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Statistics show that fuse panels have a significantly higher risk of causing a fire than breaker panels. This is usually due to the fuse being loosely screwed in, or the contacts corroding and heating up over time, or the wrong size fuse being installed, or the proverbial "replace the fuse with a penny" trick. Since breakers are more permanently installed, and have better connection mechanisms, the risk of fire is considerably less. Fuses are prone to explode under extremely high overload. When a fuse explodes, the metallic vapor cloud becomes a conducting path. Result? From complete meltdown of the electrical panel, melted service wiring, through fires in the electrical distribution transformer and having your house burn down. [This author has seen it happen.] Breakers won't do this. Many jurisdictions, particularly in Canada, no longer permit fuse panels in new installations. The NEC does permit new fuse panels in some rare circumstances (requiring the special inserts to "key" the fuseholder to specific size fuses) Some devices, notably certain large air conditioners, require fuse protection in addition to the breaker at the panel. The fuse is there to protect the motor windings from overload. Check the labeling on the unit. This is usually only on large permanently installed motors. The installation instructions will tell you if you need one.
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Last Update May 13 2007 @ 00:22 AM