Originally Posted by steve dunham
1) Porcelain keyless receptacles are not designed nor UL listed as a fuseholder
2) Edison base fuses are allowed to be used in only very limited applications
Plug fuses if used should be type S to prevent tampering or overfusing
3) Porcelain keyless receptacles are normally rated for 660 watts ( approx 5 amps at 125 VAC) The wattage limit has more to do with the heat generated by an incandescent lamp
4) If the fuseholder is wired with reverse polarity than the screw shell of the fuse becomes a shock hazard
5) It appears the previous owner knew just enough to be dangerous
6) If his/ her exposed electrical work is that sloppy only God knows what he / her did where you can't see it
+1 to ALL of these.
To be honest I would just remove what is there and start over - electrical wiring is really not that difficult to do correctly, and a project on the scale of your boler
is an ideal way to learn - because it's small and relatively simple. If you want to hire someone to do it, that's fine too, but I'm just suggesting that there's no need to be afraid of tackling it yourself. You can do it
I had a similar rat's nest of wiring in my trailer on the 12v side (I think just the battery
leads had been spliced about a dozen times, and none of it was even still connected to the 12v lights
in my trailer - it seems that at some point someone added alligator clips inside the upper kitchen cabinet so a smaller battery
could be hooked up) and it was easier to just start over and run fresh wires than to try to "fix" what was already there and deal with corroded wiring and other problems. The 120V AC side was less sketchy looking - my trailer only had one circuit breaker and one outlet to start with. I did replace that outlet since it was worn out and not "gripping" anything plugged in particularly well.