The typical circuit wire connections to the 240 volt water heater is black to black, the red wire of the water heater connects to the white wire which is colored with red or black electrical tape, and the ground wire is fastened and bonded to the ground screw of the water heater. Electric Water Heater Wiring - Ask the Electrician Is this answer helpful?Thanks!Give more feedbackThanks!How can it be improved?How can the answer be improved?Tell us how Electric Water Heater Wiring - The Spruce Water Heater Wiring. At the water heater, the black circuit wire connects to the black heater lead, and the white circuit wire connects to the white heater lead. The white circuit wire should be wrapped with black or red electrical tape near the connection at both ends of the circuit, to indicate that it is a "hot" wire, not a neutral wire. wiring an electric hot water heater - Handyman WIRE Jan 22, 2006KMThomas: The Black & White wires in your panel would normally be a 120-volt circuit. Not enough voltage for the 240-volt Hot Water Heater. The Circuit Breaker that you refer to in your third post is a 30-Amp DBL Breaker which normally is wired with one Black & one Red AWG No Copper Wires for the Hot Water Heater.