How to Check Fuses in the Home
When power goes out to only one part of the home, the fault may be a blown fuse. Fuse elements are made for one purpose: to melt during current overloads, preventing possible electrical fires in the part of the house where the real problem occurs. Simply replacing a blown fuse won't always solve the basic problem. Power surges might blow a fuse, but also look for overloaded circuits and faulty appliances. Never replace a blown fuse with a fuse made for higher amperage, the U.S. Consumer Product Safety Commission advises. Does this Spark an idea?
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Instructions
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Locate the service box, which contains the circuit breakers and/or fuse panel for your home. Look for a gray metal box mounted on the inside wall of the garage, basement or utility room. The electrical service box should be near the house's electrical utility meter, which you'll find on an outside wall.
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Shine the flashlight over the fuses in the panel to do a quick visual check. Household circuits usually carry no more than 20 amperes and are fuse-protected with individual round ceramic- or glass-body fuses. Check the metal strips visible through the fuses' glass panels to see if any have clearly melted away.
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Grasp an obviously blown fuse by the ceramic housing, being careful not to touch metal parts of the fuse, and unscrew the fuse counterclockwise. Replace a blown fuse with a new fuse marked with the same ratings. Tighten by hand only.
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Reset the circuit breaker if all fuses appear good. Depress the circuit breaker switch to "Off" for two seconds before switching the circuit breaker to "On" to reset the device. Check to see if this restores power in the house.
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Look for the ceramic-body fuse that controls power to the part of the house with the outage. Most home systems clearly label each fuse location with the section of the house it serves. Remove the appropriate fuse from its socket.
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Turn the dial of the multimeter to "Ohms." Select one of the higher ranges like "100K." Check to make sure the meter operates by touching the tip of the red multimeter probe to the tip of the black probe. The needle on an analog meter shifts to the "Zero" end of the scale, while a digital meter reads either zero or only a few ohms.
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Place one probe on the threaded metal rim of the fuse base. Touch the center electrode in the bottom of the fuse's base with the other probe. Good fuses read nearly zero, while blown fuses show infinite resistance and don't change the meter's reading.
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Tips & Warnings
Turn battery-powered multimeters to "Off" after use, since the resistance measurement circuit depends on an internal battery. Leaving meters set to "Ohms" drains the battery.
If the fuse reads good but the circuit still doesn't work, try replacing the fuse with a new one of the same rating. Old fuses in damp basements often tarnish and cause intermittent connections. Taking them out and putting them back may fix the trouble, but a shiny new fuse works best.
Fuses that blow repeatedly indicate potentially dangerous problems elsewhere in the house. Call a licensed electrician if trouble persists, advises FirstEnergy Corp.
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Resources
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