We highly recommend the use of a sub-panel in tankless heater installation. Please get the advice and installation from a qualified electrician. The Sub-panel offered is a Siemens Sub-panel with the required breakers already chosen for the unit you are ordering. Please keep to code when wiring. Use the right gauge wire. And, ask your electrician to mark both ends of the wire being drawn through conduit with identification. Note that each element MUST have its own circuit breaker. And, that makes the sub-panel so useful. It is mounted right next to your tankless. Wires are easily attached to the breakers. The sub-panel is wired with two wires and a ground, all with the proper gauge, to the appropriate two pole breaker in the main panel.
