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Tankless Hotwater heater #202677 08/21/11 01:59 PM
Joined: May 2003
Posts: 1,154
dougwells Offline OP
Member
I have an inquiry about installing a circuit for this Item.
Will this need a sub panel and am a bit rusty about the feeder size for the a sub panel.
Has anyone installed on of these thanks.
This will be a renovation


http://www.e-tankless.com/stiebel-eltron-tempra-29-tankless-water-heater.php

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Re: Tankless Hotwater heater [Re: dougwells] #202678 08/21/11 09:54 PM
Joined: Jun 2004
Posts: 1,273
T
Tesla Offline
Member
"3 x 50 AMP breakers (depends on local codes)"

Each breaker at 240 VAC

"Minimum 3 x #8 AWG Copper (depends on local codes)"

So you'll need at least #8 -- but more likely #6 conductors.

(I'm assuming that you'll be dealing with a 60 degree panel board and or are using Romex. Otherwise, you'd be able to use #8.)

-----

I've never installed such a beast.

Instead I've installed insta-hots 30A @ 208 or 277...

You'll have to deal with line-of-sight disconnecting means -- which normally is addressed by a sub-panel rated 150 Amps @240VAC.

You can pipe and wire the feeder -- or use MC -- they make it big, BTW.

MC is available all the way up to 705 kCMIL. (!)


Tesla
Re: Tankless Hotwater heater [Re: dougwells] #202679 08/21/11 10:54 PM
Joined: Jul 2005
Posts: 183
J
jay8 Offline
Member
I am a little suprised at the electrical layout. The manufacturer is suggesting three breakers to a single control panel. How do you effectively isolate the unit for service, normally there is a single point of isolation on the control panel such as a service switch on the front of it.

Also, from the drawing (page 13) it looks like the exposed L1/L2 terminals are right next to the inlet and outlets ports for the water piping. The drawings show wires running right past the mechanical piping within the control panel. Unusual to say the least that there seems to be no barrier between the sections.


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