The Circuit Detective    -  Replacing Outlets and Switches

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Pitfalls When Replacing Outlets
Or Upgrading Electrical


At some point in a home’s life, installing new receptacles, switches, and light fixtures will be a good idea. The originals may be out of fashion, but they also wear out regardless. The homeowner replacing outlets and switches without a glitch is rare. I thought of titling this page "I Messed Up". Here are some of the things that can happen. (Also see my article about these things.)


Switched Outlets

Since replacing outlets correctly relies on making new connections, these may be done poorly or wrongly. More than one electrical item may fail to work as a result of a single mistake. An easy goof comes when replacing a plug-in receptacle, half of which has been controlled by a wall switch. 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. Kitchens wired in the 1960s may have a similar, easily missed complication. My article on this.
 

Outlet Hookups

Other problems for replacing outlets come from forgetting to reattach a wire or attaching it in the wrong place. 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. Video. Be aware also of two other matters to do with new receptacles. 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.
 

Switch Connections

Switches present difficulties as well. 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. 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. You may have to try up to three combinations before you get all things working right.
 

3-way Switch Confusion

The "three-way" switches that control lights from both ends of a room or hallway are easy to hook up incorrectly. This is absolutely the case if the new switches are not the three-way type (having three screw terminals that are not green in color). But even the new three-way switches may have a different alignment of screws than the old. Hint: attach the two wires which come from the same cable as each other to the two screws that are the same color as each other. Consult my diagrams relating to Three-way switches.
 

Light Fixture Replacement

Even the replacing of light fixtures is not foolproof. Sometimes the wiring at a light box is passing the circuit through to various outlets in the area, so that care must be taken to connect everything back as it was. Also, an old light fixture may also be hiding a surprise. Upon taking it down, you may find the ceiling and wires crisp from years of heat generated by bulbs of too high wattage. An electrician is often needed to make a good repair in such cases.
 

Replacement Strategy

In everything I have said above, I am assuming power is off while things are replaced. However, because connection mistakes are so possible, have a strategy for checking your work as you proceed. For instance, do one room at a time, replacing outlets and other items, then restore power, checking that everything works right there and also in nearby rooms before going on to the next room. Otherwise, you will have much more work to recheck later, with possibly more than one goof to complicate the picture.
 

Service Upgrades

On the subject of upgrading electrical things in general, I have some words of advice about the electrical service upgrade, also known as an electrical service change or a panel change. The only clear cases of a service upgrade being necessary are where the existing one is damaged beyond repair or where greater circuit space or service capacity cannot be achieved in another way. Other reasons can sometimes amount to paranoia, and may be promoted by contractors who certainly have a vested interest in advising the upgrade. True, the beauty of a new panel can be a real estate selling point, but trouble with a circuit tripping from an overload will never be solved by a new panel as such. Many existing panels can be given additional circuits even when they appear to be full; this is because a full-size breaker can often be replaced with two mini-size breakers in the same space in the panel. Or a subpanel can be added and fed from spaces whose present circuits will be relocated to the subpanel.

Restoring undone connections

© 2006-2012 Larry Dimock

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