What is this? Never have seen it before.

There is a main disconnect panel at the exterior of the house and recent modifications (additions) to the house have occurred. The need for additional electrical demands were needed.

Is this a correct modification? Never have seen one of these (appears to be a junction device of some type) that is present.

Thanks in advance.

it looks from here that these places occurring before the main panel circuit breaker so the main circuit breaker on the exterior of the house exceeds the capacity of the small wires attached before the subpanel.

The devices are probably fine, but their location is the problem.

The added circuits are “over fused”.

It is hard to tell if that is a proper use of the tap rules from the pics.

Those are pre-insulated wire connectors. Think expensive wire nuts.

The bottom lines are the feed lines from the meter. The upper lines are the ones that distribute power to the house.

Notice the double taps on the left side neutrals.

Does this help?

The wire connectors have one wire and then TWO wires. Is that permissable?

No that is not allowed.
They should have made one of those knuckles.

Are you talking about split bolt connections?

If so, these are a substitute for a split bolt without all the taping.

One conductor per hole.

Yes that is what I meant but the neutral in the latter picture is a double tap.

Yes as Jim said one conductor per hole unless the connector is listed for more than one conductor, and the neutral is double tapped as Bob said. How are these conductors terminated on the other end?