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Celebrate the humble fuse

Electricity is an integral part of our society — we can't do without it, and yet, our ability to safely utilize it rests primarily with a marvelous little invention called the fuse. Made of two metal contacts, bridged by a wire or strip of metal inside a protective container, these clever devices are the lynchpin upon which rests our modern electrical system.

From baby monitors to satellites, the humble fuse is all that stands between your electrical components and utter destruction. Without fuses, our fondness for electronic gadgetry, heat and light would render us in constant danger of fire, injury or death from electrical shock, and property destruction from meltdowns caused by electrical overload. But thanks to the fuse, our computers compute, our ovens heat, and our CD players make beautiful music, without threat of harm. So take a moment to contemplate your good fortune, and raise a glass to Edward V. Sundt, inventor of the modern safety fuse.

How fuses work 
When all is well, electricity traveling along a power wire flows smoothly through its fuse. If a sudden, dangerous surge of power threatens to annihilate your expensive amplifier, receiver or even windshield wipers, the fuse selflessly immolates its bridging element in a millisecond blaze of glory, breaking the circuit and effectively cutting off the power surge at the pass.

A fuse can blow when you've got too many appliances connected to a single circuit. For example, a circuit in my house overloads whenever I try to run the dishwasher and washing machine at the same time in cold weather. If you make a mistake while wiring a car stereo, and inadvertently create a short circuit, a fuse will blow to save the day.

How to replace a fuse
Modern houses have circuit breakers instead of fuses, so all you have to do to restore power is flip a switch. But if you live in an older home or have antique appliances, you may need to check for blown fuses. EHow has a great article that'll help steer you through.

Fuses are used extensively in your car's electrical system and are a significant element in car audio. Basic Car Audio Electronics has a very detailed article about fuses, but if you think you might have a blown fuse, here's where to begin:

  1. Inspect the fuse--you should be able to see the filament through the casing. Normally, a blown fuse will look blackened or discolored.
  2. Sometimes, you'll see an obvious break or gap in the element. More rarely, the break occurs near the metal contact, so damage to the fuse isn't immediately obvious. The element should seat absolutely level — if it's crooked, assume the fuse is blown.
  3. If you really can't tell, just replace the fuse with another of the same value and see if that fixes the problem. It's a good idea to keep an assortment of extra fuses in your toolkit.

Important note: If you have a circuit that consistently blows fuses, something's happened to change the current draw. Many people try to handle a wonky circuit by endlessly replacing fuses (which gets annoying), or by going to the next fuse value up (which is dangerous). Don't just keep replacing fuses, do it right and test your wiring using a multimeter to trace down the weak point in the system, or consult an expert for help.

Fuses come in all shapes and sizes and are made for just about any application imaginable. Don't forget to check out crutchfield.com for a great selection of fuses and other wiring accessories. We've even got some fuses that light up when they're blown, so you don't have to hunt for the bad one.

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