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JohnsPop · Mar 6, 2009, 07:28 AM

I was at Home Depot yesterday looking for some screw in type fuses and saw some that had a little reset button on them. Are these safe? I was replacing a 30A fuse and they only had 20A resettable fuses so can I just use those since most breakers in modern panels are 20A anyway? These were for a tenant so it would be nice to have a fuse they can just push a button on and reset without having to unscrew a fuse and put in a new one. Thanks!

Pat

codyman144 · Mar 6, 2009, 07:39 AM

Fuses are not the best (or safest) option first of all, you should upgrade to a breaker panel. But if you are going to use fuses I think the type with a reset button would be just as safe as a normal fuse.

You absolutely cannot replace the 30 AMP fuse with a 20 AMP one. What does this particular circuit power and do you have an idea what size wires are coming off it? I am a little concerned here that the 30 AMP might be in error.

ballengerb1 · Mar 6, 2009, 08:23 AM

There is nothing unsafe regarding these fuses. This is old technology. Long since replaced with breakers, but they are safe. Yes you can install a 20 amp fuse in place of the old 30 amp device, it will likley pop more often if the load nears 20+ amps. The wiring will be 100% safe. I would do some exploring at this point since a 30 amp fuse is very unusual in a residential setting. Open the panel and check the size of the wire, a 30 amp circuit needs at least a 10 gauge wire, anything lighter will heat up and fail with a 30 amp load.

JudyKayTee · Mar 9, 2009, 10:14 AM

Originally Posted by ballengerb1

There is nothing unsafe regarding these fuses. This is old technology. long since replaced with breakers, but they are safe. Yes you can install a 20 amp fuse in place of the old 30 amp device, it will likley pop more often if the load nears 20+ amps. The wiring will be 100% safe. I would do some exploring at this point since a 30 amp fuse is very unusual in a residental setting. Open the panel and check the size of the wire, a 30 amp circuit needs at least a 10 gauge wire, anything lighter will heat up and fail with a 30 amp load.

Are breakers safer than fuses?

stanfortyman · Mar 9, 2009, 10:39 AM

You certainly can replace a 30 amp fuse with a 20, but as stated, I seriously doubt the 30 was correct in the first place.
Typically no lighting, and definitely no "standard" receptacle, circuits in a home can have 30A fuses or breakers.

IMO those breaker fuses are MUCH safer in a rental since they are less likely to be replaced by the wrong size.

Originally Posted by JudyKayTee

Are breakers safer than fuses?

This is a question that is difficult to answer. From a purely basic standpoint fuses are safer. Fuses almost never fail on the closed position.

For other reasons breakers are safer. It is not as easy to swap out a 15 or 20A breaker for a 30 like in the OP's situation.

ballengerb1 · Mar 9, 2009, 11:33 AM

Breakers are safer than fuses from the installation stand point and they are more convenient. A breaker can be reset with just a flip of the switch. A fuse must be unscrewed and replaced. When the fuse is out there is an expose live spot but you'd have to stick your finger inside to get a shock. Some folks, not bright ones, insert a coin when a fuse blows. This will restore the circuit but it is not longer fused and is unsafe.

JohnsPop · Mar 15, 2009, 07:17 AM

Yep, it's a rental and you know hell will freeze over before they replace that panel. :-) It just always gives me the heebie-jeebies unscrewing and screwing fuses. With the older wiring I agree that a 20 would be safer than a 30 and if they trip it, at least they can just push a button instead of having to buy a new fuse all the time.

On another note, my neighbor has a fuse panel as well and ALL of her fuses are 30's. I guess I should tell her she might want to move down as well.

I bet y'all are right that someone put the wrong size in at some point and then everyone else just kept replacing them with the same size. I don't know what size wire is in either but I'll check on it. I know my neighbor's wiring coming off the panel is fabric covered but don't know about the rental property. Thanks for all the responses!

Pat

KISS · Mar 15, 2009, 08:47 AM

There is very good information here.

What basically happens with fuses, is that it's easy to replace with the wrong size and sometimes only removal is the only way to determine if they fail. If they are replaced with the wrong voltage rating, e.g a 32V fused used in a 250 V rating application they can fail shorted due to arc over. This type of failure would not occur in a house panel, but it is a failure mode. Intermittant fuses are also possible, but rare.

With house panels, there is a non-removable insert that can be used that restricts the size of the fuse that can be used.

Replacing cartridge fuses can be dangerous as well although most of the old panels had pull outs.