I am in the process of installing an outdoor natural gas tankless water heater. The issue I'm running into is clearances around the heater. There's a small spot on the back wall of the house where I'd like it installed.
The installation instructions require its exhaust vent to be located at least 12" away from an open window, but in order to meet this requirement I would need to mount it right next to my main electrical service panel (and electric meter).
The only code requirements I've found regarding clearances around an electrical panel are allowing at least a 30" working space (side to side). From what I understand, the panel can be located anywhere within that 30" boundary, so if this is the case I believe I can mount the heater pretty much right next to it as long as there's enough clearance on the opposite side to get me to that 30" width.
I've attached a graphic that shows the measurements on the house and a diagram that gives an example of how to comply with the electrical code: