What size ground wire is needed for a 200 amp service panel in Canada ONT?
Minimum size grounding conductor for a 200 amp service entrance is #6 bare copper.
It depends on where the sub panel is situated. If the panel is under the same roof as the main distribution panel then no ground rods are needed on the sub panel. If the sub panel is in a different building then a ground rod might be needed. There has been an electrical code rule change on this subject. Check with your local electrical inspector before installation so that it is done correctly.
Answer for USA, Canada and countries running a 60 Hertz supply service. The ground wire is not bonded to the neutral wire in a sub panel because the sub panel is considered to be a branch circuit from the main panel. Only the main panel is grounded at the neutral. Any faults at the sub panel would return direct to the main panel through the ground wire in the cable feeding the sub panel. If…
On a 200 amp or any size service the ground wire is easily identified. Look in the distribution panel for the neutral bus bar. This is where the service neutral (white wire) is connected to the distribution panel. There you will see a bare copper wire connected to the same neutral bar. This is the ground wire that is connected to the ground rods out side of the house.