactor is energised 24/7 until a PEN fault occurs then it will likely burn out the coil, or be stuck closed, long before a fault occurs, plus it will be a lot of wasted energy holding all those contactors closed.
If the contactor energised on the failure of the PEN with the load connected through N/C contacts there is still the risk of sticking due to years of not moving, plus the issue of getting a reliable circuit to operate it without an incoming neutral.

You can't have a soloution which fails more commonly than the fault it is supposed to protect against occurs.

Maybe thinking along those lines something could be done on the DNO's installation to signal the substation to trip out an affected distributing main when a PEN fault occurs. But again the risk of failure may be greater than the risk of the fault being protected against.

We are here in Ireland heading towards a 100 % TNC-S supply system. So for us it's a question of when, not if there will be an increase in PEN faults.
It would not be realistic at this point to expect the DSO to do a u-turn and change supply system so the only real option is some protective measure.whether its your suggestion of the DSO taking some measure to trip out a, faulty line or my suggestion to trip out a contactor in the home or some other variant (or some hybrid), is all up for debate and discussion. But I think the key thing is to get a discussion going and that has happened and hopefully that will bear some fruit. Its clear that on this forum that sparks on the ground are aware and concerned and I see that as really encouraging