First time with old style fuses in fuse panel

darsunt

This is the first time I've had to deal with old type screw in fuses. I have two questions:

1) Are you really supposed to shut off the fixtures before pulling out the fuses? Usually I test what part of the house breakers serve by seeing which lights go off when I click one off (my breakers panels are old and have no labels). It will take me a while to find the right fuse if I can't test them that way.

2) Are they safe to handle? I've read you unscrew them by holding the insulated outside rim.

Thanks

jwhite

If there is a large load turned on while you unscrew the fuse (or screw it in) there could be an arc inside the panel that can melt the fuse and the place where it screws into.

You handle them carefully so that you don't get burnt by the arc.

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Master Electrician

darsunt

Thanks. I was going to take precautions anyways, but now I know what I am guarding against.

I do switch breakers off and on all the time when lights are on. Is there any risk to this?

JohnJ0906

No. A breaker is designed to open under load... overload even.
You wouldn't want to REMOVE the breaker under load. This would be the equivalent of removing a fuse under load.

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John from Baltimore
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