I have had two licensed electric contractors quote a similar job. One says I need more power to back sub panel and the other says no. Have 100 amp main in house feeding a 100 amp panel in detached mother in law suite which is run off a 60 amp breaker to feed the apt. I want to install split AC unit, washer/dryer and stove, microwave in the apt. Do I need more service to apt in rear? Do I need more service running to main house to feed apt?

Hello, I know that the resounding answer here is probably going to be "get an electrician"... which I am going to do in a week or so. But in the meantime I am really wanting to know what's going on here. I have one circuit in my house that is fairly overloaded. Amperage wise maybe not, but it's just going to too many lights. I'm trying to trim back this circuit and use other circuits to get power. I converted my stove from electric to gas a while back, and turned that 40amp 240v circuit into a subpanel. When I measure the voltage from either the 'overloaded' circuit or from a circuit on the sub, things look fine. However, when I measure across the hot wire from the sub panel and the neutral from the overloaded circuit, I am getting a lower voltage.... about 70V. Instinct tells me that this is wrong, but I don't have much AC theory under my belt and this is just boggling my mind. I wouldn't expect exact voltages, but a drop of 50 volts seems pretty weird. Anyone have any clue what may be going on here? I really appreciate any honest help here... as I said, I am having an electrician look at this soon. Dave Cincy, OH