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Neutral Vs. Ground in 240V Heater Wiring

bottom feeder

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Dec 10, 2012
Messages
331
Location
Utah
Hello! I discovered this forum while performing some online research for a 240V heater for my two car attached garage, and I'm very glad I did! This site is a great resource for help and ideas, and I thank you in advance for any help you may provide to my questions.

I've selected and purchased a Fahrenheat FUH54 garage heater unit for my 2 car attached garage. The specs and wiring information are available on their website:

http://www.marleymep.com/en/fahrenheat/pd-fuh-garage-heater/

My garage has an existing unused 240V welder circuit that I would like to use to power the heater. The Fahrenheat does not have an "off" switch, and it is not my intent to leave the heater on all the time, but rather to plug it in on those occasions when I need it. My plan is to wire it up with a male plug and plug it into the welder outlet rather than permanently hard wire it. That way I can still use the outlet for other things if necessary.

The NEMA 6-50 outlet in the wall has three wires running to it: red and black wires connect to the two "side" prongs, and white connects to the center (ground?) prong. There is also a bare, higher gauge (smaller diameter) wire that essentially doesn't run to anything - the electrician has looped it around one of the mounting screws that fasten the plug to the metal outlet box.

At the 200 Amp service panel, the red and black wires run to the terminals on a 240V breaker, and the white wire is connected to the neutral bus bar. The bare wire is connected to the ground bus bar. I should also note that this is a North American (Utah) location, single phase power, and the house was wired in 1996.

The heater wiring diagram shows where the two "hot" connections go, and the third connection is labeled "ground" and is essentially a screw that screws into the sheet metal of the heater.

My question is do I run the wire coming off the center prong of the plug (which is connected to neutral in the service panel) to the ground connection on the heater? Or do I somehow need to get that bare ground wire from the outlet to the heater (presumably by re-wiring the plug or using a different outlet)? I realize there is a lot of misunderstanding out there regarding ground vs. neutral on 240V, and obviously I don't have it clear in my head either. Being used to wiring 120V circuits, I have a hard time wrapping my brain around connecting a neutral wire to a ground lug. Any explanation or advice would be welcome.
 
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dimarcelli

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Jan 3, 2013
Messages
45
The ground should have been wired to the plug ground terminal. You won't be using the neutral (white wire) in your heater setup, just two hots and ground.

Wire the ground up properly in the receptacle and you should be good. Neutral on a 240 circuit is used by some appliances with 120 volt objects, such as motors or clocks.
 

socapots

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Jan 3, 2011
Messages
544
Location
Canada
Should the receptacle still be grounded. As in he runs the bare copper to the plug and the box?
 
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G_P

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Jul 11, 2010
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7,135
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Central CT
Disconnect the white wire at the panel and box ends when you hook up the ground to the plug.

Sent from the toilet using charmin ultra
 

dimarcelli

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Joined
Jan 3, 2013
Messages
45
Yeah G_P is right. You won't use the white wire at all, cap it on both ends. I couldn't remember earlier what the heck a 6-50 looked like. It's been forever since i've messed with one. It's just two hots and a ground.
 

pattenp

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Jun 4, 2008
Messages
10,175
Location
Virginia - USA
You need to verify the wire gauge and breaker size used on that circuit. Allowed wire and breaker sizes are different for welder circuits than a circuit for a heater.
 
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