Originally Posted By: jmyers
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To all concerned,
Maybe you already knew this but it is common in older homes I inspect to find multiwire circuits, meaning that two breakers share the same neutral. Typically you find this in 240 volt appliances but sometimes you find that the circuits are actually seperated into two entirely different circuits and are powered by two entirely different breakers which is allowed by the NEC (they do not have to be tied together in this case).
While according to the NEC this is ok but I always inform the client that if he intends to work on the panel to be certain the circuit is not multiwired which he will certainly find out very quickly if he disconnects the neutral wire without turning off both breakers.
It is fairly simple to find out if the panel has multiwired circuits present. Look around the knockouts for three wire with ground entering in the panel and count them. Now count the number of double pole breakers in the panel. If they match chances are you do not have any that are multiwired. If they don't be on the lookout for them.
I really frown upon this in a residential panel. Bob Vila makes everything look so simple everyone is starting to think they can do it themself.