Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Electrical

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 05-18-2009, 06:49 PM   #1
Member
 
Join Date: Feb 2009
Posts: 284
Share |
Default

What size breaker


someone just gave me an old welder a craftsman dual range 295 amp welder.... i only plan to use 3/32nd rods around 110 range...... I have a detached barn with a sub ran from house using a 40 amp breaker with 6 GA wire not sure why... All that the barn really uses is 4 lights, one sensor light on the outside, and a few receptacles fed by 2...20 amp breakers....... what size breaker would you recommend for this welder? what is safe. what is the max breaker size i can add ..... I do not know enough to and cannot google the answer...do i need to replace the 40 in the house?


Last edited by Ineedhelp2009; 05-18-2009 at 07:12 PM.
Ineedhelp2009 is offline   Reply With Quote
Old 05-18-2009, 07:37 PM   #2
Idiot Emeritus
 
Join Date: Mar 2008
Location: Fernley, Nevada (near Reno)
Posts: 1,583
Default

What size breaker


Usually welders like this are on a 50 amp circuit. The trip curve of a typical 50 amp breaker pretty closely matches the duty cycle of the welder.

I've seen plenty of them on 30s though. That's what a typical temporary power box on a construction job will have. A 30 will trip if you weld for a long time at a high current setting, or if you stick the rod for more than about 5 seconds.

Here's what the code has to say; (Article 630).

1) Wire size; for a welder like you have, the minimum wire size is the rated input current multiplied by the value given in the duty cycle table. (20%=.45, 30%=.55, 40&=.63, 50%=.71, 60%=.78.) Most buzz-boxes are 50 amps and a 20% duty cycle.

2) Breaker size. There's no minimum, but the maximum cannot be more than 200% of the rated current. If there's a cord and plug, the breaker size cannot be more than the rating of the receptacle. The breaker cannot exceed 200% of the wire size in any case.

This is one of the few times you can have a larger breaker than normally allowed, but only if the welder is hard-wired.

Rob

P.S. If I were you, I'd put it on a 30. That way, if it does trip, there's a good chance that the main at the house will stay on, and thus the lights will also stay on.


Last edited by micromind; 05-18-2009 at 07:40 PM.
micromind is offline   Reply With Quote
Old 05-18-2009, 07:52 PM   #3
Member
 
Join Date: Feb 2009
Posts: 284
Default

What size breaker


Quote:
Originally Posted by micromind View Post
Usually welders like this are on a 50 amp circuit. The trip curve of a typical 50 amp breaker pretty closely matches the duty cycle of the welder.

I've seen plenty of them on 30s though. That's what a typical temporary power box on a construction job will have. A 30 will trip if you weld for a long time at a high current setting, or if you stick the rod for more than about 5 seconds.

Here's what the code has to say; (Article 630).

1) Wire size; for a welder like you have, the minimum wire size is the rated input current multiplied by the value given in the duty cycle table. (20%=.45, 30%=.55, 40&=.63, 50%=.71, 60%=.78.) Most buzz-boxes are 50 amps and a 20% duty cycle.

2) Breaker size. There's no minimum, but the maximum cannot be more than 200% of the rated current. If there's a cord and plug, the breaker size cannot be more than the rating of the receptacle. The breaker cannot exceed 200% of the wire size in any case.

This is one of the few times you can have a larger breaker than normally allowed, but only if the welder is hard-wired.

Rob

P.S. If I were you, I'd put it on a 30. That way, if it does trip, there's a good chance that the main at the house will stay on, and thus the lights will also stay on.

Great thanks, THere is some 10-2 already ran to an outlet will just changed boxes and run a 30 amp breaker...
Ineedhelp2009 is offline   Reply With Quote
Old 05-19-2009, 08:53 AM   #4
Member
 
Join Date: Jul 2008
Location: Pennsylvania, USA
Posts: 272
Default

What size breaker


Let's have the model number and we'll check for the manual. Lots of good info in there if we can get it...including OEM recommended power setup.
__________________
Willis
williswires is offline   Reply With Quote
Old 05-19-2009, 06:43 PM   #5
Member
 
Join Date: Feb 2009
Posts: 284
Default

What size breaker


Quote:
Originally Posted by williswires View Post
Let's have the model number and we'll check for the manual. Lots of good info in there if we can get it...including OEM recommended power setup.
113-201392
THanks
Ineedhelp2009 is offline   Reply With Quote
Old 05-19-2009, 06:47 PM   #6
Member
 
Join Date: Feb 2009
Posts: 284
Default

What size breaker


Quote:
Originally Posted by Ineedhelp2009 View Post
113-201392
THanks
Resolved thanks for your help. I put a 60 amp breaker in the house and put a 40 in the barn. The wire already ran for the outlet was 10 ground and 8guage hots...... Welder works will see it it trips.

Last edited by Ineedhelp2009; 05-19-2009 at 08:04 PM.
Ineedhelp2009 is offline   Reply With Quote
Old 05-20-2009, 10:45 AM   #7
Member
 
Join Date: Jul 2008
Location: Pennsylvania, USA
Posts: 272
Default

What size breaker


Here is the manual for your welder, printed in 1980, in case you don't have it:

Click on 'VIEW MANUAL" in the lower half of the page.

http://www.managemyhome.com/mmh/owne...1392+CRAFTSMAN
__________________
Willis

Last edited by williswires; 05-20-2009 at 10:50 AM.
williswires is offline   Reply With Quote
Old 05-20-2009, 06:44 PM   #8
Member
 
Join Date: Feb 2009
Posts: 284
Default

What size breaker


Quote:
Originally Posted by williswires View Post
Here is the manual for your welder, printed in 1980, in case you don't have it:

Click on 'VIEW MANUAL" in the lower half of the page.

http://www.managemyhome.com/mmh/owne...1392+CRAFTSMAN

alot of help thank you

Ineedhelp2009 is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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 Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Sq D Trillaint Breaker problem jmreynol Electrical 3 04-28-2009 07:06 PM
wire & breaker size rcassidy Electrical 8 02-17-2009 08:37 PM
Wire size and breaker discrepancy Randell Tarin Electrical 22 04-10-2008 07:03 PM
Generator Safety Switch Help - Breaker Size? limey_swindon Electrical 3 01-09-2008 11:40 AM
Wire size and Breaker size for remodel ?? Skydmark1 Electrical 12 12-15-2007 05:00 PM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.