Ungrounded Main Electrical Panels

Older homes in Edmonton use or once used metal water supply pipes, made of copper, galvanized steel or even lead piping to bring water into the house from the city water main.  If they need to be replaced, these pipes will be replaced with plastic water lines.  (We are talking only about the pipe that carries the water into your house up to the water meter.)  The problem here is that older houses with metal water lines traditionally used the water line as a ground for the main electrical panel.  When a water line used for ground is replaced with plastic, a new ground connection, directly to the ground, will have to installed, or a potentially dangerous situation exists.

Loss of grounding through water line replacement is mainly a concern with older houses.  Newer houses no longer rely on water lines for grounding the electrical panel, and have dedicated ground rods or ground plates buried in the earth.  Proper earth grounding may also be an issue for mobile homes, ‘off the grid’ cabins with generators or solar panels and outbuildings such as detached garages that receive power through a branch circuit.

If you live in an older house where the water line has been replaced with plastic, you need to make sure that your main electrical panel is properly grounded.  An electrician or a qualified and licensed home inspector will be able to tell you if you have a properly grounded main panel if you do not know what to look for.

The picture below is an example of a ground connection for an electrical panel that is no longer a ground connection.  The bare copper wire goes into the main electrical panel and is fastened to the inside of the panel and the neutral wire.  The green wire is a telephone system ground wire.  Both used to be bonded to a probably galvanized incoming water line, since replaced with the green plastic water line that can be seen in the lowest part of the picture.  Neither the electrical panel or telephone system is properly grounded anymore.  A special CSA approved ground plate or ground rod will have to buried at least 600 mm deep in the soil and connected to the neutral bus in the main electrical panel to correct this situation. The existing ground wires will need to be bonded, that is, electrically connected to the metal box of the electrical panel using a ground screw inside the panel.

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