Service Panel
-
Maintain a minimum 30” x 36” of clearance on front of the service panel.
-
Ground all 120-volt and 240-volt circuits.
-
Match the amperage rating of the circuit when replacing fuses.
-
Locate service panels and sub panels a maximum of 79” above floor level.
-
Use handle-tie breakers for 240-volt loads (line to line).
-
Close all unused service panel openings.
-
Label each fuse and breaker clearly on the panel.
Electrical Boxes
-
Uses boxes that are large enough to accommodate the number of wires entering
the box.
-
Locate all receptacle boxes 12” above the finished floor (standard). For
special circumstances, inspectors will allow switch and location measurements
to be altered, such as a switch at 36” above the floor to make them more
accessible for someone in a wheelchair.
-
Install all boxes and conduit fittings so they remain accessible.
-
Leave no gaps greater than 1/8” between wallboard and front of electrical
boxes.
-
Place receptacle boxes flush with combustible surfaces.
-
Leave a minimum of 8” of usable cable or wire extending past the front of the
electrical box.
Wire & Cables
-
Use wires that are large enough for the amperage rating of the circuit.
-
Drill holes at least 2” back from the exposed edge of joists to run cables
through. Do not attach cables to the bottom edge of joists.
-
Do not run cables diagonally between framing members.
-
Run cable between receptacles 20” above the floor.
-
Use nail plates to protect cable less than 1 ¼” from front edge of stud.
-
Do not crimp cables sharply.
-
Contain spliced wires or connections entirely in a plastic or metal electrical
box.
-
Use wire connectors to join wires.
-
Use staples to fasten cables within 8” of an electrical box and every 48” along
its run.
-
Leave a minimum ¼” (maximum 1”) of sheathing where cables enter an electrical
box.
-
Clamp cables and wires to electrical boxes with approved NM clamp. No clamp is
necessary for one gang plastic boxes if cables are stapled within 8”.
-
Label all cables and wires at each electrical box to show which circuits they
serve for the rough-in inspection.
-
Connect only a single wire to a single screw terminal. Use pigtails to join
more than one wire to a screw terminal.
Switches
-
Use a switch-controlled receptacle in rooms without a built-in light fixture
operated by a wall switch.
-
Use three-way switches at the top and bottom on stairways with six steps or
more.
-
Use switches with grounding screw with plastic electrical boxes.
-
Locate all wall switches within easy reach of the room entrance.
Receptacles
-
Match the amp rating of a receptacle with the size of circuit.
-
Include receptacles on all walls 24” wide or greater.
-
Include receptacles so a 6-ft. cord can be plugged in from any point along a
wall or every 12-ft. along a wall.
-
Include receptacles in any hallway that is 10-ft. long or more.
-
Use three-prong, grounded receptacles for all 15- or 20-amp, 120-volt branch
circuits.
-
Include a switch-controlled receptacle in rooms without a built-in light
fixture operated by a wall switch.
-
Install GFCI-protected receptacles in bathrooms, kitchens, garages, crawl
spaces, unfinished basements, and outdoor receptacle locations.
-
Install an isolated-ground circuit to protect sensitive equipment, like a
computer, against tiny power fluctuations. Computers should also be protected
by a standard surge protector.
Light fixtures
-
Use mounting straps that are anchored to the electrical boxes to mount ceiling
fixtures.
-
Keep recessed light fixtures 3” from insulation and ½” from combustibles.
-
Include at least one switch-operated lighting fixture in every room.
Grounding
-
Ground all receptacles by connecting receptacle grounding screws to the circuit
grounding wires.
-
Use switches with grounding screws whenever possible. Always ground switches in
kitchens, bathrooms, and basements.
By Room
Kitchens/Dining Rooms
-
Install a dedicated 40- or 50-amp, 120/240-volt circuit for a range (or two
circuits for separate oven and countertop units).
-
Install two 20-amp small appliance circuits.
-
Install dedicated 15-amp, 120-volt circuits for dishwashers and food disposals
(required by many local codes).
-
Use GFCI receptacles for all accessible countertop receptacles; receptacles
behind fixed appliances do not need to be GFCIs.
-
Position receptacles for appliances that will be installed within cabinets,
such as microwaves or food disposals, according to the manufacturer’s
instructions.
-
Include receptacles on all counters wider than 12”.
-
Space receptacles a maximum of 48” apart above countertops and closer together
in areas where many appliances will be used.
-
Locate receptacles 18” above the countertop. If the backsplash is more than the
standard 4” or the bottom of the cabinet is less than 18” from the countertop,
center the box in the space between the countertop and the bottom of the wall
cabinet.
-
Mount one receptacle within 12” of the countertop on islands and peninsulas
that are 12” X 24” or greater.
-
Locate at least one receptacle at table height in the dining areas for
convenience in operating a small appliance.
-
Do not put lights on small appliance circuits.
-
Install additional lighting in work areas at a sink or range for convenience
and safety.
Bathrooms
-
Install a separate 20-amp circuit.
-
Ground switches in bathrooms.
-
Use GFCI-protected receptacles.
-
Install at least one ceiling-mounted light fixture.
-
Place blower heaters in bathrooms well away from the sink and tub.
Utility/Laundry Rooms
-
Install a separate 20-amp circuit for a washing machine.
-
Install a minimum feed 30-amp #10 THHN wire for the dryer, powered by a
separate 120/240-volt major appliance circuit.
-
Install metal conduit for cable runs in unfinished rooms.
-
Use GFCI-protected receptacles, except for fixed appliances, such as freezers
or dryers.
Living Room/Entertainment Rooms/Bedrooms
-
Install a minimum of two 20-amp circuits in living rooms.
-
Install a minimum of one 15- or 20-amp basic lighting/receptacle circuit for
each 600 square feet of living space.
-
Install a dedicated circuit for each permanent appliance, like an air
conditioner, computer, or group of electric baseboard heaters.
-
Do not use standard electrical boxes to support ceiling fans.
-
Include receptacles on any wall that is 24” wide or more.
-
Space receptacles on basic lighting/receptacle circuits a maximum of 12 feet
apart. For convenience you can space them as close as 6 feet.
-
Position permanent light fixtures in the center of the room’s ceiling.
-
Install permanently wired smoke alarms in room additions that include sleeping
areas.
Outdoors
-
Check for underground utilities before digging.
-
Use UF cable for outdoor wiring needs.
-
Run cable in rigid metal or schedule 40 PVC plastic, as required by local code.
-
Bury cables 12” if the circuit is no larger than 20 amps. Bury the cable at
least 18” deep if the circuit is larger than 20 amps.
-
Use weatherproof electrical boxes with watertight covers.
-
Use GFCI-protected receptacles.
-
Install receptacles a minimum of 12” above ground level.
-
Anchor freestanding receptacles not attached to a structure by embedding the
rigid metal conduit or schedule 40 PVC plastic conduit in a concrete footing,
so that it is at least 12”, but no more than 18”, above ground level.
-
Plan on installing a 20-amp, 120-volt circuit if the circuit contains more than
one light fixture rated for 300 watts or more than four receptacles.
Stairs/Hallways
-
Use three-way switches at the top and bottom on stairways with six steps or
more.
-
Include receptacles in any hallway that is 10 ft. long or more.
-
Position stairway lights so each step is illuminated.
What Inspectors Look For
Electrical box faces should extend past the front of framing
members so the box will be flush with finished walls (left). Inspectors will
check to see that all boxes are large enough for the wires they contain. Cables
should be cut and stripped back so that 8” of usable length extends past the
front of the box, and so that at least ¼” of sheathing reaches into the box.
Label all cables to show which circuits they serve: inspectors recognize this
as a mark of careful work. The labels also simplify the final hookups after the
wallboard is installed.
Install an isolated-ground circuit and receptacle if
recommended by your inspector. An isolated-ground circuit protects sensitive
electronic equipment against tiny current fluctuations and interference.
Electronics also should be protected by either a plug-in surge protector or a
whole-house surge arrestor.
Click below for more options:
Working with Inspectors
Large Contract Jobs over $10,000
Evaluating Curcuits for Safe Capacity
Planning New Electrical Service
Understanding Electricty
Glossary
Installation Price