What are The Ways To Wire Receptacles?
There are three ways to wire a receptacle if there are two wires to connect to it. There is the preferred way,an acceptable way and one of which is not preferred or recommended. The preferred method is to connect the wires and add a pigtail connection that attaches to the receptacle. Another possible way is to connect the wires on the two terminal screws provided by the manufacturer. And of course, the method that makes me cringe, back-wiring receptacles, by inserting the wires into the back of the receptacle in holes that sport small tension strips that contact with the stripped wire, making the connection point. So here's a look at the acceptable, the best, and the don't try this at home methods.
Feeding Through The Receptacles
Feeding through a receptacle is a common practice and I've seen it throughout my many years of being an electrician. Although it may be easier to some people and the electrical box may be less crowded, there are disadvantages to this practice. As you may know, with two wires in a box, one is the incoming wire (line) and one is the outgoing wire (load) that feeds the following receptacle. A receptacle comes equipped with two hot connection terminals, two neutral connection terminals, and a ground connection terminal. You can place one of the black wires under one of the brass screws and the other black wire under the other brass screw. The white wires are placed under the silver (neutral) screws. That leaves us with the two ground wires. These need to be twisted together and have two pigtail wires added to them. These ground pigtail wires will attach, one to the box and one to the receptacles ground screw terminal.
It has been determined that receptacles themselves have a certain resistance about them. This makes a case for voltage drop in an outlet. Having many receptacles wired in a circuit this way will reduce energy efficiency and potentially increase your monthly electric bill. Although each recptacle's voltage drop may be small, a combination of many will add up quickly.
One downfall to feeding through a receptacle is that the receptacle is in the middle of the circuit and any trouble in the wiring or receptacle spells trouble for receptacles connected downstream from it. The potential problem lies with the receptacles themselves and loose connections. A loose wire under one of these receptacle terminal screws could cause you to loose the downstream circuit receptacles as well.
Another thought is receptacle repair or replacement. If you have to take this receptacle out of the circuit, you interrupt the remaining downstrean receptacles. The wires must be reconnected to another receptacle before the circuit downstream can function again, leaving part of the house without power. This problem can all be eliminated by stripping the wire,twisting like wires together, and adding pigtail connections.
Pigtail Receptacle Connections
The best way to connect receptacles is to strip the wires, twist the same colored wires together, and make a pigtail. These pigtail connections are secured with wire nuts and the single pigtail wire is then connected to the receptacle terminal screw. This allows the circuit to continue to flow, enen if the wires are removed from the receptacle or if the receptacle is removed from the center of the circuit.
Back-wiring Receptacle Connections
Back-wiring receptacles is the simple man's way out. It just involves stripping the wires and pushing them into holes in the back of the outlet on the appropriate side of the receptacle, whether it be the hot or neutral connections that you're making. These wires slide against a small strip of copper located within the receptacle housing that bends slightly and holds tension against the wire to make the connectiona dn to hold the wire from coming out.
The downfall is that the wire can still rotate and is theoretically still a loose connection within the receptacle itself. If the connection tension isn't tight, flickering or arcing can take place and the wires could come out of the receptacle all together. For these reasons, electricians, local electrical codes, and the National Electrical Code often discourage and even disallow such connections.
There is an exception to the rule for back-wiring, if you call it true back-wiring that is. On some receptacles and switches alike, there are holes or slot where the wires can be inserted instead of wrapping the wires around the screws. In this case, the clamp holds the wire in place on the outside and the internal clamp tightens against the inside of the wire when the terminal screw is tightened. This makes for a tight and secure connection. In this case, this is my favorite receptacle connection for ease and quality connection.