What kind of a fitting will connect a lantern to a cast iron lamp post that has an inside diameter of 3.5 inches but has a lip at the top of the post?

Answer 1

The 3 1/2 is a frequently used size but the "lip" at the top is a bit unusual. If this is not a decorative or antique pole you may decide to remove the "lip." You can use an angle grinder or if you have a larger pipe cutter remove the top 1/2" or so. Note:Make sure prior to cutting, tuck the existing electrical connections out of the way. While you are modifying the pole consider adding a Photosensitive switch. The wiring is simple and only a small hole need be drilled to install.