When building or remodelling a high-use room like a kitchen, it's particularly important that new designs comply with all pertinent building codes. While codes vary by state and even by municipality, many local codes use the International Building Code and the National Electrical Code as their sources. Familiarising yourself with either may help you to more easily understand and anticipate your own area's specific kitchen regulations.
GFCI, or Ground-fault circuit interrupters, help to avoid accidental electrocution. First, the electrical current comes into contact with a means to ground, such as a person standing on the floor and accidentally touching exposed wiring with a wet finger. As soon as this route to ground is sensed, the GFCI cuts off the electrical current. According to the National Electrical Code, all commercial kitchens must feature GFCI protection for all 15A- and 20-ampere, 125-volt receptacles. Likewise, in residential kitchens, all receptacles serving kitchen countertops must have GFCI protection.
Circuits and Switches
In the kitchen, breakfast room, dining room and pantry, all of the receptacles must be supplied by at least two small-appliance circuits of 20 amps each. These circuits must both power the receptacles located directly above the kitchen counter; code requires that a single circuit not serve all such receptacles. Additionally, these circuits must exclusively power lighting or appliances within the kitchen, pantry, etc. They cannot power appliances in any other rooms. Any large built-in appliances, such as ovens, stoves, dishwashers or garbage disposal systems must have a separate circuit from the small appliances and lights. There must be at least one light switch in the kitchen, as for any room. As in a bathroom, at least one light switch must operate a permanently installed light.
Pertinent plumbing code will determine the dimensions and specifications of your kitchen plumbing, such as the pipe and wire sizes and the sizes and types of fittings needed. The drain-waste-vent, or DWV pipes, typically install first, with water supply pipes and electrical cables easier to add afterward. While code regulations vary, the DWV pipes are usually either black ABS or white PVC. A new sink, located in the same location as the old, is permitted to use the old DWV pipes. If the new sink is located at a short distance, you may add extensions. The water pipes may also be placed in the same space as the DWV pipes, depending upon the code. Also depending on local code, the water pipes may either be copper, the most common material, or plastic in some cases.