Tankless water heater wiring requirements..?

[Tim Fitzgerald]

Anyone that has wired one of these pls give me a rough idea of requirements as I am considering buying one...From what I have read, these things draw some incredible watts..IE 18,000 when in use

From what I have seen, it calls for 6ga wire and two 50 amp breakers. I am assuming the breakers would have to be tied together to get the required 75 amps...?

I threw this up in the main forum cuz its either this or a small tank which I guess i could run instead but space is kind of a factor.....IDK...?

It wont hardly be used as it will support a shower and sink in a small bathroom inside of 14x30 room within shop. One of those deals where the mother in in law may use shower onece a year when I kick her out of my main house...

 

[Norcal]

The water heater is broken down into 2- 50A circuits, so you do not tie the 2 circuits together, run 1 large feed to a small sub panel & then install your 2,50A breakers to the WH. Why screw with a power hog water heater? Use a gas model because you better have large electric service to handle a electric, & if it's only going to be used occasionally a couple of propane bottles will take care of the gas supply.

 

[Charles (in GA)]

Two separate 240v feeds to the water heater. Thats two double pole 50 amp breakers. That's four hot wires, two from each DP breaker, plus ground. Don't know if the unit needs a neutral for the control circuits or not.

NEC does not allow circuits of greater than 60 amp, and 48 amp of draw, to supply water heaters, space heaters, boilers, etc. Thus, if more than 48 amp of draw is needed the manufacturer builds it to take two separate 240v circuits.

Charles

 

[PRH44]

At 10 cents a KWH you are looking at $1.80 an hour to heat. The less you use these devices the more they offset the cost of a standard water heater. However heavy use can be more costly than a 40 to 50 gallon tank heater that uses 50 cents an hour.

Unfortunately these days in most parts of the country that burn coal a good size portion of your monthly bill has nothing to do with your KW usage.