A Circuit Breaker in panel as a disconnecting means?

[batman2010]

I used to believe that a circuit breaker in panel can be used as a disconnecting means for motor loads like in boiler rooms when the panel is within site until i read Article 430.109 in the NEC (NFPA 70) defines the type of disconnecting means allowed for motors and controllers. I am concluding that it is against the code for a circuit breaker in panel to be considered used as disconnecting means unless it is in a separate enclosure and can be locked in an open position, any body have an input on that?

 

[rcw retired EE]

NEC 430.109 (2) allows the use of a listed molded case cirucit breaker. It does not specify whether the breaker is in a panelboard or a seperate enclosure or part of the motor starter. If the circuit breaker in the panelboard has a locking device that does not get removed when the lock is removed, it is acceptable.

430.102 (B) (2) Exception "...The provision for locking or adding a lock to the controller disconnecting means shall be installed on or at the switch or circuit breaker used as the disconnecting means and shall remain in place with or without the lock installed."


My interpretation of the requirement is to minimize the chances of someone not being able to find the removable style locking attachment when locking out the motor. As long as the locking attchment is fastened in place, it should be per code. There might be an issue with an inspector if you just bolted a padlock hasp to the panel to hold the breaker in the off position. Even though it is effective, it may not be a "listed" breaker or panelboard accessory.

 

[batman2010]

my understanding is a "listed molded case circuit breaker" definition is that it is a single separate breaker that is not part of an electrical panel. I am basing this assumption because in article 430.109(B) it shows the exception to use a circuit breaker in panel (branch circuit overcurrent device) only with motors rated at 1/8 HP, Exhibit 430.20 proves that a branch circuit overcurrent device (circuit breaker in panel) is only permitted to be used under such exception!!!!

 

[Mila15]

The definition of listed per article 100 is: "Equipment, materials, or services included in a list published by an organization that is acceptable to the authority having jurisdiction and concerned with evaluation of products or services, that maintain periodic inspection of production of listed equipment or materials or periodic evaluation of services, and whose listing states that either the equipment, material, or service meets appropriate designated standards or has been tested and found suitable for a specific purpose."

This doesn't mean the breaker has to be in a separate electric panel.

 

[batman2010]

Article 430.109 (B) clearly permits the use of a branch circuit over current device ONLY with motors of 1/8 HP or less, this means that it can't be used for larger motors, also 430.102 mentions the use of a lockable mechanism required when providing a disconnect for such motors, reference to NFPA 70E-2009. With all of this being said, I conclude that it is against the code to use a branch circuit over current device as a disconnect without having a lockable mechanism on the breaker unless the motor is 1/8 HP

 

[DRWeig]

I disagree, batman2010.

because in article 430.109(B) it shows the exception to use a circuit breaker in panel (branch circuit overcurrent device) only with motors rated at 1/8 HP

You're adding words to the code here. To my knowledge, nowhere in the code is a branch circuit overcurrent device defined as "a circuit breaker in a panel."

A branch circuit overcurrent device can be a listed molded case circuit breaker, and that listed molded case breaker can be in a panel or not. A permanent lockable mechanism can be installed on that breaker.

The building I worked in last had a panelboard with six listed molded-case circuit breakers in it, each with a permanent hasp thing for a lockout device. It fed six air handling unit fans of 5 to 20 HP, and it was easily in sight of each motor. Our AHJ had no problem with it.

Google this: panelboard with listed molded case circuit breakers

You'll find that GE, Seimens, Eaton, Schneider, and others sell them.





Best to you,

Goober Dave

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[batman2010]

weather a "branch circuit breaker overcurrent device" is a "circuit breaker in panel" or not, i think we both agree that a circuit breaker in panel is considered a branch circuit overcurrent device and this being said it is only permitted by code to be used for motors under 1/8 hp (code)

 

[itsmoked]

No we don't agree. Did Dave not just give an example? It's not a branch circuit unless it's feeding multiple loads is it?

Keith Cress
kcress -

http://www.flaminsystems.com

 

[batman2010]

Branch circuit definition is The part of a distribution system consisting of circuit conductors, between the final overcurrent protection and the outlet or load attached. [not multiple loads}

 

[DRWeig]

And I'll reiterate: A molded-case circuit breaker can be found in a panelboard. It's allowed to feed a motor of any size, within practical or economic limits, as the disconnecting means if the in-sight condition is satisfied.

For a final word, ASK THE AHJ. All the ones I've dealt with are super happy to get something right before inspection.

Best to you,

Goober Dave

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[waross]

There are three functions that must be provided for a motor circuit;
OVERLOAD protection.
OVERCURRENT protection.
and
DISCONNECTION.
You may be better served with a small manual motor starter in place of the circuit breaker.
That will provide overload and disconnection functions.
The circuit breaker feeding your control panel may fulfill the overcurrent function.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[batman2010]

I would say it has to be a combination starter (starter + disconnect) for it to be considered as means of disconnect. Thank you guys for the input.

 

[waross]

You are free to say whatever you wish in any area in which you have jurisdiction. However I don't believe that the NEC or CEC makes that statement.
Can you quote a rule?

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[DRWeig]

"Means of disconnect" has nothing to do with an automated device (starter or contactor), and I can guarantee that it is not defined your way in the NEC. Means of disconnect is a switch or circuit breaker that can be locked in the open position. The switch or breaker in a combination starter is the means of disconnect if that's the way you want to design it.

As Bill stated, you can call it whatever you want. If you're talking to an AHJ, though, it's my experience that adding definitions and words to the NEC is not something that you want to do.

Best to you,

Goober Dave

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