07/22/2018
In the course of doing service calls, some of these are for customers wishing to upgrade from fuses to breakers. ( typically from 60A or 100A, up to 200A ) I have also had customers who just wished to change from fuses to breakers, but with no increase in ampacity. They were told breakers are much safer. After taking a look at their panel, which was done very professionally,.....still had room for expansion, and no visible problems at all. I said i would recommend to leave the panel in place. I then explained a few things to them as to why i suggested this. ( I also asked if their insurance company had recommended this, and that was not an issue ). The advantage of fuses, over breakers, is that fuses are an electrical device. There are no springs, contacts,as in breakers, which may have operational issues as they get older. ( most electricians have been breakers that will not trip, even when shorted to ground ) Good practice is to turn each breaker off and on, once a year to cycle the mechanism. However, in most households, this is not done. A fuse has a metal strip, which will blow or open at a pre - determined level of current.Since its not mechanical, it does not have to be cycled. Unlike a breaker, which if tripped, can be turned off to reset it....then turned back on.....the fuse must be replaced, as its a one time deal. Do NOT confuse the small breakers which look like a fuse, but have a reset on the front of them. They look like a fuse, but note the info on the front, its a resettable mini - breaker.
The disadvantage of the fuse, compared to the breaker, is that it is very easy for the home owner to swap out fuses and bump up the size if there is a problem. Open the front door on the panel, unscrew the 15A, and put in a 20A. Problem solved? . So they may think. If the fuse is blowing, there are reasons for this happening. It could be overloaded, eg, too many things on that circuit drawing over the 15 amp, which would cause it to blow. Putting in a 20A may appear to solve the problem, BUT the problem is that the wire is a certain size, and can only handle so many amps safely. Inserting a larger fuse, and allowing more current flow, could create a potential fire hazard. Well, see the picture of the different colored rings shown? These are fuse rejection rings. On a 15 amp circuit ( a blue fuse ), this ring would be screwed into the base, then the fuse inserted. The blue ring allows only a 15 amp fuse. Since the connection tip on a 20 amp is larger, it will not make contact to the bus, and is thus rejected by the ring. Its a safety feature. However, not all panels have these.
Fuses 20 years down the road, will still work properly. If you have a fuse panel, and may have concerns or questions, call an Licensed Electrical Contractor ( LEC ), and ask for an assessment of your panel.