20 amp 240 outlet

[Bartman6969]

I'm in an Older home that has a 20amp 240 outlet that was originally for a window AC unit. These outlets did not have a ground as far as my research has found. My question is, if i build my control box with a grounded 120 outlet to run the controls and for a ground, could I use this outlet for a 3500w heater element without issues?

 

[processhead]

Does the outlet have 3 conductors?
Odds are good that the center one is a ground.

 

[Bartman6969]

Does the outlet have 3 conductors?
Odds are good that the center one is a ground.

It is 3 conductor but from what I read on the NEMA 10-20 it is 2 hots and a neutral, originally installed for window AC units.

 

[jpsmithny]

If the cable is the armored type i.e. metallic covering then that was used as the "earth".
Current code calls for a separate conductor for ground.

 

[AnOldUR]

It is 3 conductor but from what I read on the NEMA 10-20 it is 2 hots and a neutral, originally installed for window AC units.

Can't tell without a picture, but pretty sure that's two hots and a ground (not a nuetral). Use it as is with one of these.

 

[Bartman6969]

It is just a smaller version of a 3 wire dryer outlet configuration. Where you would bond the ground and the neutral on the dryer and I believe they are bonded at the panel. How do you guys deal with grounding when using the dryer outlet

 

[jeffmeh]

For H-H-N, many use the 3-in, 4-out GFCI spa panel wiring. Not as good as having H-H-N-G, and not to code, but code is not relevant if you wire it as a pluggable (not part of your house wiring) device, and it gets you the GFCI which you really want for safety.

 

[Bartman6969]

For H-H-N, many use the 3-in, 4-out GFCI spa panel wiring. Not as good as having H-H-N-G, and not to code, but code is not relevant if you wire it as a pluggable (not part of your house wiring) device, and it gets you the GFCI which you really want for safety.

In that situation would you bond the Neutral and ground from the Spa panel to the plug into the wall like you would do when wiring the dryer to the 3 prong plug?

 

[kenglish427]

you can clear up the ground/neutral (grounding/grounded) conductor issue by looking at the wires, if its bare, its a grounding conductor.
you do not want to alter any "permanently installed" device, What the previous post was recommending, I think, is for you to make a jumper in your control panel, or in the plug end on your cord if it is serviceable, and tie the grounding, and grounded conductors together. It is not the best practice to allow your Neutral current to flow on an uninsulated conductor, but I know more than a few stoves that operate that way. (mine included)
Hope this clears it up.