Electrical Panel

Inspecting a house built in 1975. The panel had this inside that jumped over to the main service panel. Anyone know what this is? Thanks

Hmmm, is this related to an alternative power source being used?
What is the reasoning?

The best idea I have for you is that it was a very crude attempt to control an automatic start for some type of backup power source. When the ct ( current transformer) would not detect power, it probably ran a start relay that would turn on a generator. Todays automatic transfer switches make this unnecessary and much safer than what is pictured,

A CT measures a scaled down portion of the power consumed. A factor is used to determine the true power used. Not unlike an architect scale is used to show something full size.