430.32(B)

[Isaiah]

I have a single phase 120VAC, .5 HP, 8FLA motor with an integral thermostat, T3, in a Class I, Division 2, C&D location. Does this satisfy the requirement for thermal OL or does it require separate heater?

 

[augie47]

IMO, it meets the requirement of 430.32(B) but there may be issues beyond that as to its being in a classified location.
For that reason I relocated the thread to the "Hazardous" Forum so some of the guys wit knowledge of that can address it

 

[kwired]

IMO, it meets the requirement of 430.32(B) but there may be issues beyond that as to its being in a classified location.
For that reason I relocated the thread to the "Hazardous" Forum so some of the guys wit knowledge of that can address it

Without looking at what requirements may be, I like the idea for hazardous locations, it has the ability to shut things down when a certain temp is reached regardless of what current may be. Remote thermal or even electronic overloads only respond to current and have no idea what the actual motor surfaces temps may be.

 

[Isaiah]

Without looking at what requirements may be, I like the idea for hazardous locations, it has the ability to shut things down when a certain temp is reached regardless of what current may be. Remote thermal or even electronic overloads only respond to current and have no idea what the actual motor surfaces temps may be.

I think you're right on this Kwired.

 

[Isaiah]

IMO, it meets the requirement of 430.32(B) but there may be issues beyond that as to its being in a classified location.
For that reason I relocated the thread to the "Hazardous" Forum so some of the guys wit knowledge of that can address it

thanks Augie.

 

[augie47]

Without looking at what requirements may be, I like the idea for hazardous locations, it has the ability to shut things down when a certain temp is reached regardless of what current may be. Remote thermal or even electronic overloads only respond to current and have no idea what the actual motor surfaces temps may be.

I agree and IF the motor is listed for that area hopefully that is taken in to consideration in sizing the thermal
My concern would be that the setting of a thermal overload might not be adequate to provide the hazardous location protection but there is a ton of stuff I don;t know about Art 501 so I look forward to other answers.

 

[Isaiah]

I agree and IF the motor is listed for that area hopefully that is taken in to consideration in sizing the thermal
My concern would be that the setting of a thermal overload might not be adequate to provide the hazardous location protection but there is a ton of stuff I don;t know about Art 501 so I look forward to other answers.

For these small 120VAC motors we normally provide a manual motor starter with OL's (e.g. Cutler-Hammer, Allen Bradley, etc). The enclosure itself doesn't have to be explosion proof in CID2 as long as the internal contacts are 'factory-sealed'.

 

[rbalex]

This is a bit difficult to explain:

First, virtually all single-phase motors in Class I, Division 2 must be explosionproof no matter what overload protection technique is used. This is because they generally use some form of switching technique to create the initial rotation direction. Three-phase induction motors don't usually have this issue.

Second, a "new" AHJ (FedOSHA) has entered the arena recently. Under the FedOSHA 29CFR1910.399 definitions of Acceptable, Accepted, and Approved:

Acceptable. An installation or equipment is acceptable to the Assistant Secretary of Labor, and approved within the meaning of this Subpart S:

(1) If it is accepted, or certified, or listed, or labeled, or otherwise determined to be safe by a nationally recognized testing laboratory recognized pursuant to § 1910.7; or
(2) With respect to an installation or equipment of a kind that no nationally recognized testing laboratory accepts, certifies, lists, labels, or determines to be safe, if it is inspected or tested by another Federal agency, or by a State, municipal, or other local authority responsible for enforcing occupational safety provisions of the National Electrical Code, and found in compliance with the provisions of the National Electrical Code as applied in this subpart; or
(3) With respect to custom-made equipment or related installations that are designed, fabricated for, and intended for use by a particular customer, if it is determined to be safe for its intended use by its manufacturer on the basis of test data which the employer keeps and makes available for inspection to the Assistant Secretary and his authorized representatives.
​

Accepted. An installation is "accepted" if it has been inspected and found by a nationally recognized testing laboratory to conform to specified plans or to procedures of applicable codes.
Approved. Acceptable to the authority enforcing this subpart. The authority enforcing this subpart is the Assistant Secretary of Labor for Occupational Safety and Health. The definition of "acceptable" indicates what is acceptable to the Assistant Secretary of Labor, and therefore approved within the meaning of this subpart.​

That is, if a product can be NRTL certified for a specific pur, it must be. Until recently general purpose motors were not NRTL certified; however, in the last few years, some manufacturers have begun to have their motors Class I, Division 2 certified.

NEC [2017] Section 501.125(B)(3) notwithstanding, it is a bit "iffy" not using a NRTL certified motor in Class I, Division 2 and the overload protection technique is irrelevant.

​

 

[Isaiah]

This is a bit difficult to explain:

First, virtually all single-phase motors in Class I, Division 2 must be explosionproof no matter what overload protection technique is used. This is because they generally use some form of switching technique to create the initial rotation direction. Three-phase induction motors don't usually have this issue.

Second, a "new" AHJ (FedOSHA) has entered the arena recently. Under the FedOSHA 29CFR1910.399 definitions of Acceptable, Accepted, and Approved:

That is, if a product can be NRTL certified for a specific pur, it must be. Until recently general purpose motors were not NRTL certified; however, in the last few years, some manufacturers have begun to have their motors Class I, Division 2 certified.

NEC [2017] Section 501.125(B)(3) notwithstanding, it is a bit "iffy" not using a NRTL certified motor in Class I, Division 2 and the overload protection technique is irrelevant.

​

Thanks Bob. The motor is in fact explosion proof with a centrifugal startingswitch and capacitor in addition to the embedded thermostat. It also shows UL approved. I'm going to use a general use snap switch (without overload) for the disconnecting means in accordance with 430.109(C).

 

[rbalex]

Thanks Bob. The motor is in fact explosion proof with a centrifugal startingswitch and capacitor in addition to the embedded thermostat. It also shows UL approved. I'm going to use a general use snap switch (without overload) for the disconnecting means in accordance with 430.109(C).

Looks good to me.