Residential electrical systems have gone through many changes over the years since they were first put into houses. Many of the changes have been safety related. One safety item that is about as old as the first house wiring is circuit protection.
Most everyone is familiar with circuit breakers or fuses, both are types of circuit protection. Fuses were the first form of circuit protection until they were replaced by circuit breakers or so most people believe.
Fuses have not been completely replaced by circuit breakers. In fact in some applications they are preferred. I spent over twenty years in manufacturing and all motor protection was by fuses, not breakers. Basically this is because fuses are quicker and more reliable than breakers. A huge surge of current can cause major and expensive damage. The slight delay in response from a breaker (or no response) can mean costly damage to machinery.
As a home inspector I occasionally still find fuse panels in homes. The first reaction by the buyer when I discover a fuse panel is it must be dangerous. My answer is not necessarily.
The problem most often with fuse panels is first of all they're old. Unlike wine electrical components do not get better with age. The next problem is there are circuits that are over fused. This has to be the most common and dangerous flaw with fuses.
Anyone who has ever lived in a house with a fuse panel knows the routine, myself included. The fuse blows and you go to the panel and change it. Later the same thing happens again, except this time when you change the fuse you put a BIGGER fuse in to replace the blown fuse or worse a penny in behind the blown fuse.
Red alert, red alert, DANGER, DANGER!
Fuses or circuit breakers blow or trip because the circuit is over loaded. When this happens you should find out why, not circumvent the protection. There is no question over protected or non protected circuits have caused innumerable fires.
These flaws were actually addressed in the 1940 National Electric Ccode. A requirement for new installations stated ; plug fuseholders must only accept a "Type S" tamper
resistant plug fuse. A Type S fuse was designed such that fuses rated 16 -
30 Amps could not be used in a fuseholder intended for fuses rated 0 - 15 Amps. The The tamper resistant plug fuse would also not allow a penny to bridge the fuse.
I have found tamper resistant fuse plugs in fuse panels almost never. Human nature being what it is, circuit breakers are more or less idiot proof compared to fuses. That being said, my recdommendation when finding a fuse panel is to replace it. Not because it may be unsafe, but more because the homeowner may mistakenly make it so.
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