One New Service Coming Up

Your service panel is the primary distribution center for all the electrical currents in your house and yard. It connects your CD player, lava lamp, and 27-speed blender to your utility’s service lines. Fuses serve the same purpose as the circuit breakers in a modern service panel, but they are considered dated and no longer are installed for residential purposes. Some old fuse services are as small as 60 amps, which is hardly adequate for modern electrical demands. The National Electrical Code calls for a new service to be a minimum size of 100 amps.
There are two types of electrical services:

➤ Overhead service
➤ Underground service

Most older services are overhead. That is, the utility company uses overhead service conductors, usually from a utility pole, that often connect to a service mast on the outside of your house. An underground service, commonly found in new housing, is buried. Each must follow prescribed installation procedures.

What to Do When There are Power Outages?

You can’t do much to control power outages, but you can control what happens when the power comes back on. Unplug your computers and television sets, even if you have surge suppressors. The suppressors should take care of any initial charge from your electrical system, but unplugging these appliances guarantees that you won’t have any problems. Make sure any kitchen appliances that might have been left on, other than your refrigerator, are shut off. Any heat-producing appliance, such as an electric blanket, a heating pad, or a portable heater, also should be shut off, lest you forget about it and it stays on while you’re not home.

General Precautions in Working with Electrical Installation

Einstein considered common sense to be all the prejudices you acquire before the age of 18. (This was the belief of someone who apparently had to be reminded by his housekeeper to dress warmly before venturing out into Princeton winters.) Semantics aside, a certain amount of common sense should be applied to your electrical dealings.
Precautions for electrical appliances, devices, and wiring include the following:

• Buy only items that are UL-listed or approved by another accepted testing agency.
• Keep children from playing near portable heaters and kitchen appliances.
• Use kitchen and bathroom appliances on or near dry surfaces only.
• Keep combustible materials such as clothes and curtains away from heaters of any kind.
• Never cut off the grounding pin from a three-pronged plug.
• Never file down the larger prong on a polarized plug.
• Use child-resistant caps in unused receptacles.
• Install smoke detectors.
• Make sure the contact between a plug and a receptacle is solid and tight.
• Allow plenty of free space around computers, televisions, and stereo sound systems to prevent them from overheating.
• Keep metal ladders away from all power lines.
• Stay away from any downed power lines.
• Have your electrical system inspected if it’s more than 40 years old and you have no record of a recent inspection.
• Make sure all switches and receptacles have cover plates.
• At the very least, install plug-in GFCI receptacles into existing bathroom and kitchen receptacles that do not have grounding.
• Make sure light bulbs are the correct rating for their lamp or fixture. (Excessive heat can be a fire hazard.)
• Unplug portable appliances when they’re not in use, especially those near sinks. (You can be electrocuted if they fall into water—even if they’re turned off.)
• Leave electric blankets untucked.

Beware of Fire Hazards

Fuses and circuit breakers are designed to protect you from inadvertently overloading a circuit. When your loads demand more current than the circuit is designed to handle, the circuit breaker will trip or the fuse will blow. This prevents the conductors or wire from overheating and causing a fire. A conductor can only offer a certain amount of resistance to a current; if there’s too much current, the conductor can heat up enough to melt its insulation.
A homeowner can create a dangerous situation by replacing a fuse or a circuit breaker with one of larger amperage, thus allowing more current to flow through the wires than they can safely resist. A fire can start without tripping the breaker or blowing the fuse because the larger-amperage fuse cannot sense the problem. Some signs of a potentially overloaded system include …
➤ Thirty-amp fuses used for lighting circuits.
➤ The use of extension cords as permanent wiring.
➤ Dimming lights when appliance loads go on.
➤ Excessive use of adapters that allow more than two loads to be plugged into one receptacle.
➤ Multiple service panels and sloppy wiring practices.

Power Cords

Any cord-and-plug combination is subject to damage and wear. Lots of pulling and twisting, especially when a plug is pulled out by the cord rather than by grasping the plug itself, can cause the wires inside the insulation to break. This is particularly true with lamp cords because they use wire composed of multiple strands with a very small gauge. If the insulation protecting a cord cracks open, you could get a short circuit. It’s usually a better idea to replace these cords than to repair them.
Although it is less likely that you’ll ever have to replace a 240-volt appliance cord, these also can be changed out:

• Unplug the cord and unscrew the end that’s attached to the appliance, noting which wire (by color) went with which screw.
• Buy an exact replacement for the cord and plug.
• Connect the new cord to the terminal screws on the appliance, noting any color coding on the screws to match the individual wires (black to black, and so on).

Short Circuits

One telltale sign of a short circuit is black, smoky residue on switch or receptacle cover plates. Frayed or damaged cords and plugs also can be sources of short circuits. You need to check further for the source of the problem if your circuit goes dead and …

➤ You cannot find any visible signs of an electrical short.
➤ The circuit is not overloaded.

Before replacing the fuse or resetting the breaker, turn off all the loads and unplug everything from the receptacles. If the new fuse blows or the breaker trips right away, your problem is either in one of the devices (a switch or a receptacle) or in the wiring itself. To make sure the current is dead, remove all the cover plates and examine each device for charred wires or black residue. Clip the ends of any affected wires, strip off sufficient insulation, and install a new device. Replace the fuse or reset the breaker, and test the circuit again.
What if the circuit doesn’t short immediately after you set the breaker or replace the fuse? In that case, activate each load one at a time and then turn each one off. Check the load that eventually causes the short. The problem will be either in the fixture or appliance itself or in its wiring. Replace the offender and check the circuit again. If it still shorts out, you have a problem in the wiring itself and should call an electrician. Shorts in the wire almost always are at the device or fixture box, so the problem should be visible when you do your own inspection. Sometimes, however, the problem is caused by a splice or junction box buried in the wall and is therefore unnoticed upon first inspection. In the case of a plug-in appliance or lamp, if the circuit goes dead as soon as you insert the plug, you can assume the short is in the cord or the plug (both of which can easily be replaced). If the short doesn’t occur until after the appliance is turned on, the problem isn’t in the cord or the plug but in the appliance itself. You should then repair or replace the appliance.

Hot Electrical Equipments

The cover plate on a light switch or receptacle should not feel excessively warm and certainly should not be hot. A dimmer is an exception because dimmers dissipate the heat from dimming through the fins of the dimmer and often transfer some of that heat to the screws holding on the cover plate. Cords and plugs shouldn’t feel hot, either. Heat is a sign that the load is demanding current in excess of the ampacity of the electrical cable and/or the plug and cord attached to the load. If you replace a 60-watt light bulb with one of a larger wattage (one whose wattage exceeds the rating for the fixture), the wire or cable will still supply the current, even if doing so makes the fixture dangerous.
Heat signals that you should examine the total load on a circuit or a cord and plug.
In the case of a hot circuit, you should …

• Make sure the circuit breaker or fuse is the correct amperage for the circuit itself and the cable or wire that forms the circuit.
• Total the combined load on the circuit.
• If the load exceeds the circuit’s design, reduce the load. The real danger of an overloaded circuit is a wire heating up unseen inside your walls to the point where it can start a fire.