means of disconnect for a motor

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wyboy

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Does a shunt trip qualify as a means of disconnect for a motor if the button for the shunt trip is in site but the shunted breaker is in another room.
 

charlie b

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I agree. It's a worker safety consideration. The intent is that a person working on a motor can see the disconnecting means, and be assured that nobody is about to close it.
 
In my opinion no.

See 430.103 / 430.108 / 430.109
430.103 would not prohibit it, since the shunt trip actuates a device that opens all phases.

430.108/9 specifically lists modled case CB or MCP that can be shunt trip actuated.

Since the shunt trip is part of the device, it would be an acceptable method to provide a means of disconnect in compliance with NEC and have the shunt trip actuator within sight of the motor and the actual breaker is out of sight. (Another example how screwly written our beloved Codebook is.);)

OSHA - on the other hand - is much clearer on providing guidelines for Lock-Tag provision where the objective is to protect workers from unexpected release of energy that may cause harm to them. They are very clear that only direct disconnection of the power conductive/switching device is acceptable and that it should be mechanically pervented from accidental re-closure. (So shunt trip or stop button in the control circuit are unacceptable means of LOCKING OUT THE ENERGY source.)
 
I can not agree with you here, it 430.103 does require the disconnecting means to open the ungrounded conductors. The disconnecting means the OP describes closes a control circuit.
The operation of the shunt trip results in the opening of ALL ungrounded conductors of the motor or controller power circuit for which the device is the means of disconnect.

As I said it is badly written and should mean what you say it should, alas it does not say that.
 

charlie b

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The operation of the shunt trip results in the opening of ALL ungrounded conductors of the motor or controller power circuit for which the device is the means of disconnect.
Pushing a shunt trip button does not disconnect any ungrounded conductors. Rather, it gives a command to a breaker that is located (per the OP's description) in a different room. It is only when that breaker obeys the command that all ungrounded conductors are disconnected. So it is the breaker itself, and not the pushbutton, that constitutes the disconnecting means. That breaker has to be within sight.

The pushbutton, once pushed and released, cannot prevent a person, in the other room, from re-closing the breaker. A person working on the motor would not see that happen.

430.102(B) would not allow what the OP has described. There are exceptions that might apply, but the OP did not mention an intent to apply them.
 
Pushing a shunt trip button does not disconnect any ungrounded conductors. Rather, it gives a command to a breaker that is located (per the OP's description) in a different room. It is only when that breaker obeys the command that all ungrounded conductors are disconnected. So it is the breaker itself, and not the pushbutton, that constitutes the disconnecting means. That breaker has to be within sight.

The pushbutton, once pushed and released, cannot prevent a person, in the other room, from re-closing the breaker. A person working on the motor would not see that happen.

430.102(B) would not allow what the OP has described. There are exceptions that might apply, but the OP did not mention an intent to apply them.
Disagree with your reading. Where is the prevention from reclosing is written in the NEC? You're reading something that is not there, you're reading intent that is not spelled out, therefore it is an invalid part of the argument.

The circuit breaker, including the shunt trip and its actuator are ONE complex device. Some parts are within sight and some are not.

If I have a circuit breaker with a 50' long cable operated handle where the actual circuit breaker is out of sight, but the handle is within sight would that not be acceptable?

I maintain that the NEC does NOT prohibit either of the above.

(Again the NEC is badly writen in this part.)
 
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charlie b

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Disagree with your reading. Where is the prevention from reclosing is written in the NEC? You're reading something that is not there, you're reading intent that is not spelled out, therefore it is an invalid part of the argument.
You are welcome to disagree, and I disagree right back at you. What I offered was a good reason for having the disconnect in sight. I agree that my good reason is not spelled out in the NEC, and I do not offer it as a part of my argument. The words are clear enough, without adding any interpretation of intent. The disconnecting means must be in sight. Period!
The circuit breaker, including the shunt trip and its actuator are ONE complex device. Some parts are within sight and some are not.
The book does not say that ?some part of the disconnecting means must be in sight.?
If I have a circuit breaker with a 50' long cable operated handle where the actual circuit breaker is out of sight, but the handle is within sight would that not be acceptable?
It would not.
I maintain that the NEC does NOT prohibit either of the above.
And I maintain that it prohibits both.
(Again the NEC is badly written in this part.)
The NEC is badly written in many parts. But I see nothing ambiguous in the statement that the disconnecting means must be in sight.
 
You are welcome to disagree, and I disagree right back at you. What I offered was a good reason for having the disconnect in sight. I agree that my good reason is not spelled out in the NEC, and I do not offer it as a part of my argument. The words are clear enough, without adding any interpretation of intent. The disconnecting means must be in sight. Period!

The book does not say that ?some part of the disconnecting means must be in sight.?

It would not.

And I maintain that it prohibits both.

The NEC is badly written in many parts. But I see nothing ambiguous in the statement that the disconnecting means must be in sight.
So how much you want to be that in a court of law you would loose?:D
 
[EDITED QUOTE FOR TYPOS]
When you lose really bad it is LOOSE:)

[My money is on Charlie.
That's why you have lawyers.....and not argue YOUR own case in court:D

I have a 100:1 that he would loose.....

As you can see from my previous posts I am not disagreeing that he SHOULD be right.

What I am saying that the NEC states it so that it could be argued AND won in a Court of Law that the actuator of the disconnecting means is part of the device, in sight from the motor and there is no implied or direct reference that the device should be observable on a continuous basis. (Which Charlie said it deos.)

Just take the simple fact that the operator sometimes would be facing away from the means of disconnect, turning his back to it, even for extended periods of time. There could be a bank of disconnects, several people working in the same area and someone would close the wrong disconnect and so on.

What I am saying is that only the OSHA described LoTo procedure would prevent an accident, the NEC alone does not.

A badly written safety procedure can be more dangerous than one that is not written by imbuing the operator with a false sense of security. This is the case with this NEC paragraph WHEN it is tried to be used as a safety measure.
 

charlie b

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I have a 100:1 that he would loose....
I?ll take that bet. Put me down for two pennies. You can buy me a bus ticket home.

What I am saying . . . the actuator of the disconnecting means is part of the device. . .
The code does not say that ?part of the disconnecting means shall be within sight.? The requirement of 430.102(B), coupled with the definition of ?disconnecting means,? in article 100, does not leave room for treating part of the means differently from another part of the means.

. . . there is no implied or direct reference that the device should be observable on a continuous basis. (Which Charlie said it does.)
The definition of ?in sight from,? in article 100, says exactly that. The one item must be visible from the other item. If a person turns his back, that does not change the fact that the one item is still visible (i.e., capable of being seen).
 
The code does not say that “part of the disconnecting means shall be within sight.” The requirement of 430.102(B), coupled with the definition of “disconnecting means,” in article 100, does not leave room for treating part of the means differently from another part of the means.
Nor does it say that it needs to be fully or entirely within sight.

Again, I repeat the question: if you have a disconnect with an extended operator, such as cable operators for a CB or MCSW, would not the operator being in sigth would fulfill the requirements and meet your implied requirement that the meaning of within sight as being able to observe if anyone is to manipulate the operator?

I have rasied other points that you choose not to address. Usually in court you do not have that luxury.


"Disconnecting Means.
A device, or group of devices, or other means by which the conductors of a circuit can be disconnected from their source of supply."


Neither the above, nor



" (B) Motor. A disconnecting means shall be provided for a motor in accordance with (B)(1) or (B)(2).
(1) Separate Motor Disconnect.


A disconnecting means for the motor shall be located in sight from the motor location and the driven machinery location.

(2) Controller Disconnect.


The controller disconnecting means required in accordance with 430.102(A) shall be permitted to serve as the disconnecting means for the motor if it is in sight from the motor location and the driven machinery location.

Exception to (1) and (2): The disconnecting means for the motor shall not be required under either condition (a) or condition (b), provided the controller disconnecting means required in accordance with 430.102(A) is individually capable of being locked in the open position. 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.
(a) Where such a location of the disconnecting means for the motor is impracticable or introduces additional or increased hazards to persons or property
(b) In industrial installations, with written safety procedures, where conditions of maintenance and supervision ensure that only qualified persons service the equipment
FPN No. 1: Some examples of increased or additional hazards include, but are not limited to, motors rated in excess of 100 hp, multimotor equipment, submersible motors, motors associated with adjustable speed drives, and motors located in hazardous (classified) locations.
FPN No. 2: For information on lockout/tagout procedures, see NFPA 70E-2004,


Standard for Electrical Safety in the Workplace."

does state that the device and all its components should be fully visible from the equipment they serve. What the NEC does not specifically prohibit, it allows.

Nor does it prohibits the installation of the disconnecting means with the front facing away from the operator where the disconnect 'box' would be visible to the operator but not the position of the handle. Nor does it state that it should be identifiable as belonging to the specific equipment if it is installed with many others. So would you restate again what is the intent of the NEC with this requirement, because I just listed a few issues that possibly hinder that intent. What is your resolution?

 
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charlie b

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Nor does it say that it needs to be fully or entirely within sight.
It says the disconnecting means must be within sight. That is all it needs to say. Try to explain to the judge that half of your installation was in compliance.
 
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