Disconnect for electric tankless water hester

[jlyrintzis]

I'm installing a Rheem Retex-27 27kw electric water heater. While it's not required by the code where I am, I'd like to have a disconnect switch for it. It requires 3 40A double-pole breakers with obviously 2 wires for 240V coming from each, so total 6 gauge 8 wires plus ground coming to the water heater. What kind of disconnect switch should I use? I did not find any switches that take multiple 240V circuits coming in.

 

[Twowaxhack]

No idea but it sounds like you’re about to spend some money.

I’d go to an electrical forum with this question.

 

[Mitchell-DIY-Guy]

I'm installing a Rheem Retex-27 27kw electric water heater. While it's not required by the code where I am, I'd like to have a disconnect switch for it. It requires 3 40A double-pole breakers with obviously 2 wires for 240V coming from each, so total 6 gauge 8 wires plus ground coming to the water heater. What kind of disconnect switch should I use? I did not find any switches that take multiple 240V circuits coming in.

To achieve your goal you’re going to need to switch or disconnect SIX hot legs. That’s most likely going to be 3 x 2-pole disconnects OR 2 x 3-poles disconnects. I have not heard or seen a six pole disconnect.

You may consider an electric sub-panel near the unit, and put the breakers there. Disconnects or safety switches for this amount of current is a lot of hardware and not cheap. I did add a single 30A disconnect to my dad’s new conventional tank water heater. It was a $16 part.

Consider consulting your local electrical inspector (they can be helpful for homeowners) for suggestions, or an electrical contractor to do the work.