ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades Earth fuse?

It looks to me as though these are indeed test links to allow the earth conductors to be opened for testing. I notice that one cable has a piece of blue tape on it. It could just be there by chance, or maybe it indicates the earth cable which is running to the neutral to ground the supply system?

I assume the "3 x 380V + N" designation is a Continental way of saying it's a 220/380V wye system.

Ah Mystery solved, they undoubtedly look like test links.

Thanks for the clarification -- I thought they looked so much thinner than the cables that they could well be fuses. I often think what would happen to them if a serious fault occurred and one of them went phut! so tend to keep a bit of distance.

In any case, I still wonder if they would not be best inside the secure transformer room, instead of out in the open like they are. If any troublemaker thought they would borrow a spanner and an extension lead from one of the workshops, they could enliven the entire building's earth points, no?

On every floor, in the labs, there are large metal sinks, about 2m X 1m, which are not bonded so far as one is able to see. This seems unusual to me, and I wonder if it is part of this strange TN-NET designation. I've never seen it anywhere else.

Beginning the Dutch word on the switch label is "hoofd" which is "head"; I suppose the usual English is "Master". "Schakelaar" is a switch. So, it turns off all the power in that area :-)

Thanks again for the info :-)

j

Whew!,
Thank God for that!.
I thought there must have been some nasty person going around, fusing people's Earth Conductors, while they were't looking.

 
Long shot — Top picture / 4 cables might be a test point for cathodic-protection monitoring.
Even longer shot — Lower picture could be a cathodic-protection rectifier. Both are used for large underground metal pipe, casings or tanks. Example.. www.vniigaz.com/english/production/pde/pde-tech.htm www.farwestcorrosion.com/fwst/dcpower/univers02.htm

One thing does have to be said about them wire clamps.
Considering that they are clamping 10mm earthing wires, they look a little on the light side.
And also, are they made of steel?.
Any earth busbar or clamp is made of Brass
here.

Hmmm. TN net simply means the neutral is actually a PEN, that means it may serve as a PE conductor. Usually this is split up into TN-C-S at the service entrance point, that means running a separate PE conductor. TN-C means just a PEN. If it's actually a TN-C system there _might_ be a reason for not bonding the sinks (corrosion issues?), otherwise there isn't.
Hoofdschakelar means main switch as you already said.
The 3x380V+N thing is weird and definitely not typically European. 220/380V is far more common. Maybe it has some special meaning.