Earthing related questions

Modern waterworks nowadays uses lots of plastic tubing. So dont think that you will get a reliable earth contact that way. However, connecting anything metallic(heating, concrete skeleton metal, any metal in the bathroom, your (metal)watertubes, etc , to a reliable grounding rod , is fine. Just dont rely on the water service as a provider for ground. Also check at the entry point of the wiring entering your house, in our country (Netherlands) there is a reliable ground connection supplied by the electricity company.

Water supply generally uses metal pipe.. which is in the ground deep and makes for a good conductor, since it is coming in contact with a lot of ground.. The water main is just the main pipe that enters your home in some secure place where it's protected from cold weather to prevent freezing.. Being underground x number of feet, protects it from this problem..

If for some reason you lose the noodle from the pole and you have a ground problem with one of your appliances, You can have issues.!

The important point is right in the beginning of the article

Take a look at

and especially about the TN-C-S picture. In addition for the three phases L1, L2 and L3, there is also a combined Protective Earth/Neutral (PEN) wire from the transformer to the house. At the main distribution panel (or whatever you call it in different countries), the PEN is split into Protective Earth (PE) and Neutral (N) wires, which are kept separate inside the house.

In normal situations only the N conductor will carry some current but no current will flow in the PE conductor and all PE terminals in the house will be at the same potential (the potential of the PEN to PE/N split point). An isolation fault in a load device will drive a very large current into the PE conductor and then into the PEN conductor and finally blow the fuse in the corresponding live line.

Now assuming that every load device is working OK, but the loads on the phases are unequal, so some current is flowing from the house to the transformer through the PEN wire. Assuming the PEN wire is broken, the potential of all the in house PE and N conductors will float to some potential between the phases, depending of the size of the loads. In a single phase system, the PE and N conductors will float to the full line voltage. If there are truly grounded objects, such as water/gass pipes and someone touches it and the case of an equipment is floating, up to the full mains voltage would be across the person.

To avoid this, a separate grounding electrode is used at each house.

Notice that in the TN-C-S picture, the N star point of the transformer is connected to a grounding electrode at the transformer (as well as to the PEN line to the consumer).

When the PEN line between the transformer and consumer is broken, but both the transformer as well as the consumer earthing electrodes are intact, a current will flow through the earth to the transformer neutral point, thus the PE and N wires inside the house do not float freely at high and dangerous levels, but will remain in safe levels for humans (but not necessary for equipment).

Connecting the PEN to PE/N split point to the water system serves two purposes, as long as metallic pipes are used, the pipes will function as additional ground electrodes but it also functions as equipotential bonding

In practice, the grounding resistance can be quite high (several ohms) in a dry sandy environment, the potential can still float to dangerous levels.

By connecting all the in house PE and N wires, the incoming PEN wire, the water, gas, central heating pipes as well as antenna frame earth as well as the actual grounding electrode into a common bar, everything within the house will float at similar potentials, thus there is not a serious risk of touching the water pipe and an earthed device, even when both the PEN wire and the grounding electrode are broken or the grounding resistance is high.