422.31(c)

[RICK NAPIER]

Does anyone know the logic behind this new requirement in the 2011? I am talking about the fact that you are no longer allowed to use a lockable disconnect out of sight for a motor-operated appliance over 1/8 horsepower. I would like to know what reasoning went behind this.

 

[augie47]

Below is the substantiation given by the CMP. Apparently in the '08 Code, 422.31 and 422.32 conflicted.

Substantiation: ​

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This change is intended to clarify the requirements of these
sections. As presently worded, there is conflict and confusion with the
requirements of Section 422.31(B) and those of section 422.32. Section
422.31(B) allows the branch-circuit switch or circuit breaker disconnecting
means for an appliance rated over 1/8 horsepower to be locked in the open
position. However, section 422.32 requires that for a motor driven appliance
the disconnecting means must be within sight from the motor controller. As
such, this section prohibits the ?capable of being locked in the open position.?
To clarify the intent, the over 1/8 Horsepower has been removed from section
422.31(B) and a new section 422.31(C) has been created to addresses
appliances rated over 1/8 horsepower. This should make it easier for users of the
NEC to understand that for appliances with a motor rated over 1/8 horsepower,
the disconnecting means requirements are more restrictive (as presently worded
in section 422.32). Incorporating the requirements of section 422.32 into new
section 422.31(C) makes sense. With this change, existing section 422.32 can
be deleted. Since the code requirements reference an appliances horsepower
rating, a motor driven appliance is implied; therefore, there is no need to
reference motor driven appliance. The reference to motor controller is
unnecessary too, as the controller is part of the appliance. If not, then the
equipment should be subject to the installation requirements of Article 430.
The Exception was modified by deleting the reference to ?motor driven? and
?motor controller? to correlate with new section 422.31(C). Again, the intent of​

this change is to remove the conflicting and confusing code language!

 

[augie47]

note: You can review the ROPs for yourself here:
http://www.nfpa.org/assets/files/PDF/ROP/70-A2010-ROP.pdf

 

[RICK NAPIER]

Thanks for that info. Now all I need to figure out is why they made that change to 422-32 in the 2002 NEC.

 

[jumper]

Is this what you want?

20- 9 - (422-31 and 422-35): Accept
SUBMITTER: Bryan D. Stokes, SGS Architects Engineers
RECOMMENDATION: Relocate after 422-35 (including
exceptions) below 422-31(b), and renumber section as 422-32.
Delete FPN No. 1 of 422-31(b) and renumber FPN No. 2 as FPN
No. 1. Renumber remaining sections accordingly.
SUBSTANTIATION: This proposal will make the code more user
friendly.
PANEL ACTION: Accept.
NUMBER OF PANEL MEMBERS ELIGIBLE TO VOTE: 12
VOTE ON PANEL ACTION:
AFFIRMATIVE: 11
NOT RETURNED: 1 Ryan

 

[Dennis Alwon]

I think the intent was not to change anything but to clarify it.

 

[raider1]

I think the intent was not to change anything but to clarify it.

I agree.

As written in the 2008 NEC 422.31(B) allowed 1/8 HP or more motor driven appliances to use a breaker lock on a remote panel to constitute the required disconnecting means.

But 422.32 which deals with motor driven appliances did not allow the breaker lock on the remote branch circuit breaker to be used as the required disconnecting means. So there was a conflict and the CMP agreed that 422.31(B) should only apply to appliances rated at over 300 volt-amps and not to motor drivewn appliances.

Chris

 

[Twoskinsoneman]

My question is why is it unsafe to use the breaker with a breaker lock as the disconnect on these over 1/8 hp appliances? Was the actual reason ever given in the ROPs?