Roughing in Electric Wiring

The Steps Involved in Electrical Rough-in

By Mark J. Donovan

Roughing in electric wiring is the process of attaching electrical boxes to the framing and running electrical wire between them and the main circuit panel. Roughing electrical wiring should be based upon your architectural plans for the home. There should be a page or pages in the architectural plans that specify exactly where each light switch, outlet, and light fixture is supposed to go. The electrical wiring plans should also specify the wire gauge that should be used and where Ground Fault Circuit Interrupters (GFCIs) are required.

The wire gauge required for each circuit is dependent upon the expect load on the circuit. For example, a family room or living room typically only requires a 15 Amp circuit breaker that does not need to be on a GFCI circuit breaker.

This is due to the fact that a living room or family room typically has only lights or consumer electronics for electrical loads on the circuits. On the other hand a kitchen typically requires 20 Amp circuits that are on a GFCI circuit breaker. The reason for this is that typically higher current draw appliances such as toaster ovens, mixers, and blenders are used in kitchen counter outlets. The GFCI is required is due to the proximity of water.

When roughing in electric you often hear terms such as Amps, Volts, and Watts. All of these terms have something to do with effectively how much electrical power is provided to your home and the circuits within it. More specifically “Amps” is a measure of current flowing through an electrical circuit, “volts” is a measure of the difference in potential energy between two points, and “watts” is a measure of power required by an electrical load such as a light bulb or appliance. Most lights and consumer electronics can operate off of a 15 Amp 120V rated circuit breaker.

Larger appliances such as a clothes dryer, however, typically run of a 30 Amp 240V rated circuit breaker. Also, large appliances such as stoves, dishwashers, refrigerators, dryers, and washing machines, typically run off of their own separate circuit breakers.

During the electrical wiring rough-in, Romex cable electrical wire is run from the main circuit panel to the various circuits as specified in the plans. On average there is usually between 20 to 40 electrical circuits in each home. For example, there may be a dedicated Romex cable running between the main circuit panel and a living room. In the living room there may be a dozen electrical boxes (outlets, switches, and light fixtures) that are effectively all tied together back to the main Romex cable that is fed up from the main circuit panel.

Combined, all of these tied together electrical boxes represent a single circuit. Note, all gang type electrical boxes should be blocked in with framing to ensure they will not flex when a power cord or appliance is plugged into them.

Rough in electrical wiring is complete when all of the circuits have been run from the main circuit panel to the various circuits within the home. The Romex cables feeding each electrical box are typically pushed into the boxes and left un-stripped and unconnected to actual switches and outlets. Likewise, back at the main circuit panel the wires are left loosely hanging. After an inspection by the local building inspector of the rough wiring, and the insulation and drywall have been installed the electrician will then return and complete the finish wiring. As part of the finish wiring process he will tie all of the wires at the main circuit panel into the box with the appropriate circuit breakers, attach the electrical outlets and switches, mount light fixtures, and tie in the large appliances to their respective circuits.

For help on building a new custom home, see’s New Home Construction Bid Sheet. The New Home Construction Bid Sheet provides you with the knowledge on how to plan a custom home building project, and what to look for when hiring contractors for your new home construction. It also includes a detailed cost breakdown table and spreadsheet for estimating your own new home construction building costs.

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