Posts Tagged ‘fuse’

Fuses and circuit breakers are safety devices located in your electrical panel that help prevent overloading and fires. They stop the electrical current if it exceeds the safe level for some portion of the home electrical system. Overloading means that the appliances and lighting on the circuit regularly demand more electrical current than the circuit can safely deliver.

If the demand for electrical current exceeds the safety level, a fuse opens once and must be replaced to reconnect the circuit. A circuit breaker “trips” its switch to open the circuit, and the circuit is reconnected by closing the switch manually.
Fuses
Replacing a correct size fuse with a larger size fuse can present a serious fire hazard. Doing so will allow excessive current to flow and possibly overload the outlet and the house wiring to the point that a fire can begin. Be certain that correct-size fuses are used (if you do not know the correct sizes, have a qualified, licensed electrician identify and label the sizes to be used).
NOTE: Fuses should be rated according to the wire that makes up the branch circuit, not the connected load. Most of the screw-based fuses used should be 15 amperes. Ensure that all fuses rated higher than 15 amperes are compatible with the branch circuit wiring.

Consumers sometimes replace a fuse that repeatedly “blows” with a higher ampere rated fuse. Although the new fuse may not open, it also may not protect the branch circuit. Doing so masks the real problem of too high a demand being placed on the circuit. The fuse will not open at the appropriate load for that circuit. Instead of using an inappropriate fuse, take something off the circuit to bring the demand to an appropriate level. If fuses continue to “blow,” keep track of which branch circuits are affected and which appliances are in use when the power outage occurs. Consult a qualified, licensed electrician to correct the problem.

Circuit Breakers
Just like fuses, circuit breakers provide over-current protection by opening the circuit, or “tripping” when an unsafe level of demand has been placed on the circuit. Circuit breakers are also rated for various current levels, such as 15 or 20 amps. Breaker systems offer more flexibility for new protective technologies like ground fault circuit interrupters (GFCIs/ELCB) and arc fault circuit interrupters (AFCIs). They also offer you the ability to reset the breaker once tripped, getting lights up and running quickly to prevent accidents resulting from the lack of power in the home. Resetting a circuit breaker is quicker than replacing a fuse and avoids the hazards of over-sized fuses.

When resetting a tripped circuit breaker, be aware that your circuit breaker may trip to an intermediate position close to “ON” instead of the “OFF” position (sometimes it is difficult to see that it has tripped). To reset, move the switch fully to “OFF” and then to “ON.” Before resetting a tripped circuit breaker, turn off or unplug appliances or lamps on the circuit to bring the demand back down to an acceptable level.