German gas pipe grounds

[Open Neutral]

A friend in Wiesbaden related that he had an issue with an arcing panelboard ground. He'd also been having symptoms that screamed "open neutral" to me.

I freaked because it was a ground to the gas main feeding his house, and had been arcing under the clamp.

The POCO disclaimed responsibility and he paid a electrician to come out & investigate (EU 365 for afterhours callout). He arrived and in turn called the POCO who then did show up. They tightened the clamp but I remain concerned. The only reason I could see for such arcing was if that cable/clamp/pipe was actively carrying neutral current.

But I admit to knowing little of German wiring. I know they have 3-phase in far more residences than we do, and would assume that's 3hot+neutral.

Anyone familiar with their standards?

 

[jaggedben]

Not familiar with the grounding and bonding rules but my impression is most homes are 2-wire 230V L-N services off a wye system. Possibly some have 2 or 3 phase from the wye system but I'm kinda doubtful they have split phase like we do here. I could be wrong.

Interesting video of wiring methods. Not like we do here.

 

[hbiss]

Hmmm, I see they do specify distances from the ends and along the conduit run for supports. Also, box fill. But that's about it. Certainly wouldn't pass inspection here. I felt like saying get out of my way and start bending EMT and install a real panel!

Doesn't answer the OP's original question though of how to handle the service ground to the "panel".

-Hal

 

[Open Neutral]

Attached is a low-quality screen grab from a video he sent.
He was told this is an older box; better quality than the contemporary ones.
(My guess is it's a 3-phase disconnect with only one used.)

Per:
https://www.graphicproducts.com/articles/wire-color-coding/
it's blue hot, brown neutral, and yellow/green "PE" ground.

But none of this explains why there is current flowing down the PE/ground. It should be in the neutral.

I'd be screaming "Open Neutral" but both an electrician and the POCO were on-site; neither seemed concerned. What do they know that I don't?

 

[Jraef]

I have worked for a couple of German companies and although I never did any residential wiring, Germans are amazingly consistent if nothing else. They have very detailed “Planning Manuals” for everything and in my first job with them I was required to read and comprehend them cover to cover (18 full 3” binders) during the first 3 months of my employment (even though that had little to no relationship to US systems). That was now some 40+ years ago so I may have a few details wrong, but here goes…

In most areas of the world that do not conform to North American standards, they use IEC standards. Within IEC there are several “earthing systems”, all of them based on a “Star” (wye) 3 phase distribution system, but whether they bring all 3 phases into the home is irrelevant. The earthing systems are all the same and are called either TT, TN-C, TN-C-S or, sometimes, TN-S. The differences all have to do with how the Neutral and the “PE” (Protected Earth) are connected or separated. Different countries use different systems, so someone who, for example, knows what is done in Italy does not necessarily know what is done in Germany.

It’s too complicated to go into all of them, but Germany mostly uses the TN-C-S system, but some older smaller services still use TN-C and rural customers where there are only a few connections to a transformer might use TT. In TT the user is the only place where the PE and N are bonded because the utility N earthing would be considered unreliable (by their standards). Their TN-C and TN-C-S system, PE and N share the same conductor from the utility (called the PEN conductor) but with the TN-C-S they are split in the house and are kept separate everywhere else from that point on, so very similar to our system in that regard. In both cases however the service PEN is bonded either to the building foundation, or to their equivalent of a ground rod. So in any given neighborhood, every house is essentially aiding in bonding the PE and N (hence they’re considering the TT to be less reliable).

Then in each house there is another “earth bar” or “Potentialausgleichsschiene” (typical German mouthful word) which ALSO connects other systems to earth throughout the home, such as communications systems, any antennae, water pipes AND GAS PIPES. So they are not USING the gas pipe as their equivalent of a “grounding electrode”, they are BONDING it to the grounding electrode. If it was sparking from a loose connection, that was most likely gas line static trying to get to the grounding electrode, not the other way around.

 

[Open Neutral]

Thanks for some facts midst my muddle.
What bothers me is the issues he reported that sounded like an open neutral.

I will relay what you've taught me to him.

 

[Jraef]

Well he might have had an open neutral, but that would be separate from the gas pipe issue.

 

[Open Neutral]

True....

 

[Open Neutral]

I've been pondering if a bad neutral at House A would alter anything at House B such that it would explain the current via the gas line....

 

[retirede]

I've been pondering if a bad neutral at House A would alter anything at House B such that it would explain the current via the gas line....

In an open neutral condition, anything that’s bonded in more than one spot has the potential to be a substitute path for neutral current. If the gas pipe is bonded at both houses and is a conductive path between the two (no insulating union), it could be conducting neutral current.