Return to the Electrical Wiring Forum | Post a Follow-Up

 o
Multiple outlets on 220

Posted by dunk6666 (My Page) on
Thu, Apr 11, 13 at 13:38

I am working on plans for adding 220 outlets to my garage. I have a table saw, band saw and another tool that needs 220. If I know that they will never be powered on at the same time, can I install three outlets on the same circuit run? Like a standard run of 110 receptacles. It will be a 20 amp circuit.


Follow-Up Postings:

 o
RE: Multiple outlets on 220

Yes, multiple outlets are permitted on the same circuit. When the proper overcurrent device (circuit breaker is one example) is used, it will operate if the circuit is overloaded. I recommend that air compressors be on separate circuits since they often operate coincident with other loads.


 o
RE: Multiple outlets on 220

You my get away with it depending on the motor starting loads.

It is NOT a violation, but a separate article for motors (Article 430) allows their breaker size to be divorced from the conductor size to allow starting.

The wring needs to be 120% of the motors full load running current, from a HP table in the NEC (NOT the motor nameplate).
A typical inverse time breaker is then allowed to be larger than the wire size fr general purpose circuits by a couple hundred percent.

A motor that has a full load current of 15 amps would need wires rated at 18 amps, so #12.
The breaker might need to be 30 amps (or more) to allow for reliable motor starting.

The breaker is there only to protect against shorts in the wiring.

The motor has its own internal thermal protection that prevents it from overloading the wire.

The AHJ might have an issue with the breaker not matching ALL the motors that could use the circuit.

I mark the switch plates "MOTOR ONLY" just out of habit.
Maybe it will keep the next owner from just jamming any ole' 240 V load in there.


 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!


Return to the Electrical Wiring Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Please review our Rules of Play before posting.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.


Learn more about in-text links on this page here