Tuesday, December 29, 2009

? HOW DO ELECTRICAL SAFETY DEVICES WORK


Circuit breakers or fuses in your home electrical panel sense overcurrent conditions and short circuits and reduce the risk of fire in your electric wiring. When you overload a branch circuit by plugging in too many products, the fuse blows or the circuit breaker trips to shut off power.
Up-to-date single-family dwellings should be provided with at least one branch circuit that carries power to an outdoor outlet. Locate your outdoor branch circuit(s) on the listing of branch circuits on your electrical panel. (If you have no outdoor wall outlet, call a qualified electrician to install one.) You should find the amperage on the circuit breaker or the fuse.
To figure out whether a combination of products will overload a branch circuit, add up the power ratings (watts) you plan to use at the same time on that circuit. The power (watts) or amperage of an electrical product is shown on its attached nameplate.
Volts (also on nameplate) x Amps = Power (wattage) For example: 120 V x 15A= 1800 W

Demanding more than 1800 W will overload a 15 ampere circuit.
Outdoor electrical products that may use a significant portion of the power a branch circuit can supply are electric lawn mowers, leaf blowers and snow blowers.
Be sure to figure total wattage in advance when you are planning an outdoor event. Add up the power ratings of everything you will use: garden lights, electric grill, hot tub and so on plus everything else on the circuit. If you exceed the circuit wattage limitation, you will likely trip a circuit breaker or blow a fuse which can cause hidden damage to the circuit. If necessary, plan to redistribute your power needs to more than one branch circuit, or reduce the electrical load to avoid the overload situation.
A short circuit in a product, cord or plug may also trip your circuit breaker or blow a fuse. If you can identify the product that is causing the problem, take it to a manufacturer-recommended repair facility. If you don't know what is causing your circuit breaker to trip or fuses to blow, call a qualified electrician.
A ground-fault circuit interrupter (GFCI) will disconnect power automatically when a plugged-in electrical product leaks electricity to ground. Outdoors, where water and electricity can easily inadvertently come together, a GFCI is a lifesaver, not a luxury. A GFCI is a simple device reasonably priced. If you are unsure about installation, seek a qualified electrician.
GFCIs protect against shock or electrocution when a plugged-in electrical product is dropped into a sink, pool, pond, puddle, or hot tub (a shock may be felt in the split second before the GFCI trips). A GFCI also cuts off current when a person contacts a product like an electric heater or an electric power tool, which may be "leaking electricity."
The National Electrical Code now requires GFCIs for protection in the bathroom, garage, kitchen and outdoor outlets of new homes.

No comments: