We had installed two receptacles for this deck on the house walls but the homeowners wanted a receptacle by the railing. Because of the construction of the post, we could not mount the receptacle inside it or fish the wire to the receptacle. We had to surface mount a weatherproof box and use conduit to get the wire to the receptacle. Normally, we would use PVC conduit for this but because the railings were made of stainless steel, we decided to use EMT conduit to match the railings. Of course, it is not a perfect match but without close inspection, the illusion is good.