First, only 14 (not 12) gauge wires are to be inserted in the "quick-wire" holes available on the back of many receptacles and switches.
Second, there is a different kind of hole on the back of some styles of receptacle that will not hold on even to 14 gauge wires; these rely on your tightening the side-screws to hold the wire solidly in those holes. The most common mistake can happen when the old switch had three rather than two black wires connected to it, even though it was a regular "single-pole" (not 3-way) switch.
When you connect the new single-pole switch up, you can get confused by the new green screw they come with and hook one of those blacks to it.
The result will be: Don't connect any black to the green screw.
Even if the upgrader is aware that the outlet has been switched in this way and duplicates the exact connections of the old one, they may not know to break off the metal tab on the "hot" side of the new receptacle, which isolates the top and bottom halves.
The result would be a switch that has no effect: all the formerly switched outlets will always be live.
That screw is meant to be given a (bare) ground wire attached to the bundle of grounds, if any, back in the electrical box.
Instead, two particular blacks should connect to the non-green terminals at one end of the switch and the third to the other end, like they were on the old switch.Our free calculator uses up-to-date, trusted data to estimate typical subcontractor costs for a GFCI Outlet Installation project.For a basic 6 receptacles project in zip code 47474, the benchmark cost to Install a GFCI Outlet ranges between 6 - 8 per receptacle. Set Project Zip Code Enter the Zip Code for the location where labor is hired and materials purchased.2.The number, color, and function of the wires at an outlet can be confusing if the original connections are lost track of.Whether the attachment method chosen is screws, push-in holes, or pigtailing with wire connectors, enough insulation must be stripped off the wire for good metal-to-metal contact, and wires should be tugged on to check tightness. Be aware also of two other matters to do with new receptacles.The cost estimate includes: Expect to pay in the higher end of the price range for a licensed, insured and reputable pro - and for complex or rush projects.