I need to wire a single 120v outlet from the 240v volt wire I use on my compressor. Im installing a 120v electric automatic drain valve on my large shop air compressor. The compressor is wired up with SJ00W 10-AWG, 4-wire power cable (red,green,black white wires). and is rated at 240v @ 15-amp(compressor not wire). The drain valve uses a normal house hold current wiring config. (black,white and open copper)The 240v power supply is the only supply I have near by, (two of them actually) Or I would just wire the automatic valve off an outlet and call it a day. So How do I wire a 120v 3-wire set up from the 240v 4-wire supply? Thanks
If you have 10 AWG wire then you probably have a 30 amp breaker, correct? If so, you can't wire a standard 110v outlet on that large of a breaker. Duplex outlets are only rated for 20 amps. 30 amps and you're into range receptacles. You would probably need to install a sub-panel so you can switch down to a smaller wire size/breaker for the outlet. You could run the red, white and green into the sub-panel as the power source and then install a 15 or 20 amp breaker using 14 or 20 AWG wire to the receptacle respectively.
While it is not code, and I wouldn't advertise that you're doing it, you can quite easily take standard 12-2 romex, hook black to black, white to white and bare copper to the green, then install a 20 amp GFCI receptacle on the end of the 12-2 to run your drain valve.
Hud is correct. To accomplish this you would need to install a 30 amp subpanel with a 4 to 6 circuit configuration with a two pole breaker for feeding the compressor with # 10 wire and a one-pole 15 or 20 amp breaker with smaller wire (14 or 12 gauge respectively and the appropriate rated 120 volt outlet on that branch circuit). If you have regular 120 volt outlets somewhere nearby (as I think you are saying in your second to last sentence) I would go that route instead.
I swear these people on here are crazy sometimes. People he was never asking how to wire e recepticale. He is asking how to take a four wire 240vac connection to a 3 wire 120vac connection. He is wiring it to a auto drain valve that has a termination box on the side of it or a pecker head as we used to call it. Here is how to do it. Go to your breaker panel determine wick breaker is feeding the cable/wire your wanting to use. Once you have done this remove the breaker panel cover. Then remove the wires from the breaker. These should be the red and black wires. Now remove the two pole breaker and replace it with two single pole breakers rated at 20 amps. Using black electrical tape, tape the end of the red wire up and secure it inside the breaker panel so that it is out of the way. Now land the black wire to one of the breakers you just installed. The second breaker will not have anything wired to it, it is a spare to be used later but must be installed to cover the hole left by the two pole breaker. Label you panel to indicate the auto drain valve and the spare breaker you have just installed. Now at the auto drain valve the black will be the hot/L1 white is neutral/L2 and the green is ground. The red can be taped up and secured out of the way or cut back and taped up if you don't think you will need it in the future.
