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Discussion Starter · #1 ·
I am replacing an old air conditioner unit that had a NEMA 10-30P 30 Amp 250 volt receptacle with one that requires a LCDI NEMA 6-15P receptacle. The air conditioner is listed as 15 Amp 230 volt. The new 20 Amp 208 volt receptacle has two brass screws and a ground. The old receptacle is attached to black, white and red wires that run back to two separate 15 amp breakers in the box. How does the new receptacle get wired?
 

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I am replacing an old air conditioner unit that had a NEMA 10-30P 30 Amp 250 volt receptacle with one that requires a LCDI NEMA 6-15P receptacle. The air conditioner is listed as 15 Amp 230 volt. The new 20 Amp 208 volt receptacle has two brass screws and a ground. The old receptacle is attached to black, white and red wires that run back to two separate 15 amp breakers in the box. How does the new receptacle get wired?
You do not need the white for this 230 volt circuit. Do you have a bare ground or a green ground?

Use the black and red on the two brass receptacle terminals. Connect the ground to the ground terminal on the receptacle. Replace the 15 amp single breakers with a 15 amp two pole beaker. Put a wire nut on the white wire and tuck it in at the receptacle box and also at the panel.
You should have minimum #14 wire for the previous 15 amp receptacle. You must check this and see. Number 14 wire is good for 15 amps. The original receptacle was rated for 30 amp and I am not sure why it was used on a 15 amp circuit. The 30 amp circuit is more believable so you need to be sure what wire size you have.
So you will use the same cable and not use the white as long as it is at least #14 wire on a 15 amp breaker. Larger wire is just fine and most likely it will be larger than number 14.
You forgot the most important thing WIRE SIZE!

However. Where is the 208 designation coming from. Its not from NEMA. Both receptacles and plugs (new and old) are rated for 125 and 250 volts.
208 is only derived from a three phase system and I doubt you have three phase in your house if you live in the US.
 

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208 is only derived from a three phase system and I doubt you have three phase in your house if you live in the US.
It can if OP have very large service or live in the condo one of the two it may have pretty good chance he may got the triphase supply in there.

For the rest of details J.V. pretty much sum it up and make sure you double check the conductor size that is the main issue.

Merci.
Marc
 
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Discussion Starter · #4 · (Edited)
Upon further review, it is a 30 Amp two pole breaker and not two single 15 Amp breakers. The wire is #10 gauge. The 208 was one of numbers on the new receptacle box bought from Lowe's. We live in the US and there is no three phase in the house.

The voltage testor lit up at 110 with the red and black, red and white. It lit up at 220 with the black and white. Air conditioner unit fan up and running strong with red wire capped and black and white hooked up to brass terminals and ground terminal grounded to box. However, after three minutes, when the condensor kicks on the breaker trips.
 
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