A method is described for supporting a bundle of cables in a well or in a length of coiled tubing deployed in a vertical or deviated well during a process for assembly of a well heater which includes steps of injecting the cables from respective spools into the coiled tubing. The method includes the steps of: attaching an open-ended cable support adapter to the up-hole end of the coiled tubing, attaching a cable bundle clamp to the bundle of cables above the cable support adapter; cutting the cables from their respective spools above the cable bundle clamp; clamping a wedging tube carrier to the cable bundle above the cable bundle clamp; raising the cable bundle; removing the cable bundle clamp from the cable bundle; lowering the cables to insert the wedging tube into the adapter; and removing the wedging tube carrier from the bundle of cables.