Whether the electrical work for new construction or remodeling work is done by a licensed electrician, or by you, the homeowner, the proper procedure generally includes two reviews from an inspector who is employed by the community's building code office. Electrical inspections may also take place for other reasons, such as when you are considering buying a house or when you are putting your house up for sale.
Two Rounds of Electrical Inspection
The most comprehensive inspections occur when electrical work requiring building permits is being done, such as during construction of a new home or major room addition. Major remodeling work to a kitchen or bathroom also requires permits and electrical inspections. The goal of the inspections process is to make sure that the applicable electrical codes are being followed, to ensure that the installation is safe. In these instances, an electrical inspector will need to visit you on at least two occasions.
The first is called the rough-in inspection. This takes place when you have installed all of the electrical boxes, cables, conduit, and wires to the point that you are ready for the walls to be closed up by surfaces. This inspection needs to be done before the insulation is installed, so that the inspector has a clear view of all of the wire runs from service panel to fixtures and appliances.
The second inspection takes place when the house is complete, but before you are allowed to begin using the space. This inspection is called the final inspection. At this point, all of the walls are closed in, painting is finished, floors are complete and you are ready to install the furniture. Be sure that all of the circuits are functioning and every light fixture has been hung and is connected. If the inspector approves your work now, it means that it meets professional standards and that it is up to code.
Electrical inspections can be quite perfunctory and swift when an inspector is reviewing the work of a professional electrician or contractor that he knows and has worked with before. A level of trust develops between inspectors and skilled contractors, and the inspections may be little more than formalities. But you should expect a more detailed inspection if you are doing the electrical work yourself. There is good reason for this. Inspectors want to make sure that amateur work is being done "up to code" and is perfectly safe. This does not mean that you should fear the inspections. Inspectors simply want to make sure your work is safe, and they can be a great source of information. Should you make a mistake, you will have every opportunity to make the corrections, and the inspector will return as often as it takes to ensure the work is safe.
What Inspectors Look For
Here's a quick look at what an electrical inspector look for during their review of the work:
- Proper circuits: Your inspector will check to make sure that the home or addition has the proper number of circuits for the electrical demand of the space. This will include making sure there are dedicated circuits for appliances that call for them, particularly during the final inspection. Especially in kitchens, it is critical that there be a dedicated circuit that serves each appliance that requires one, such as the microwave oven, garbage disposer, and dishwasher. The inspector will also make sure there is the appropriate number of general lighting and general appliance circuits for each room.
- GFCI and AFCI circuit protection: GFCI circuit protection has been required for some time for any outlets or appliances located in outdoor locations, below grade, or near sources of water, such as sinks. Kitchen small-appliance outlets, for example, require GFCI protection. In the final inspection, the inspector will check to make sure that the installation includes GFCI-protected outlets or circuit breakers where the code requires it. A somewhat newer requirement is that most electrical circuits in a home now require AFCI (arc-fault circuit interrupters). The inspector will also check to make sure that this protection follows code requirements—either through the use of AFCI circuit breakers or outlet receptacles. While existing installations do not require updates, AFCI protection must be included on any new or remodeled electrical installation.
- Electrical boxes: Inspectors will check to see that all electrical boxes are flush with the wall and that they are large enough to accommodate the number of wire conductors they will contain, along with whatever devices will be contained. The box should be securely fastened so the device and box are secure. Homeowners doing their own work are well-advised to use large, spacious electrical boxes; not only does this ensure you'll pass inspection, but it makes it easier to complete the wire connections.
- Box heights: Inspectors measure outlet and switch heights to see that they are consistent. Typically, outlets (more correctly called receptacles) should be at least 12 inches above the floor and switches should be at least 48 inches above the floor. This, of course, is subject to certain allowances. For a child's room or for accessibility, heights may be much lower to allow for access.
- Cables and wires: During a rough-in inspection, inspectors will review how the cables are clamped in the boxes. At the point of attachment of the cable to the box, the cable sheathing should stick into the box at least 1/4 inch so that the cable clamps grip the sheathing of the cable, not the conducting wires themselves. There should be at least 8 inches of usable wire length extending from the box. This allows enough wire to connect to the device and allows future trimming to connect to replacement devices. The inspector will also ensure that the wire gauge is appropriate to the amperage of the circuit—14-gauge wire for 15-amp circuits, 12-gauge wire for 20-amp circuits, etc.
- Cable anchoring: Inspectors will check for proper cable anchoring during the rough-in inspection. The cables should be attached to wall studs to secure them. Keep the first staple no father than 8 inches from a box and then at least every 4 feet thereafter. Cables should be run through the center of wall studs to help keep the wires safe from penetration from drywall screws and nails. The horizontal runs should be at least 20 to 24 inches above the floor and each wall stud penetration should be protected by a metal protective plate. This plate keeps screws and nails from hitting the wire within the walls when the drywall is installed.
- Wire labeling: Although not required by code, some electricians and savvy homeowners label the wires the electrical boxes to indicate the circuit number and the amperage of the circuit. An inspector is greatly reassured when he or she sees this kind of detail in a wiring installation.
- Surge protection: If you have delicate electronic devices such as TVs, stereos, sound systems, and other such equipment, the inspector may recommend using isolated ground receptacles. This type of receptacle protects against current fluctuations and interference. Along with isolated receptacles, surge protectors, either individual or whole house protectors, will protect these sensitive electronic devices. When planning for surges, don't forget the electronic boards in your washer, dryer, range, refrigerator, and other sensitive appliances.
To save yourself the frustration and the heartache of making mistakes, it's a good idea to ask the inspector for the specifics of required circuits and for instructions before you begin any work. Some inspectors have specific preferences that may vary slightly from the official code requirements—and in this case, it is the inspector who is the law. The inspector will also greatly appreciate your obvious intention to do good work, and your installation will likely pass easily when he visits to review the work.
Electrical Inspections | City of Philadelphia Business Services.
Ground fault circuit interrupters (GFCIs): Safe Electricity.
What Is an AFCI | AFCI Safety.
46 CFR § 111.81-1 - Outlet boxes and junction boxes; general. LII / Legal Information Institute.
Fair Housing Act Design Manual, Office of Policy Development and Research (PD&R).