Electrician Talk - Professional Electrical Contractors Forum
CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!
Go Back   Electrician Talk - Professional Electrical Contractors Forum > Electrical Trade Topics > Services and Service Equipment
Back-feeding breakers Back-feeding breakers
Register Electrical Photos FAQ Members List Social Groups Contractor Talk Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
Old 10-19-2009, 09:03 PM   #1
Tallman
 
Join Date: May 2009
Location: White Mountains of NH
Posts: 10
Default Back-feeding breakers
I have encountered a partially upgraded service. The old 60 A fusebox still serves as the main. The new sq. D QO box has a 70A breaker, back-fed and interlocked with a 30A generator breaker. My question is- do QO breakers merely act as disconnects when back-fed, or do they offer over-current protection?
bharbwyr is offline   Reply With Quote
Join Contractor Talk

Join the #1 Electrician Forum Today - It's Totally Free!

ElectricianTalk.com - Are you a Professional Electrical Contractor? If so we invite you to join our community and see what it has to offer. Our site is specifically designed for you and it's the leading place for electricians to meet online. No homeowners asking DIY questions. Just fellow tradesmen who enjoy talking about their business, their trade, and anything else that comes up. No matter what your specialty is you'll find that ElectricianTalk.com is a great community to join. Best of all it's totally free!

Join ElectricianTalk.com - Click Here JOIN FOR FREE

Warning: The topics covered on this site include activities in which there exists the potential for serious injury or death. ElectrcianTalk.com DOES NOT guarantee the accuracy or completeness of any information contained on this site. Always use proper safety precaution and reference reliable outside sources before attempting any construction or remodeling task!
Old 10-19-2009, 09:54 PM   #2
Senior Member
 
drsparky's Avatar
 
Join Date: Nov 2008
Location: Presque Isle, Maine
Posts: 1,579
Default
Current flow in either direction will make the breaker trip.
__________________
"Pay attention son, this is for your own good." - Foghorn Leghorn
drsparky is online now   Reply With Quote
Old 10-19-2009, 11:02 PM   #3
Rat Extraordinaire
 
480sparky's Avatar
 
Join Date: Sep 2007
Location: Iowa
Posts: 6,790
Default
It makes no difference which end a breaker is fed from. Current flowing one direction will be flowing the opposite in 1/120th of a second.
__________________
All responses based on the 2008 National Rat Code.
480sparky is online now   Reply With Quote
Old 10-20-2009, 01:58 AM   #4
zen
electrican
 
zen's Avatar
 
Join Date: Jun 2009
Location: tx
Posts: 122
Default
so why do some people feed a mlo panel from the main panel under a breaker and some feed from the main under a breaker to a breaker in the mlo panel
__________________
if i knew half as much as i thought i knew i might know something
zen is online now   Reply With Quote
Old 10-20-2009, 09:36 AM   #5
Rat Extraordinaire
 
480sparky's Avatar
 
Join Date: Sep 2007
Location: Iowa
Posts: 6,790
Default
Quote:
Originally Posted by zen View Post
so why do some people feed a mlo panel from the main panel under a breaker and some feed from the main under a breaker to a breaker in the mlo panel
Same reason some people wear boxers, others wear briefs.

Same reason some people drive vans, others drive pickups.

Same reason some people wear baseball caps, others don't.


If the other end of the feed has a properly-sized overcurrent device, you don't need one in the MLO panel.
__________________
All responses based on the 2008 National Rat Code.
480sparky is online now   Reply With Quote
Old 10-20-2009, 09:49 AM   #6
Senior Member
 
chenley's Avatar
 
Join Date: Feb 2007
Location: Kentucky
Posts: 431
Default
Quote:
Originally Posted by 480sparky View Post
Same reason some people wear boxers, others wear briefs.

Same reason some people drive vans, others drive pickups.

Same reason some people wear baseball caps, others don't.


If the other end of the feed has a properly-sized overcurrent device, you don't need one in the MLO panel.
That just reminded me of this from Joe Dirt:

Hey, how exactly is a rainbow made?

How exactly does the sun set?

How exactly does the posi-trac
rear end on a Plymouth work?

-It just does.
chenley is offline   Reply With Quote
Old 10-20-2009, 10:52 AM   #7
Tallman
 
Join Date: May 2009
Location: White Mountains of NH
Posts: 10
Default
I see that according to 408.36(D), I'm good to go as long as the backfed breaker is fastened in place, which, thanks to the generator interlock bracket, it is.
bharbwyr is offline   Reply With Quote
Old 10-20-2009, 10:27 PM   #8
Master Electrician
 
rewire's Avatar
 
Join Date: Mar 2009
Location: Eldon Missouri
Posts: 886
Default
Quote:
Originally Posted by bharbwyr View Post
I see that according to 408.36(D), I'm good to go as long as the backfed breaker is fastened in place, which, thanks to the generator interlock bracket, it is.
I don't think the interlock prevents removal of the breaker
rewire is online now   Reply With Quote
Reply

« Previous Thread | Next Thread »
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes
Linear Mode 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 Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Feeding underground in block walls Marshall175 General Electrical Discussion 18 07-24-2009 09:56 PM
Feeding a sub panel subelect General Electrical Discussion 5 05-08-2009 03:15 PM
12-2 feeding 12/3 subelect NEC Code Forum 4 11-09-2008 09:56 PM
Feeding switches bgec UK Electrical Forum 4 10-19-2008 11:13 AM
Question about back feeding Golden Arc General Electrical Discussion 44 07-29-2008 10:32 PM

Top of Page | View New Posts

All times are GMT -4. The time now is 09:39 PM.

Contact Us - Electrical Forum - Top

Electrician Talk © 2006 - 2009 The Building Network LLC

Search Engine Optimization by vBSEO 3.2.0