A.Rex Cauldwell, a master electrician in Rocky Mount, Va., responds: The answer depends in part on the location of the new sconce. If the power cable feeds the fixture closest to the switch, you simply wire the most distant sconce into the first sconce and treat both as a single fixture (see illustration).
But if the power cable goes to the most distant light first, a three-conductor cable between the two lights is required to connect the second light's neutral conductor back to the first light's neutral conductor (in other words, the lights have to be wired in parallel). Without this three-conductor cable, the circuit won't function properly,...
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