Multiple 220 Volt Outlets - Electrical - DIY Chatroom Home Improvement Forum

 DIY Chatroom Home Improvement Forum Multiple 220 volt outlets
 Register Blogs Articles Rewards Search Today's Posts Mark Forums Read

01-29-2009, 11:50 AM   #1
Newbie

Join Date: Jan 2009
Posts: 3
Rewards Points: 10

## Multiple 220 volt outlets

I apologize if this has already been answered -- I did look before posting.
I need to add wiring in my garage for both a table saw and a dust collector system. Both use 220 volt, single phase motors. Each motor's plate says 15 amps.

Is 15 amps the maximum, starting or continuous amps? If 15 amps is the starting load it's unlikely that both items would be starting at exactly the same time? I need to run 50 feet from the main breaker box to the outlets. I already have 75 feet of 10/3 cable. I believe this cable would handle a maximum of 30 amps.

Keeping in mind that I already have 75 feet of 10/3:
Should I run a single 10/3 and wire the two outlet boxes in series, run a seperate 10/3 to each outlet box, or a single larger cable in series to the two outlet boxes, or is there a more preferred way to do this?

Also, what size breakers should I use?

01-29-2009, 11:55 AM   #2
DIYer

Join Date: Oct 2008
Location: Virginia
Posts: 910
Rewards Points: 500

The table saw will draw more when you are actually sawing. The dust collector will draw more when it's getting full.

The nameplate amps are closer to the maximum than the continuous load. It should be fine to run both of them on a single 30 amp circuit. 10 gauge wire gets 30 amp breaker.

When you say "wire in series", I guess you don't mean literally in series, outlets are always in parallel.

 01-29-2009, 12:07 PM #3 Newbie   Join Date: Jan 2009 Posts: 3 Rewards Points: 10 Thanks for the quick reply. Yeah, I meant to say parallel. By 30 amp breaker, does that mean two 30 amp breakers or two 15 amp breakers?

01-29-2009, 12:08 PM   #4
DIYer

Join Date: Oct 2008
Location: Virginia
Posts: 910
Rewards Points: 500

Quote:
 Originally Posted by Strider Thanks for the quick reply. Yeah, I meant to say parallel. By 30 amp breaker, does that mean two 30 amp breakers or two 15 amp breakers?
One double pole 30 amp breaker.

 01-29-2009, 05:03 PM #5 Member   Join Date: Oct 2007 Posts: 2,294 Rewards Points: 1,000 To utilized the 10/3 cable, I'd install a small sub panel in the workshop with two 15 amp 240 breakers for the equipment. You can use the 10/3 to the equipment but you want to somewhat protect the equipment with a 15 amp breaker. You dont wan't to install both pieces on a single 30 amp circuit.
01-30-2009, 12:12 AM   #6
DIYer

Join Date: Oct 2008
Location: Virginia
Posts: 910
Rewards Points: 500

Quote:
 Originally Posted by 220/221 You dont wan't to install both pieces on a single 30 amp circuit.
Why not? Breakers aren't designed to take the place of overloads. The motor can burn up almost as easily on a 15 amp breaker. If you have a fault that isn't going to magnetically trip a 30 amp breaker, it won't magnetically trip a 15 amp breaker either. So you are down to the thermal trip profiles, and the 15 amp just trips a few minutes sooner. Not soon enough to keep the motor from burning up in most cases.

 01-30-2009, 02:10 AM #7 UAW SKILLED TRADES     Join Date: Jan 2007 Location: Kansas Posts: 5,341 Rewards Points: 2,652 I don't see how you can suggest a 30 amp branch circuit for 230 volt power tools that are going to have cords and plugs rated either 15 or 20 amps (6-15's or 6-20's). The receptacles those tools will plug into must be rated 30 amps the minute you put that multi receptacle branch circuit on a 30 amp double. __________________ " One nice thing about the NEC articles ... you have lots of choices" Stubbie
01-30-2009, 03:31 AM   #8
Member

Join Date: Oct 2007
Posts: 2,294
Rewards Points: 1,000

Quote:
 Why not? Breakers aren't designed to take the place of overloads
Knock yourself out then. What I meant was, I wouldn't. Doesn't seem smart. Motor says 15 amps, I'd put it on a 15 amp circuit.

01-30-2009, 05:48 AM   #9
Electrician

Join Date: Aug 2007
Location: Connecticut, Litchfield
Posts: 2,015
Rewards Points: 1,000

Quote:
 Originally Posted by Gigs It should be fine to run both of them on a single 30 amp circuit. 10 gauge wire gets 30 amp breaker.
Its actually a code violation to do what you suggest. A 30 amp circuit gets a 30 amp receptacle...

 01-30-2009, 06:07 AM #10 Electrical Contractor   Join Date: Feb 2008 Location: Colonia, NJ Posts: 127 Rewards Points: 75 According to 430.24 the feed wires should be a #8 Need more name plate information to figure out the breaker size.
01-30-2009, 01:17 PM   #11
DIYer

Join Date: Oct 2008
Location: Virginia
Posts: 910
Rewards Points: 500

Quote:
 Originally Posted by chris75 Its actually a code violation to do what you suggest. A 30 amp circuit gets a 30 amp receptacle...
Thanks, I didn't think about the receptacle.

 01-30-2009, 01:52 PM #12 Newbie   Join Date: Jan 2009 Posts: 3 Rewards Points: 10 Thanks for the input. The users manual for the table saw says to use a 20 amp time lag fuse. The users manual for the dust collector says to use an appropriately rated circuit breaker (the motor plate says 14.7 amps). I suspect that what I need to do is: 1) Add a double 30 amp breaker to the main panel (I assume this breaker is really 15 amps per side)? 2) Run 10/3 cable from the main panel to a small sub panel. 3) Use a 20 amp breaker for the output to the table saw. 4) Use a 15 amp breaker for the output to the dust collector. What say you?
01-30-2009, 03:26 PM   #13
Electrician

Join Date: Aug 2007
Location: Connecticut, Litchfield
Posts: 2,015
Rewards Points: 1,000

Quote:
 Originally Posted by Strider Thanks for the input. The users manual for the table saw says to use a 20 amp time lag fuse. The users manual for the dust collector says to use an appropriately rated circuit breaker (the motor plate says 14.7 amps). I suspect that what I need to do is: 1) Add a double 30 amp breaker to the main panel (I assume this breaker is really 15 amps per side)? 2) Run 10/3 cable from the main panel to a small sub panel. 3) Use a 20 amp breaker for the output to the table saw. 4) Use a 15 amp breaker for the output to the dust collector. What say you?
I say buy some 12-2 and be done with it.

 01-30-2009, 03:30 PM #14 " Euro " electrician     Join Date: Apr 2006 Location: WI & France { in France for now } Posts: 5,369 Rewards Points: 2,000 The other thing when you use the 12-2 NM or UF's cables make sure you remarked the white conductor with either tape or sharpie permenant marker. That way you know it is not wired for 120 volt set up. Merci,Marc
01-30-2009, 06:23 PM   #15
Member

Join Date: Nov 2007
Location: Nashua, NH, USA
Posts: 7,971
Rewards Points: 1,548

Quote:
 Originally Posted by Strider 1) Add a double 30 amp breaker to the main panel (I assume this breaker is really 15 amps per side)? ?
The double 30 amp breaker is 30 amps per side.

With 15/20 amp cord and plug equipment you don't have the problem of a 15 amp motor safeguarded only with a 30 amp breaker because the matching (15 or 20 amp) receptacle needs a breaker no more than 20 amps either at a subpanel or at the main panel. With cord and plug equipment you have to be conscious of not plugging both into receptacles served by the same 20 amp. subcircuit.

With cord and plug equipment, it is easy to overlook installing a 40 amp feed with 8 gauge wire in anticipation of connecting motorized equipment and sizing up the implications of the 125% load provisions of 420.34 of the NEC. Meanwhile not plugging both pieces of equipment into receptacles on the same side of the 30 amp. line would avoid random breaker trips.

__________________
The good conscientious technician or serviceperson will carry extra oils and lubricants in case the new pump did not come with oil or the oil was accidentally spilled, so the service call can be completed without an extra visit.

Last edited by AllanJ; 01-30-2009 at 06:53 PM.

 Thread Tools Display Modes Linear Mode

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is OffTrackbacks are Off Pingbacks are Off Refbacks are Off Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post border collie Electrical 19 04-12-2013 12:29 PM flyultralite Electrical 7 11-25-2008 01:09 PM SURFBUG Appliances 6 10-14-2008 09:41 PM joeyboy Electrical 7 08-27-2008 08:37 AM G19-Fanatic Electrical 17 08-28-2006 01:55 PM

Top of Page | View New Posts