# 240V Electric Heater install - 3 wire vs. 4 wire?



## jerryh3 (Dec 10, 2007)

Does the heater draw 40 amps, or does it require 40A protection? Can you post the model number. You are most likely correct. It is a three wire connection(hot, hot, ground). The ground will be a reduced size(most likely 10AWG)


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## dhgarage (Oct 11, 2008)

*heater details*

Ouellet Model# OASU10000T Specs show: Volts=240; Amps=41.67; Watts=10,000; BTU=34,120. For wire I'm thinking of using 8/8/10 gage (hot/hot/ground) unless 6/6/10 is recommended.


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## hpp58 (Feb 28, 2008)

6/6/10


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## joed (Mar 13, 2005)

The unit draws 41 amps. You need a 60 amp breaker. #6 wire required.


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## ssscamaro (Dec 6, 2008)

I just purcahsed same heater and came on here looking for help. i plan on pulling wire from my main panel to my attached garage. it will take about 90 feet of cable for this. For that reason i think i will do a 100 amp lug panel in garage with a couple extra future circuit capacities. i have not pulled cover off my heater but is this correct that it will only have 2 hots and a ground?? No neutral?
I am thinking 2/2/2/4 aluminum for run to lug box then 6 awg for panel to heater 60 amp breaker.
i will have electricain make final connection but because of complexity of cable pull trying to save some $$.
Most of the equipment i have serviced installed in past ( vacuum sytems and air compressors for denatl offices) used 2 hots neutral and ground. lack of neutral seems odd but i can understand why maybe its not used.
Can someone clarify for me? Also does the 2/2/2/4 aluminum sound like good choice?
Ryan


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## Plumbvoltage (Dec 2, 2008)

ssscamaro;197351lack of neutral seems odd but i can understand why maybe its not used.
Can someone clarify for me? Also does the 2/2/2/4 aluminum sound like good choice?
Ryan[/quote said:



> I believe the the leg that is out of phase is used as the neutral.
> 
> I had an addition done a couple years ago and they used the 2/2/2/4 alum. to feed a sub panel with a 100 amp breaker in the main.


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## handyman78 (Dec 29, 2007)

ssscamaro said:


> lack of neutral seems odd but i can understand why maybe its not used. Can someone clarify for me?


Neutral is only needed in this situation if there were a need for 120v in an appliance such as with an electric range which has both 120v and 240v loads. For a straight 240v item, no neutral is necessary and would not likely have a connection point. You do need the ground though.


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