Hi All,

I need to install a small tankless water heater (made for under the lavatory sink) for the sink in my bathroom. The specs on the water heater are: 120 Volts, 2.4kW, 20 Amps, wire size: 10AWG. My question is this... The existing bathroom outlet that I want to splice into to add this water heater on has a 15Amp breaker. Can I add a 20 amp receptacle using the same house wiring that is in place (the home was built in Palm Beach county, Florida in 1991) and I think it is either 12 or 14 gauge. To make this a 20A circuit, do I simply need to change the 15A breaker to a 20A breaker? The only device that will need the 20A is this new water heater, do I need to change ALL the receptacles on this breaker to 20amp receptacles? All advice will be helpful.

Sorry but no short cuts here, you will need a new 30 amp circuit, complete with a 30 amp single pole circuit breaker , #10-2 cable, and a 30 amp 125 volt straight blade NEMA 5-30R outlet, and large outlet cover.

The branch circuit rating needs to be 125% of the running load, and that is 25 amps and exceeds the rating of #12 wire.

You can make up a #10-3 cord with the NEMA 5-30P plug, this will serve as the service disconnect.

This heater pulls 20 amps, number 12 wire is good to 20 amps number 14 wire is only good for 15 amps, they recommend number 10 wire and since it is right on the top edge of a 20 amp breaker , I would suggest a 30 amp breaker because it would be less likely to cause breaker tripping problems. The 10 gage wire would be properly sized for a 30 amp breaker, this heater should be on a breaker by itself.