Thursday, December 17, 2009

What are fuses and circuit breakers??

Fuses and Circuit Breakers

Author: Jim Johnson

These days most newer homes a circuit breaker panel. Many older homes may still have the old style fuse panels. In either case, fuses and circuit breakers have the same job of protecting branch circuits from sustained short circuits and overloading. The most common circuit breaker and fuse sizes you're likely to have are 15 amp, 20 amp, 30 amp, and 40 amp. The circuits which supply lights and receptacles in your home are generally protected by 15 amp or 20 amp fuses or circuit breakers. Your stove or range would be protected by a 40 amp breaker while your clothes dryer would have a 30 amp breaker.

In older homes you will find a multitude of outlets all running off of one circuit which results in frequent blown fuses or tripped circuit breakers. Some homeowners think that if they install a larger fuse or circuit breaker their problems will be solved. While this may prevent blown fuses it creates a dangerous overload on the branch circuit wiring. Cables and conductors are rated by how many amps they can safely carry continuously. A #14 cable is rated at 15 amps and a #12 cable is rated 20 amps. If you were put in a 30 amp fuse or circuit breaker you will exceed the safe limits of the cable.

A dangerous situation may occur if a cable carries more current than it's rated for. Large cables, with less resistance, can carry more current than smaller cables, which have more resistance. It's like a garden hose, the larger the diameter the more water it can carry. The smaller the diameter the less water it can carry. When a circuit is overloaded the conductors will start to produce heat which in turn can melt the insulation covering and cause an electrical fire. Rather than installing larger fuses and circuit breakers, do it the right way by breaking up reducing the number of outlets on overloaded circuits.

These days houses are wired much differently with circuit breaker panels housing 32 to 40 branch circuits. The big advantage of circuit breakers is that they can be reset where fuses have only one life. To reset a circuit breaker first turn it all the way off and then you can switch it back to the on position. When a fuse blows you have to replace it. It's a good idea if your home has a fusebox to keep 1 or 2 spares of each size fuse right beside the fuse panel so that you can find them easily when needed. It is highly recommended that you replace your old fuse panel with a circuit breaker panel. A qualified electrician and an electrical permit will be required for this.

When prospective home buyers are interested in your home, or if they hire a home inspector, one of the important areas of concern is the electrical system. An old fuse panel that is overloaded will create a red flag. If you replace your old fuse panel with a circuit breaker panel it will be a big plus when you do decide it's time to sell your home.

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