3 Way Sockets Vs. 3 Terminal Sockets

Lamp sockets come in a variety of styles, colors, finishes, materials, and flavors. Note: Don't check the flavor of your socket while the lamp is plugged in! There are seriously a lot of things to choose from, but did you know there are also different socket interiors? The socket interiors sit inside the socket shell and come in keyless, push-thru, pull chain, and turn knob. Maybe the most complicated socket interiors are the 3 way and 3 terminal interiors. Begs the question....

What's the difference between 3 Way and 3 Terminal Sockets? 

3 Way Sockets

3 Way sockets have two contacts inside the socket and are made to burn 3 way bulbs. If you look at the bottom of the 3 way bulb there are two contact points on the bulb to match the contacts in the socket. 3 way bulbs have two filaments inside the glass. The 3 way socket allows the filaments to burn independently or in tandem.

3 Way Socket Ineriors

3 Way sockets will burn a standard bulb, but there will be an extra rotation from on to off. 3 way sockets are turn knob or pull chain sockets; they will never be keyless or push-thru. Mogul sockets are also 3 way, but require a mogul bulb.

3 Terminal Sockets

3 Terminal sockets are often confused with 3 way sockets but work completely different. They are designed to run an additional circuit; mostly used for another keyless socket. They are commonly found in 3 tier lamps or Gone-With-The_Wind style lamps. 3 terminal sockets have only one contact with the bulb.

3 Way Socket and 3 Terminal Socket Comparison

 The 3 terminal socket has 3 screws on the bottom for the wires to connect to the different bulbs. The broad headed screw connects the two smooth wires from the plug wire and the other socket. The brass screw connects to the smooth plug wire and the black screw connects to the smooth wire going to the other socket.

Wiring a 3 Terminal Socket Interior

Unlike the 3 way, a 3 terminal could be a turn knob socket or be keyless socket with a 2 circuit switch. Here are some examples of the type of lamps requiring a 3 terminal socket:

If you are repairing a lamp and come across one of these types of sockets, you have just entered the next level of repair. Congratulations!

Small Wooden Mouse Lamp

A customer brought in this lamp base the other day and wanted to complete it to a small table lamp. This unique lamp base is a Robert Thompson's Mouseman solid oak table lamp. The lamp had a threaded brass nipple on top of the lamp. The lamp parts needed to complete this lamp include: brass neck, harp base, solid brass socket, lamp cord, and a locking washer. This customer wanted all polished brass items on the lamp.

First thing is to thread the lamp cord through the lamp body. Twisting the stripped wires help the cord get through the lamp without snagging in the lamp body.

The thread on this lamp base is a 1/4IP (about a 1/2 inch). The lamp harp and the socket base connect to a 1/8IP (about 3/8 inch). Using a brass neck we convert the thread from the 1/4IP to the 1/8IP and get the socket off the lamp base: Win/Win.

Next the other lamp parts are added. The harp base goes on the neck. A locking washer goes on the harp base and the socket cap goes on the lock washer.

A UL knot is tied in the lamp cord and the cord is connected to the socket interior. The ribbed wire connects to the nickel screw and the smooth wire connects to the brass screw.

The cord slack is pulled back through the lamp body and the socket shell is snapped into the socket cap.

This lamp is ready for a bulb. The cord is plugged in and the lamp is turned on.

Perfect! This lamp looks really good and is made with great lamp parts. Total Cost < $20 Total Time < 30 minutes

Floor Lamp Cluster Rewired With Fat Boy Sockets

This patient came in the other day and needed some work. It has a cluster with two pull chain sockets. The sockets were not working at all. One can come loose from the socket cap. Upon further inspection, we notice the lamps plug is not polarized and the socket insulators are brittle. So the lamp parts we needed are two pull chain Fat Boy socket interiors, two Fat Boy socket insulators, some lead wire, wire nuts, and a snap on polarized plug.

First the cluster cap is removed and the wires are pulled out. These wires are old and really stiff. A pair of pliers is needed to pull the wires out of place.

The socket interiors can now be removed from from the cluster body.

The new sockets are wired with white and black leads. The new socket interiors have bright shiny pull chains and do not match anything else on this lamp. For a finished look, the old pull chains are removed from the old socket interiors and attached to the new socket interiors. The old socket was enclosed so a single screw removed and the socket opens up.

These sockets are Fat Boy sockets: they have a larger flared base near the socket cap. The insulators are a little tricky so the best thing is to push them in with the help of a table top of table edge.

Since the terminals on these interiors are on the bottom, it is important to inspect the insulators in the socket cap. These sockets are ready to be placed in the lamp.

With the lead wires in the cluster, the wires are clipped even. Wire nuts are used to connect the lead wires to the lamp cord. The black wires connect to the smooth wire and the white wires connect to the ribbed wires. The lead wires in the cluster are trimmed and the lamp wire is stripped. A UL knot is tied in the cord. The wires are stuffed into the cluster and the slack is pulled through the lamp body.

The cluster cap is placed back on the cluster.

The old lamp cord was not polarized so it is getting replaced with a polarized snap on plug. This cord was extra thick so we used a plug for an SPT-2 cord. The important thing is to line the cord up right in the plug: the smooth cord goes on the small prong and the ribbed cord goes on the wide prong.

This lamp is ready to be lit. Bulbs are added and the plug is plugged in.

Prefect. Total Cost <$ 25 Total Time < 40 minutes