At a recent home inspection in Mount Vernon, Washington, I noted dangerous double-tapping or electrical wires in the old electrical panel.  Double-tapping the main service entrance conductors (wires) at an older fuse panel is a definite safety issue that can lead to overheating of the undersized wires and at the lugs themselves.  Double-tapping is where two (2) electrical wires are connected under one screw or terminal in an electrical panel.  Further evaluation and repair by a qualified electrician was advised.  It would also be prudent to update the old fuse panel for improved safety.