Should I be concerned about a old fuse electrical panel?
Fuse panels were replaced by circuit breakers for new home construction in the mid-1950’s. This makes any fuse panel still in place at least 60 years old. Insurance companies that write homeowner’s insurance want to get a 4-point inspection report for homes that are more than 50 years old. Some companies require them for homes that are even younger. One of the four points is the electrical system and the 4-point form asks whether the electrical panel has fuses or circuit breakers. If the inspector checks the box for fuses—even for a sub-panel — you can be declined insurance until the panel is replaced.
There are two reasons why insurance companies will not accept a home with a fuse panel:
The serviceable lifespan of a fuse panel is rated at about 50 years. The panel is outdated equipment and at the end of its serviceable life. Fuse panels were not designed to deal with today’s electrical loads, current electrical codes and the need for various branch circuits throughout the home.
The base into which the screw-in fuses are inserted will accept any amperage rating in many panels, making it possible to over-fuse wiring rated for 15-amps with a 30-amp fuse when a homeowner is frustrated with blowing fuses.
With repeatedly blowing the fuse on a circuit. Overloaded wiring can get hot enough to start a fire. Insurance companies do not like fires.
Typically the screw-in, round type fuses with a clear viewing window in the center to indicate when they are blown are the only kind of fuse type that are problematic. Cartridge-type fuses, that have a long cylinder shape, are still approved, and useful when a delayed trip is desired.
In some older homes that have had an electrical service upgrade, a new circuit breaker panel may have been installed as the main panel, but their might also be an old fuse-type panel remaining in service as a sub-panel. You might only uncover the existence of the original fuse panel through home inspection as it may be located out-of-sight in a closet, behind furniture or other common house appliance’s obstructing its presence.
Why is a fuse panel dangerous?
When the wiring in a house is overloaded with too many appliances drawing current, it overheats and can start a fire in the walls or attic. Old electric panels with round, glass screw-in type fuses use a simple, dependable technology to avoid that problem: a small metal strip, visible through the window in the center of the fuse. It is calibrated to overheat and melt apart when amperage (current flow) exceeds the rating on the front of the fuse. If the metal strip in the window is not visible, that indicates the fuse strip has “blown” open and has shut off the circuit. The reason for concern is that the wiring for these older homes were designed for circuits rated for a 15-amp fuse. However, the base that the fuse screws into, called a “Type T” base will also accept a 20, 25, or even a 30-amp fuse allowing it to be fused at as much as double the rated safe load that the wiring is rated for.
Homes that were built with fuse panels in first half of the 20th century had a electrical system designed for the expected usage of the times. Only a few circuits were necessary for general appliances, connected devices and lighting. But due to the 1950’s era of Life is better with electricity. Homeowners began acquiring TV’s, home electronics, washing machine, dryer, and kitchen appliances. Some homeowners found that they began to have problems with their electrical system due to all the new appliances and devices repeatedly blowing fuses. It was soon discovered that replacing the circuit rated 15-amp fuse with a 25 or 30-amp fused solved the problem of blowing fuses. Unfortunately it created a bigger problem that stretched (metaphorically speaking) the homes wiring to the point of failure and can be traced to the root cause of electrical fires.
As a result of these house fires a new “Type S” fuse was created. It comes with its own base that locks permanently into the old “Type T” base and, once in place, only accepts a Type S fuse of the desired amperage rating. So, after a 15-amp Type S fuse is installed, no fuses with a higher rating can replace it. Although this new design was not foolproof.
Capacity – “Hey can you add a “….” circuit to my fuse panel?” – Nope!
Some older fuse panels are only rated at 60-amp total capacity. Many of these panels have multiple wires clamped under the same fuse lugs as there isn’t enough wire lugs to properly break up the circuits individually. It is for these reasons and a few others that insurance companies don’t want to write a policy for an older home with a fuse panel still in place.
Lets summarize and wrap this up. An old fuse panel is not garbage unless its not meeting its purpose of protecting associated wiring and connected devices from failure. If a homeowner were to live a somewhat minimalist lifestyle and does not have every new techy gizmo and new latest appliance connected to their electrical system chances are good that you wouldn’t have to change out your old fuse panel to a breaker panel. BUT… This implies that the electrical wiring and the electrical panel have been maintained and fuse’s are properly rated to the wiring they protect. The reality is that 99% (just a guess) of the people reading this article living in 2019 don’t live a minimalist lifestyle and prefer the luxuries of the time we live in. In this scenario it is much more likely that although your fuse panel may look safe it is actually inadequate to providing the protection and the volume of circuits that a modern breaker panel can. I would typically suggest changing the panel when you anticipate a home renovation or when adding a new major appliance. When purchasing a old home factor into your budget replacement of the electrical panel.
Start living in your “new” home with a safe new electrical panel that is up to the task of growing with your family into the future.