A switching apparatus includes a base, a housing, a main switch for mechanically disconnecting a power supply circuit and an interlock switch for electrically disconnecting the power supply circuit. The device comprises a canister, control circuitry disposed within the canister, and a lead assembly extending from the canister. A plurality of DR RCE are connected to phases of the distribution grid downstream of a corresponding substation transformer. The optical guide guides a light beam to the light emitting area in one of n equally divided areas of a ring-like opposing area which opposes the light receiving area.