I had a problem once with a 3phase (3fuzes) block with one fuse not working when installed. Came to find out that one of the fuse (clamps) contained in the fuse block was burned off the screw at the outfeed wire connection. 'Nuff to drive a guy nutty on a 160 deg. roof.
Glad to hear about your new email address. Gee, I am lost when I cannot count on a guy for moral support, from time to time.
John Old Maytag repairman.:)