- #1
Calvadosser
- 39
- 0
I'm living in France and have just replaced my "chauffe eau" - a 200 litre hot water tank with built in 2.4kW electrical heater and thermostat.
The instructions say that it should be installed with an electrically insulating joint where the hot water outlet pipe is attached. I bought a pair of joints (they are only sold as pairs - 20 euros per pair) and their instructions said that one should be installed on the cold inlet and one on the hot outlet. They are sold as prolonging the life of the tank.
I have dutifully installed these joints. They are made of metal but with a tough plastic washer preventing the two ends coming into contact.
I assumed that the function of the "dielectric joints" as they are called is to prevent the steel tank being corroded by electrolysis resulting from being in contact with the copper water pipes.
However, there is something I don't understand. The copper hot and cold water pipes are bonded to the ground connection of the house's electrical supply, in accordance with French electrical norms. Likewise, the steel case of the hot water tank is connected to the ground connection of the house's electrical supply.
Here is what is puzzling me. I'd be grateful if anyone could point out what I am missing. I can't see what is the point of having the electrically isolating joints if the pipes they are meant to be isolating are connected, via the grounding cables, to the case of the tank anyway.
What am I missing?
Martin
The instructions say that it should be installed with an electrically insulating joint where the hot water outlet pipe is attached. I bought a pair of joints (they are only sold as pairs - 20 euros per pair) and their instructions said that one should be installed on the cold inlet and one on the hot outlet. They are sold as prolonging the life of the tank.
I have dutifully installed these joints. They are made of metal but with a tough plastic washer preventing the two ends coming into contact.
I assumed that the function of the "dielectric joints" as they are called is to prevent the steel tank being corroded by electrolysis resulting from being in contact with the copper water pipes.
However, there is something I don't understand. The copper hot and cold water pipes are bonded to the ground connection of the house's electrical supply, in accordance with French electrical norms. Likewise, the steel case of the hot water tank is connected to the ground connection of the house's electrical supply.
Here is what is puzzling me. I'd be grateful if anyone could point out what I am missing. I can't see what is the point of having the electrically isolating joints if the pipes they are meant to be isolating are connected, via the grounding cables, to the case of the tank anyway.
What am I missing?
Martin