how to wire (Tankless Water Heater)

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  #1  
Old 09-14-07, 05:53 PM
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Question how to wire (Tankless Water Heater)

Hi All
i purchase a tankless water heater
and it rated 220v 40 amp breaker
problem there only 2 white wire and a green wire witch is ground
it recommends #8/2 wire
my question is do i need a double pole breaker or a single 40 amp breaker

thanks
 
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  #2  
Old 09-14-07, 05:58 PM
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You always need a double pole breaker for 240 volt. A single pole breaker will only give you 120 volt
 
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Old 09-14-07, 07:20 PM
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2 pole breaker..

1 white to each of the breaker terminals , and the green to the ground buss.
 
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Old 09-14-07, 07:58 PM
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The white wires should be taped with black or red taped to identify them as hots. White is the color for neutrals and may cause confusion in the future.

Just to clear something up for you... Rollie mentioned 240 volts. That is the same thing as your required 220 volts. That voltage is also sometimes referred to as 230 volts. They're all the same. This is because the power company allows a certain degree of difference in voltage. I believe it's + or - 5%. Just like your outlets could be considered 110 volts, 115 volts, or 120 volts. It just depends on what you want to call it.
 
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Old 09-14-07, 09:16 PM
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Just out of curiosity: Why are manufacturers of devices such as the water heater mentioned here allowed to use white sheathing for hot wires?
 
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Old 09-14-07, 09:56 PM
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Originally Posted by ddr View Post
Just out of curiosity: Why are manufacturers of devices such as the water heater mentioned here allowed to use white sheathing for hot wires?
I helped a friend install one of these and I got the impression they were possibly "gray market" originally intended for European sales and the US seller not the manufacturer had added a NM pigtail for US sales. That might be the same here with the seller adding the white wires. Could be wrong. Wonder if the OP's heater was bought off Ebay as was my friends?
 
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Old 09-15-07, 07:14 AM
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Right on, Ray. These are gray market knock-offs of American and European devices manufactured in China or SE Asia that are sold on eBay sometimes under the original brand name.
 
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Old 09-15-07, 06:46 PM
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hi
Yes bought on ebay it from puorto rico
my problem here is the description

phase 1
volt 240
amp 40

if i put a double pole 40 amp braker will thst be a 2 phase?????????

or should i connect both white wire from the unit to the double pole 40 amp breaker
 
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Old 09-15-07, 06:52 PM
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Exclamation 1 phase or 2 phase

i bought a tankless water heater on ebay
it's a maury
the spec are

phase 1
volt 240
amps 40

there 2 wires white and a green one
green is ground

hsould i used a double pole 40 amp breaker and connect both white wire to the breaker???????

is that 1 phase or 2 phase
 
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Old 09-15-07, 07:35 PM
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Is this a duplicate? Someone just asked this....can't remember.


Residential wiring is only single phase.

Get a double pole 240 amp breaker.


Attach each white (grey) wires to each pole of the breaker and the green ground to the ground buss.

Mark the white wires with black/red electrical tape or similar.


Have you done a load calc to see if your current service has enough juice to supply 40 amps?
 
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Old 09-15-07, 07:38 PM
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Originally Posted by HotinOKC View Post
Is this a duplicate? Someone just asked this....can't remember.
No OKC, you are not going whacko.

http://forum.doityourself.com/showthread.php?t=317945.
it is actually the same poster.
 
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Old 09-15-07, 07:42 PM
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ahhhh! I'm on some good meds for my back issue, so I thought my mind was playing games on me.

Thanks Nap!
 
  #13  
Old 09-15-07, 07:55 PM
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sorry guys for the double post
getting old i guess
i have a 100 amps main breaker
buttttttttttttttttttt
this is a mobile home
the breaker at the meter box is 60 amps
i have gas stove
and a 20 amps ac

should this this be enough
or i need to replace the breaker at the meter with a 100 amps
run #2/3 from the meter to the mobile home 100 amps service panel
 
  #14  
Old 09-15-07, 08:57 PM
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The power in your house is single phase. Period. It is 240 volts single phase. 120 volts is obtained because of the neutral that is available.

Install a 240 volt 40 amp breaker.
 
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Old 09-15-07, 09:26 PM
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"this is a mobile home
the breaker at the meter box is 60 amps
i have gas stove
and a 20 amps ac

should this this be enough
or i need to replace the breaker at the meter with a 100 amps
run #2/3 from the meter to the mobile home 100 amps service panel"


Form the tone of your posts and questions may I VERY STRONGLY suggest you get a qualified electrician out there to do this job. I know we will all feel better that way.
 
  #16  
Old 09-16-07, 12:05 PM
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Yes a 100 amp main breaker will be necessary. I would reccomend going with 3wire #1 AL w/ground, or 3wire #3 CU w/ground for your feeders. There is a code exception that'd allow #2 AL or # 4 CU, but it may not apply to your local jurisdiction. Plus I've heard rumors of a change to this code. Go one size up and you're safe. Also, if you go with AL wires, make sure that the lugs are AL rated. If not, you have to use NO-OX (an electrical antioxidation compound).

Remember electricity can and DOES kill, so like speedy said, hiring an electrician may not be a bad idea.
 
  #17  
Old 09-16-07, 01:17 PM
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Just a quick clarification:

"Also, if you go with AL wires, make sure that the lugs are AL rated. If not, you have to use NO-OX (an electrical antioxidation compound)."

With AL wire the lugs MUST be AL or CO/ALR rated, whether do-ox is used or not.
 
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