True, but the fewer splices the better. 99 percent of electrical problems are poor connections. Keeping those connections and terminations to a minimum will lessen the chances of failures. A non-existent splice can not fail. The installer must weigh the convenience of having a splice against the risk of the splice causing future problems.Rainer ( MGL ) says copper extensions are acceptable as long as the cold junctions ( solder joints ) are the same temp.