I have a 1950s era house with knob and tube wiring and the round screw-in style fuses. One fuse in my house develops corrosion on the bottom of it (picture attached). It is this specific circuit that it happens to, not any of the others in the panel. A few years ago, this circuit at the fuse box failed catastrophically. An electrician moved the circuit to an unused fuse (i.e., the panel has 4 holes for fuses and one was not used at all). This is the one that is again developing this on the bottom.

Other than rewiring the house or fuse panel (I'm saving up for that), what can I do about this to make the circuit last longer (I assume this is what led it to blow)? My idea is cleaning/sanding, but I'm not really sure if that will scrape off a coating and I don't know what is happening or why.

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  • Hard to tell from such a low-res, out-of-focus image, but that looks more like a plated coating that has come off the contact. You can’t fix that by cleaning - the material that was there is gone.
    – nobody
    Commented Dec 12, 2023 at 14:45
  • What is the circuit for?
    – nobody
    Commented Dec 12, 2023 at 14:45
  • It is in the fuse box of my home. This circuit is for my bedrooms and bathroom.
    – racketteer
    Commented Dec 14, 2023 at 0:44

1 Answer 1


It doesnt look like corrosion to me. Its more like pitting. Which would happen if it was arcing. That would imply that

  • the fuse is not making contact properly
  • or the current is too high, making it heat up

I would suggest that you try to tighten it a bit further. If that is not possible then try to split the load.

  • Thank you for the suggestion. The pitting is on both the fuse and the holder, so it is arcing across. I thought I screwed it in all the way but maybe not. I'll try to tighten some more. I'm not sure how I can split the load without rewiring part of the house, which I'm starting to save up for. If the current is too high, wouldn't the fuse blow?
    – racketteer
    Commented Dec 14, 2023 at 0:46

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