Splicing is permissible on all of the following conduit bodies except?

Splicing is generally not permissible on pulling elbows because these conduit bodies are specifically designed to facilitate the pulling of wires through a conduit system. The shape and function of pulling elbows, which allow for changes in direction while minimizing cable stress and providing adequate space for wire pulling, do not support the intended purpose of a splice. Splicing in a pulling elbow could lead to potential issues such as obstruction of the pulling process, increased strain on the wires, and possibly violating electrical code regulations that dictate safe practices for electrical installations.

The other types of conduit bodies listed, such as couplings, skeleton type bodies, and junction boxes, are explicitly designed to accommodate splices or connections between wires or sections of conduit. These components provide adequate space, accessibility, and are constructed to support the electrical connections, adhering to safety standards and practices.