John, how are Multi-Wire branch circuits served from a single winding affected by harmonic distortion?
The harmonics would be the same on both sides of zero and would cancel the same as current cancels in any equal current flow.
Power quality would be a concern other than a shared netral when talking about single phase services.
Dave, there are many reasons to use Multi-Wire circuits and yet the biggest reason not to is the "unqualified person" making a mistake.
A qualified individual will look at the conduit or cable entry before lifting a neutral, and if there is more than one ungrounded conducted present not tied to a common trip breaker, they would know this is the case.
Roger
