How to change a fuse
Before you begin, make sure your hands are dry, stand on a dry board or rubber pad, if possible, and have a flashlight with you.
• Disconnect lamps and appliances in use when the circuit went out.
• Open main switch (or open pull-out section of main panel in the service entrance) to cut off current while working at the branch circuit box.
• Identify the blown fuse. When a fuse blows, the transparent section becomes cloudy or blackened. Some older fuse boxes have small-diameter fuses that require an adapter in the receptacle. This adapter should not be removed, and you should purchase the correct-size fuse for this model.
• Replace the blown fuse with a new one of proper size. The smaller sizes screw in just like light bulbs. If the blown fuse is a cartridge type, located in the pull-out section, it can be removed and replaced with hand pressure. If the fuse is for an appliance greater than 120 volts, call an electrician. Some switches for such appliances as water heater, stoves, and clothes dryers will still be energized if they are fed from the panel, and improper fuse replacement could result in severe injury.
• Close the main switch or replace pull-out section to restore service.
• Throw away the blown fuse.
• How to reset a breaker.
• Identify the breaker that needs to be reset. It usually appears red on the toggle handle, and is not always in the OFF position.
• Move handle to OFF position.
• Push handle past OFF position.
• Return handle to ON position.
A brief, sudden increase or decrease in voltage (spike) can at the very least cause a loss of data on computers, and on a few occasions, damage sensitive electronic equipment such as microwaves, VCRs and televisions. Prolonged increases (surges) or decreases (sags) in voltage can cause significant damage to the equipment if not properly protected.
Computers are very sensitive to variations in the power supply. While these glitches are rare, they can damage your computer's hardware, crash programs or scramble data. To guard against power glitches, you should:
• Copy and file data periodically (save your work at least every hour).
• Make sure your home or business is properly grounded to send stray voltages into the ground, not into the computer.
• Buy quality voltage surge protectors to help protect against spikes in voltage. Ensure that the product is UL-tested and labeled as a surge-protection device. Also, be sure to buy a unit with an indicator light that shows the surge protection is still working. Surge protectors can fail after even one large voltage increase.
• During storms, unplug sensitive equipment, if possible.
• Install a filter to keep out noise and static interference caused by lightning, large electrical motors or other equipment.
• Install an uninterruptible power supply system (UPS) for the best way to protect computers or similar electronic devices against power failure, spikes, sags, surges, or data loss.
Ground Fault Interrupters
Chances are, if you have a newer home or have remodeled an older home, some of your outlets are protected by ground fault interrupters (GFIs). GFIs are usually installed in bathrooms, kitchens and outside outlets—usually any location near sources of water. These highly sensitive devices detect faults in the device plugged into the outlet and quickly shut power off to that outlet. This minimizes the possibility of electric shock or damage to electrical equipment. GFIs are often provided as wall outlets or sometimes as circuit breakers in a breaker panel box.
It is good practice to test the GFI monthly. It is also a good idea to test the GFI after power outages. To test a GFI outlet or breaker, follow these simple instructions:
• Plug a lamp into the outlet and turn it on.
• Push the TEST button—the lamp should go off. If it does not, you should have your outlet checked by an electrician.
• Push the RESET button—the lamp should go back on. If it does not, you should have your outlet checked by an electrician.