Ultimate Guide: Wiring, Updated 10th Edition (eBook)

FUSE AND CIRCUIT BREAKER CAPACITIES

1 Before you label anything in your service panel box, make a scaled drawing of every room in your house. Draw the location of all the receptacles, light fixtures, switches, and appliances, and note where all the cabinets and furniture are positioned.

2 Once all the circuits are identified, go to the service panel and mark which breakers go to which circuits using stick-on labels. Then test each circuit by turning off the power, plugging in a radio (that’s turned on) to any given outlet, and then turning the power on at the panel to see if the radio plays.

3 If you are working by yourself, adjust the radio to a high volume so that when you turn on the power you can hear from the service panel area if the radio comes on.

4 As you go from outlet to outlet, note on your room drawings which ones occupy which circuits. You’ll need help to check if lights and ceiling fans turn on when you switch the breakers.

5 You will also need help from someone to check any appliance circuits. To do this with a range, for example, first turn off the breaker; then have a helper turn on the range. Next, turn on the breaker and see if the range comes on.

CHECKING FOR DAMAGE

You can easily diagnose a blown fuse element by looking through the fuse glass. A burned element suggests an overload; a broken element and darkened glass suggests a short circuit.

When a plug fuse is blown, the fuse shell may also be damaged. Check it for signs of burning and arcing.

A damaged plug fuse will clearly show marks caused by burning and arcing.

Burn flashes in a circuit breaker panel are a telltale sign of serious damage.

DESIGNING A KITCHEN WIRING PLAN

A WIRING PLAN must accommodate lighting fixtures, outlets for small appliances, and other devices that are often moved from one area to another, and outlets for large permanent appliances, such as dishwashers, washing machines, and electric ranges.

Creating the Plan

A kitchen probably requires the most complicated plan. For clarity and ease of viewing, we’ve provided two wiring diagrams: one for small-appliance outlets and the other for general lighting outlets. The National Electrical Code defines a general-purpose branch circuit as a circuit that supplies two or more receptacles or outlets for lighting and appliances. An appliance branch circuit is a circuit that supplies energy to one or more outlets to which appliances are to be connected and that has no permanently connected lighting fixtures that are not a part of an appliance.

As a minimum, Section 210.52(B) of the NEC requires that the dining room, pantry, and kitchen, including countertop receptacles, be supplied by no less than two 20-ampere branch circuits. Remember, the NEC provides the minimum requirements. It is recommended that more than two circuits be provided for these areas. However, these circuits are allowed to also supply the other receptacles in the dining room, pantry, and kitchen.

Section 210.52(C)(2) notes that receptacles used with appliances on top of the countertop for a kitchen island or peninsula when the receptacle is below the countertop surface are now optional, but if the branch circuit receptacles are not installed at the same time as the cabinets, additional receptacles can be added using an approved wiring method, such as conduit, raceway, or cable. This method must extend to the island or peninsula and must be terminated using an approved junction box and cover.

Gas ranges, such as the one shown here, require a 15-amp circuit to control clocks, burner ignition devices, and lights. For electric ranges, use a 50-amp range receptacle placed on a dedicated circuit.

SMALL APPLIANCE BRANCH CIRCUITS

Countertop Receptacles. Place receptacles so that kitchen appliances supplied with 2-foot power cords, such as toasters, coffee makers, and electric griddles, can reach a receptacle without the use of an extension cord. For example, there must be a receptacle within 2 feet of the end of the counter. There must be a receptacle within 2 feet from each end of the sink. The maximum distance between receptacles is 4 feet. Therefore, if an appliance is placed between the receptacles, the 2-foot cord can reach either receptacle. The spacing around an inside corner is measured on the top of the counter along the wall line.

GFCI Protection. To protect users of kitchen appliances in the vicinity of water, Section 410(A)(6) requires all kitchen countertop receptacles to be provided with ground-fault circuit-interrupter (GFCI) protection, regardless of how far they are located from the sink. Provide GFCI protection by one of two methods. Either install a GFCI receptacle as the first one in the circuit and connect regular receptacles to the load side of the GFCI, which will protect those receptacles downstream, or install a GFCI circuit breaker to protect the entire circuit.

Section 210.8(A)(6) requires GFCI protection in dwelling unit kitchens. Any 125-volt up to 250-volt receptacles in a residential kitchen must be GFCI protected. This includes branch circuit receptacles on the walls of the kitchen, even if they’re not in the vicinity of the sink or other countertops.

The appliances listed in Section 210.8(D) were added to the GFCI protection requirement for branch circuit receptacles covering 60-volt and 150-volt or less. This includes all wall surface and countertop receptacles, wall ovens, microwaves, dishwashers, electric ranges, counter-mounted cooking units, and clothes dryers that are hardwired or connected to a branch circuit receptacle via a cord. The best option is to purchase and install GFCI/AFCI combination breakers.

Lighting. You will notice in the wiring diagram that there are no lighting outlets on the 20-ampere small appliance branch circuits. Lighting should be provided by 15-ampere circuits. Arrange the lighting circuits in such a manner that should one circuit fail, the space will still be at least partially illuminated by lights on another circuit.

Plan on installing three-way switches in such a manner that lights can be turned on in the adjoining room before turning off the lights in the room that you are leaving. Should table or floor lamps be desired in the kitchen or dining area, install switch-controlled receptacle outlets that are supplied by a 15-ampere circuit.

Section 210.70(A)(1) has added laundry areas to the list of rooms in a home that must have at least one lighting outlet controlled by a listed wall mount control device at the entrance to the laundry room. The laundry room may not use a switched wire receptacle for the lighting outlet. This...