Flex I/O module in Class II, Div 2 enclosure

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rambopg

Member
Location
Toronto, ON
Hello everyone!


This is my first post ever. I would like to know if Allen-Bradley Flex I/O Ethernet module and input card can be installed inside a Type 4 (NEMA 4) enclosure for Class II, Div 2 Group G (Powdered sugar @ 370 deg C, Wheat Flour @ 360 deg C)? It is for Canada, however I wouldn't mind your perspective from NEC side and I can compare it to CEC/OESC.


The Flex I/O Ethernet adapter is a heat producing equipment T4A - 120 deg. C (Model 1794-AENT) but it is only rated for non-hazardous or Class I, Div 2 locations
The Flex I/O Digital Input module is a heat producing equipment T3C - 160 deg. C (Model 1794-IB16XOB16P) but it is only rated for non-hazardous or Class I, Div 2 locations.


regards,
PG
 

rbalex

Moderator
Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
First, in Canada, you are most likely dealing with Zones rather than Divisions.

Second, Class I equipment is not automatically rated for Class II [See NEC Section 502.5 for example.]

Third, an NEC Type 4 enclosure is not generally rated as dusttight, [Table 110.28, IN No.1] the minimum NEC Class II, Division 2 requirement. [Section 502.10(B)(2)]

All that said, IF your enclosure includes another rating that is dusttight, THEN you probably are suitable.
 

rambopg

Member
Location
Toronto, ON
Thanks Bob.

I agree that in Canada we have Zones, however we can still use Class/Division system.
The Canadian Electrical Code does allows the usage of Type 4 enclosure for certain equipment in Class II, Div 2. Below is an excerpt from the code.

And yes I know Class I equipment is not equivalent to Class II. However, I fail to understand how this equipment can pass Class I but not Class II considering it is a Ethernet/IP module which produces heat.

regards,

J18-258 Switches, controllers, circuit breakers, and fuses, Class II, Division 2
Enclosures for switches, motor controllers, circuit breakers, and fuses, including push buttons, relays,
and similar devices, shall be either an Enclosure Type 4 or 5, or
a) be provided with telescoping or close-fitting covers or with other effective means to prevent the
escape of sparks or burning material; and
b) have no openings, such as holes for attachment screws, through which, after installation, sparks or
burning material might escape, or through which exterior accumulations of dust or adjacent
combustible material might be ignited.
 
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