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#96610 - 12/12/05 05:56 PM circuit breakers
jmcelectric Offline
Member
Registered: 01/20/04
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 06:17 PM Re: circuit breakers
Roger Offline
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Registered: 05/18/02
Posts: 1716
Loc: 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
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#96612 - 12/12/05 06:25 PM Re: circuit breakers
Ron Offline
Member
Registered: 03/13/02
Posts: 582
Loc: 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.
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#96613 - 12/13/05 12:05 AM Re: circuit breakers
e57 Offline
Member
Registered: 05/27/03
Posts: 2876
Loc: 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....
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"Well - I oughta....." -Jackie Gleason
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#96614 - 12/13/05 07:04 AM Re: circuit breakers
JBD Offline
Member
Registered: 07/12/01
Posts: 599
Loc: 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.
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#96615 - 12/13/05 03:16 PM Re: circuit breakers
iwire Offline
Moderator
Registered: 01/05/03
Posts: 4391
Loc: 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).]
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Bob Badger
Construction & Maintenance Electrician
Massachusetts
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#96616 - 12/14/05 06:49 AM Re: circuit breakers
JBD Offline
Member
Registered: 07/12/01
Posts: 599
Loc: 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).]
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#96617 - 12/15/05 06:01 AM Re: circuit breakers
SteveFehr Offline
Member
Registered: 03/19/05
Posts: 1195
Loc: 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).]
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#96618 - 12/15/05 09:43 AM Re: circuit breakers
Dave T Offline
Member
Registered: 01/22/05
Posts: 155
Loc: 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.
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#96619 - 12/17/05 06:04 PM Re: circuit breakers
harold endean Offline
Member
Registered: 02/16/02
Posts: 2233
Loc: 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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