In Pennsylvania, a home inspectors primary job is to find “material defects”. A material defect, as defined by Pennsylvania law, “is a deficiency in a component of the house that will significantly lower the value of the house or that poses a threat to the health or safety of its occupants.” Below is a picture of an old fused service box and two sub panels that should have been replaced or upgraded years ago. Fuse boxes are fine. Fuses can provide as good or, some say, better over-current protection than circuit breakers, but these panels are simply too small for the demands of the house, which now has central air and a rear addition. Instead of putting in a new panel, the home owner added circuits any-which-way, creating a dangerous situation.
At the bottom of the panel, terminals are double and triple tapped for lack of enough places to connect a terminal.
The sub panel is also over crowded with double taps and the fuses are all 30 amp fuses which are too large for regular household circuits.
But back to the scorching at the top of the panel. The scorching is upstream of the fuse blocks, which is to say, it is overheating in the service entrance cable before the fuse where the fuses can’t blow and turn off the power.
This service entrance cable was newer where it leaves the meter box. Generally, it is easy to guess the location of the panel while standing outside: its within a few feet of the meter on the inside of the of the wall–” as close as practicable” says the code.
But at this house, the S.E. cable travels about 30 feet hidden in the ceiling before it connects to the panel. And if you look at the cable as it enters the panel, it is an old cable. So the service entrance cable is spliced somewhere in the ceiling.
The long run of the service entrance cable should be protected by a circuit breaker at the meter, but then the panel would be a subpanel, not a service panel…and that is another story.