The Service Panel

Also known as the “fuse box”, the service panel is the heart of the home’s electrical system.

Electric power from the utility company comes into the service panel through large electric wire called the service main. The service main is then divided into branches in the service panel and distributed through the house through the branch wiring. The branch wiring is controlled by electric breakers, fuses, or combination of both. The most important aspect of the electrical service is that it is large enough to meet the demands of servicing the household and that the service is grounded. The wiring in the service panel should be neat and the panel box should be clean of debris. When the main disconnect breaker is switched to the off position, all power to the entire house will be interrupted. The main disconnect breaker should match the capacity of the service wire. Only a licensed electrician should probe or insert any tool or measuring device inside the panel box.

Branch Wiring

The wiring that connects the electrical outlets and switches to the service main is called branch wiring. Most branch wiring is referred to as Romex. Modern Romex wire consists of hot, neutral, and a ground wire wrapped in a plastic-type jacket. The purpose of the ground wire is to direct stray electricity back to the service panel and thus help to  avoid accidental electrocution. Houses wired before the mid 1970s generally may not have a ground wire attached to each outlet or switch. This is referred to as a two wire connection. These circuits can be identified by having only two slots on the receptacle outlet. Several modern appliances, (refrigerator, microwave, water bed heater,) require a three prong outlet. Any two prong outlet may be upgraded to accept a three prong appliance by either installing a GFCI outlet or by having an electrician ground the circuit with a grounding wire. Three prong outlets should not be substituted for two prong outlets without proper grounding.

Aluminum Wiring

Between 1968 and 1972 many homes were wired with aluminum branch wiring rather than the standard copper wire used today. It has been well documented that aluminum branch wire is associated with fire hazard. Aluminum wire can be identified by its characteristic silver color and the symbol CU‑AL on fixtures and breakers. If there is only a small amount of  aluminum wiring, it could be replaced by a licensed electrician with copper wire. Otherwise, be sure that the proper connections have been made to the outlets and consider evaluation by a licensed electrician. Large gauge (>8 ga.) stranded aluminum wire is widely used for large appliances and service entrance conductors and is acceptable.

General Amperage Requirements

Bath Outlets              15        Workbench   20        Microwave Oven      20

Kitchen Outlets        20        Workshop      35        Garage Outlets         15

Dishwasher              15        Refrigerator   20        Computer                  15

Electric Range          35        Deep Freezer  20        Whirlpool                   20

Clothes Washer       20        Electric Dryer  30        Lighting                     15

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