How to wire up 3 switches in a 3 gang box to operate 3 How to wire up 3 switches in a 3 gang box to operate 3 different lights? - Answered by a verified Home Improvement Expert How to wire up 3 switches in a 3 gang box to operate 3 different lights? Customer Question. Now after looking over this diagram you have any questions at all - please dont hesitate to ask. Have a great day. How to Wire Three Switches in a Gang Box | Hunker How to wire three switches in a gang box seems a bit daunting just looking at it. You have only one power supply wire and three different fixtures to be wired to that power supply. Tame the tentacles and provide the power that will allow each fixture to be operated by a dedicated switch.