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#96610 - 12/12/05 09:56 PM circuit breakers  
jmcelectric  Offline
Member
Joined: Jan 2004
Posts: 16
anyone know if there is a code rule on feeding a CB in an enclosure with lugs on both sides of the CB,if it matters which side of the CB is the feed side and which side is the load side? thanks


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#96611 - 12/12/05 10:17 PM Re: circuit breakers  
Roger  Offline
Member
Joined: May 2002
Posts: 1,716
N.C.
Basically this would come down to the manufactures instructions on the breaker or enclosure, or any attached labels indicating Line/Load on either the breaker or enclosure.

Roger


#96612 - 12/12/05 10:25 PM Re: circuit breakers  
Ron  Offline
Member
Joined: Mar 2002
Posts: 582
White Plains, NY
Some breakers are listed line/load. Some are listed for reverse feed. Check the instructions.
Code is however interested in "On" is up when the handle moves vertically.


Ron

#96613 - 12/13/05 04:05 AM Re: circuit breakers  
e57  Offline
Member
Joined: May 2003
Posts: 2,876
S.F.,CA USA
Not exactly sure of the question, but take a look at 404.6, and 404.7. And 408.19.

I believe that in codes past, it was not only required to have up be ON, and down be OFF, but also connections on top be LINE, and below be LOAD. Making the handle in the on position point toward LINE, and that is pretty standard. (At least the way I learned it.) It may have been part of Phase Arrangement codes? I think all switches are made that way anyway, with terminals marked LINE on top, I can't remember ever seein' any that were not made that way. Except double throws.... In fact the only circuit breakers I can think of that were not also like that are FPE, and only some of them.

Darn good question....


Mark Heller
"Well - I oughta....." -Jackie Gleason

#96614 - 12/13/05 11:04 AM Re: circuit breakers  
JBD  Offline
Member
Joined: Jul 2001
Posts: 599
WI, USA
UL listed circuit breakers are always allowed to be top or bottom feed unless specifically marked with "line and load".

The actual UL wording for category DIVQ is "Line and load markings on a molded case switch are intended to limit connections there-to as marked."

Breakers in panels can be back feed, 408.36(F)

Disconnect switches may be top or bottom feed, 404.6. However, fuses can not be back feed, 408.39.


#96615 - 12/13/05 07:16 PM Re: circuit breakers  
iwire  Offline
Moderator
Joined: Jan 2003
Posts: 4,391
North Attleboro, MA USA
Quote
Disconnect switches may be top or bottom feed, 404.6.


I do not understand.

How could I bottom feed a disconnect switch and comply with 404.6(C)?

[This message has been edited by iwire (edited 12-13-2005).]


Bob Badger
Construction & Maintenance Electrician
Massachusetts

#96616 - 12/14/05 10:49 AM Re: circuit breakers  
JBD  Offline
Member
Joined: Jul 2001
Posts: 599
WI, USA
A single throw inverted design where the fuses and the switch blades are "above" the line contacts. Bolted pressure type switch blades are allowed to be barriered. And of course those applied per the exception as well as double throw designs.

edit: finished thought after hitting "submit" too early.

[This message has been edited by JBD (edited 12-14-2005).]


#96617 - 12/15/05 10:01 AM Re: circuit breakers  
SteveFehr  Offline
Member
Joined: Mar 2005
Posts: 1,205
Chesapeake, VA
The question about reverse feed came up for me recently when we routed the current path through a switchboard temporarily during an install and reverse-fed a solid-state breaker (800A breakout ACB) that's normally not reverse-fed. When you're talking about Bus Ties and other similar applications, there really is no clear-cut line or load with respect to fwd/reverse feed.

One of our techs was concerned about it, but I couldn't think of anything at all that would prevent it. (It ended up working fine.) What part of a solid state breaker would even know whether the A/C current was coming or going? There shouldn't be anything in the old thermal-magnetics that would be sensitive to load direction.

[This message has been edited by SteveFehr (edited 12-15-2005).]

[This message has been edited by SteveFehr (edited 12-15-2005).]


#96618 - 12/15/05 01:43 PM Re: circuit breakers  
Dave T  Offline
Member
Joined: Jan 2005
Posts: 155
Waukesha, WI, USA
Look at the breaker. If it can only be feed from the "on" end it will be marked with line and the other end load. Otherwise there are no markings and it can be feed from either end.
The objective if you are allowed to take off the cover to change trip units of ass accessories or not and if so if you would be exposed to live parts when doing so.
When feed from the 'ON' end which the breaker on the 'OFF' position and the moving contacts are up and away from the energized stationary contacts then all parts from the toggle and below will be de-energized.
One example of a breaker marker with Line-Load is a breaker that has interchangable trip units the may be identifies as 'IT" of a diagram. Breakers marked on a diagram marked as 'NIT' must have noninterchangable trips.
Also note that breakers that can be reverse fed are factory sealed with a seal across the cover and base moldings. Also, breakers that have electronic trips most likely can be reverse feed because ratings plugs that are used to change the rating of the breaker do not expose the electrician to live parts.
But, there is no substitute for a qualified person who has experience with working of this gear and who is well versed is safe electrical practices and procedures. Such a person who would recognize this application and proceed accordingly.


#96619 - 12/17/05 10:04 PM Re: circuit breakers  
harold endean  Offline
Member
Joined: Feb 2002
Posts: 2,233
Boonton, NJ
OK, here is an example I just saw. The breaker itself doesn't say anything about Line/Load on the breaker. However the label on the back of the cover shows the line side of the main breaker is on the top and the load side on the bottom. Then I would assume that the manufacture wants it that way, and if we don't install it properly, we could fail inspection.


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