fuses and breakers

[vptran]

Hello everyone,

I recently did some research on fuses, but am still unclear about certain characteristics of circuit breakers. What are the advantages and disadvantages of fuses versus circuit breakers? From what i have researched, fuses cost a lot less than breakers, but breakers can be resetted. What circumstances dictate you to use a fuse and not a circuit breaker and vice versa? I mean I'm still unclear why in certain situations, we use fuses and why other situations we use breakers. If anyone can clarify this for me, that would be really helpful.

Thanks.

 

[jtester]

There are a multitude of reasons to use fuses, and probably an equal number of reasons not to.

Pro fuses- can choose fuse size closer to load requirements of many devices like motors, hvac, etc.; often cheaper; often more readily available; easier to change size, ie a 40 amp to a 50 amp fuse;

Cons- fuses will allow single phasing on sensitive circuits; require a bit more expertise to restore power; etc.

I'm sure there are a million more, this is just a start.

I usually won't use fuses where single phasing is a problem, I won't use them where maintenance people are unskilled or not present, other than that I use fuses in many applications.

Jim T

 

[steve66]

Fuses may be cheaper than breakers, but the distribution equipment that houses breakers is usually cheaper and smaller that similar equipment made for fuses.

Can you even buy a fuse type branch circuit panelboard anymore??

Steve

 

[jim dungar]

Asking why fuses versus breakers is a lot like asking why "diesel versus gasoline".

The technical engineering answer is " It all depends..".

Fuses are faster on some faults and breakers are faster on others. Breakers with integral ground fault elements are less expensive to coordinate than are fuses.

Just don't fall into the trap that one is always better than the other.

In industries in this area, it is very common for all of the service entrance and feeder equipment to be breakers and the process branch circuits to be fusible.

 

[DaveTap]

Can you even buy a fuse type branch circuit panelboard anymore??

Steve

EBay?

 

[haskindm]

If the label on a piece of equipment (air conditioner for example) says maximum FUSE ampacity, then the equipment must be protected by a fuse. If it says maximum overcurrent protective device, or maximum fuse OR circuit breaker ampacity (Usually HVACR Rated breaker) then either may be used.

 

[petersonra]

Many industrial plants want absolutely nothing to do with fuses if they can avoid them. As a general rule, fuses blow at 3 am, you have no spares, and the electrical supply house is closed. Circuit breakers can just be reset.

 

[mdshunk]

With a fuse, you can get almost a designer or "botique" type specific fuse for a very specific application. This is harder to achieve with a breaker, save for expensive programmable one's.

 

[vptran]

thanks guys, all of your comments have been really helpful.