Lamp Switch Wiring Diagrams
This page contains wiring diagrams for four different types of lamps. Included is a diagram for a two-circuit lamp switch to control a standard incandescent bulb on top of the lamp and a smaller, low wattage bulb in the base. Also include are diagrams for a standard one setting lamp, a three way lamp and an antique floor lamp with 4 light bulbs.
Finding Lamp Cord Polarity
Lamp cords are usually one color, making the standard black-hot, white-neutral guidelines useless for determining polarity. Other methods are therefore used to determine the polarity on a lamp cord. Check the insulation on the cord wires closely and you will find either a textured bead or a thin colored line running along one wire, this is the neutral. The plain wire is the hot. If the cord isn't marked with a bead then the strands of wire will be different colors. In these cases the silver wire is the neutral and the brass colored wire is the hot. The plug on the lamp cord holds another clue to polarity with the wide prong being the neutral and the narrow one the hot. Older lamp cord will have prongs that are the same size. This is because polarity was not observed on electric lamps until the development of grounded circuits.
It is the responsibility of the user of this information to know and understand the NEC (National Electrical Code) as it applies to them, as well as any local regulations or laws that may pertain. While many jurisdictions do adopt the standards of the NEC, some may have requirements in addition to, or exemptions from those standards. We cannot assume responsibility for personal injury or property damage as a result of using the information provided here.
The information on this page is intended to aid in electrical wiring projects that become necessary when doing DIY home improvements and repairs. Some of the diagrams here are for older circuits that may not adhere to the latest code updates. When running a new circuit be sure to use the latest approved wiring arrangements.
In the diagrams on this website the brass colored terminals on the devices represent the hot side of the circuit and the silver colored terminals represent the neutral side. Green is used to denote ground wires and terminals. Not all outlet boxes or older devices will have a grounding terminal. When running new wiring the ground wires should be spliced with a short piece of wire to connect to each device that has a grounding terminal, and to any grounding terminals in the outlet boxes. Also be aware that the white wire may be use to carry current in some household circuits, in these cases it should be marked with black electrical tape to indicate it is hot.
Wiring a 2 Way Lamp Switch
This diagram illustrates the wiring for a bedside lamp with two sockets. The top socket A, holds a standard incandescent bulb. The second socket B, typically holds a small, low-wattage bulb similar to a night light bulb. The switch allows for energizing the top bulb only, the night light only, both bulbs at once or for turning both bulbs off. This type of switch will be referred to as a 2 circuit lamp switch when shopping at home stores. Don't mistake this for a three way switch (pictured below), the two do not function in the same way.
Wiring a 3 Way Lamp Switch
Above is a wiring diagram for a standard, 3-way lamp switch. This socket is used with a three way bulb containing 2 separate elements that are energized separately and then together as the switch knob is turned, for varying degrees of light. These sockets have two terminals, one for the hot wire and one for the neutral. A third contact may be present but is not used for this circuit.
Wiring a Lamp Switch
This diagram illustrates wiring for a standard, one setting lamp. This socket has two terminals, the brass for hot and the silver for the neutral wire.
Wiring a Floor Lamp Switch
This is a wiring diagram for an antique floor lamp with 4 bulbs, one main bulb and 3 peripheral, and usually smaller bulbs. The main bulb threads into a standard socket with an integrated switch and the three peripheral bulbs are wired to a single switch. The secondary switch may have wires colored black, blue and red or, if it's an old switch, other colors or texturing may be used to distinguish them.
With this lamp, bulb A can be turned off and on independently and switch B can turn on bulb 1 alone, bulbs 2 and 3 together with bulb 1 off, bulbs 1, 2 and 3 all on at the same time or all three off.