Electric Instant Hot water install.

[clemsonfor]

Ok so the time has come to finially get around to this project. I bought it awhile back on sale. Anyway I am putting it into a closet basically across the hall from my main panel. The Heater requires three (3) double pole 40amp breakers. The decision I am trying to make here is do I install a sub panel next to the heater in the closet and put the three double pole breakers there to feed the heater with short runs of wire or do I just put the breakers in the main panel and feed the three 8awg wire to the heater in the closet. I ha e the space in the main panel for the breakers so that is not an issue. If I install a sub, what size wire is it...2/0? What size breaker would I need to feed that sub. I know it's not a total addition thing just adding up breaker size, but what is the calculation to find out what's NEC and safe more importantly. And for a space issue if the space occupied by three 8/2 wires coming out of the main panel larger than the one wire needed to feed a sub panel?

As for the distance. I would think the wire run from the main panel to either the heater or sub panel would be no farther than say 30ft. Down into crawl or up into attic, over 9ft or so and back into the closet for the heater.

 

[RNeumann]

Assuming you are using copper THHN wire in conduit you would need #2 copper wire to feed the sub-panel. The breaker would need to be at least 120a and the “typical” size is 125a. Then the 3 40a breakers would need to be #10 wire. The size for the 40a breakers will change if you run romex.

The sub panel needs a separate ground and neutral so you would need to run 4 wires to it.

I laughed at the specs for these demand electric heaters when I saw them. Good luck! I assume the lights will dim or flicker when it goes off.

Don’t forget disconnects at the heater if the panel/sub panel isn’t within view of the heater.

 

[clemsonfor]

Your last comment is why I am leaning to the sub right next to the heater. I was thinking that per code sub panels, the neutral and ground were bonded.

As far as operation, my aunt has one, hers is for s small house but there on well water and it's COLD compared to my water even in winter and it must use quite a bit of power to warm water. I don't notice any light dimming at her house?

 

[woody]

This is interesting keep us posted, what brand and model did you get?

 

[kenmac]

@120-125 amps. that water heater is going to eat some money if you are in the shower for very long.
I have a tankless gas unit. It saves when they get in and out of the shower.
Problem is, they have continuous hot water making them stay in the shower longer.. LOL

 

[clemsonfor]

This is interesting keep us posted, what brand and model did you get?

I may regret it. But I saw many happy customers. It is an eco smart 27 model from Amazon. It was something like over $100 off with a lightning deal. I grabbed it. I don't remember the cost now. I have been so busy I have had it a year or more. You basically have no warranty if you DIY. Unless your a licensed electrician or plumber. You have to show it was installed by one of them to get the warranty. But for me to pay one of them would cost more than the unit it self cost so what do you do??

 

[clemsonfor]

@120-125 amps. that water heater is going to eat some money if you are in the shower for very long.
I have a tankless gas unit. It saves when they get in and out of the shower.
Problem is, they have continuous hot water making them stay in the shower longer.. LOL

I have heard the same thing.

My tank unit is over 25 years old so it needs to be replaced. We have no gas out here and I am not setting up propane and all that comes with that so electric bis the only option.

It also only kicks in elements as needed. If you only need one 40amp to run a shower that's all it does. It says in hot climates it can run 3 showers and a like half a sink. While I don't have three functioning showers I might do clothes or dishes in a shower. Or two showers. I also want to make sure there is extra capacity in the winter, but our water doesn't get that much colder then. Summer cold water is pretty dang hot out of my tap already.

But it cuts elements on as needed to keep up at the desired output temp.

 

[kenmac]

I installed a elec. tank W.H. for a customer last week. 55 gallon. It is a newer efficiency mod. he bought. More insulation ,etc,. 55 gallon

Good luck with the install..Let us know how it all works out

 

[Pabco]

Is this a clothes closet? In general, installing a load center in a clothes closet is a violation of the NEC (240-24(d). Also, be sure to comply with 110-26 (working clearances).

 

[CobyRupert]

Neutral and ground should NOT be bonded in sub-panel.
Neutral and ground should only be bonded in one location (usually main panel, sometimes an upstream disconnect switch)
If you bond neutral & ground at sub-panel, then neutral current has parallel path on ground conductor back to main panel. Ohm’s laws says this current through conductor’s resistance will raise a voltage on anything connected to the ground system, like outlet and switch boxes, etc..