General purpose switch in Class 1 Div.I rated explosion proof device housing

[sselman]

I am curious if it is acceptable to use a general purpose toggle switch rated for the intended load and voltage to be placed in a device housing rated for Class 1 Div.I installations or would I need to technically get agency approval on the assembly as a whole?

Basically I want to mount a GP switch inside the same device enclosure used for rated Class 1 Div.I controls (switch).

I would imagine the switch may need to be encapsulated or hermetically sealed in this application but finding a suitable 3PDT ON-OFF-ON 3 position switch is not easy and the one approved device we have been using has an inconsistent but always long lead time causing supply chain to plan and do work.

The switch is used to change directions on an XP rated AC motor.

Thanks

 

[rbalex]

How is the switch operated?

 

[sselman]

The switch would be actuated using the external actuator of the flameproof device body. The actuator internal to the device body engages the switch bat. Basically substituting a GP switch for the switches normally certified for this use.
I currently use a Crouse Hinds DSD-SR30332 in this application and haven't found a suitable class rated equivalent.

My concern is with the following exerpt from the NEC.

501.115 Switches, Circuit Breakers, Motor Controllers, and Fuses.
(A) Class I, Division 1. In Class I, Division 1 locations, switches, circuit breakers, motor controllers, and fuses, including pushbuttons, relays, and similar devices, shall be provided with enclosures, and the enclosure in each case, together with the enclosed apparatus, shall be identified as a complete assembly for use in Class I locations.

 

[rbalex]

501.115 Switches, Circuit Breakers, Motor Controllers, and Fuses.
(A) Class I, Division 1. In Class I, Division 1 locations, switches, circuit breakers, motor controllers, and fuses, including pushbuttons, relays, and similar devices, shall be provided with enclosures, and the enclosure in each case, together with the enclosed apparatus, shall be identified as a complete assembly for use in Class I locations.

The key is the word identified. It does NOT mean listed or labeled.

Identified (as applied to equipment). Recognizable as suitable for the specific purpose, function, use, environment, application, and so forth, where described in a particular Code requirement.

FPN: Some examples of ways to determine suitability of equipment for a specific purpose, environment, or application include investigations by a qualified testing laboratory (listing and labeling), an inspection agency, or other organizations concerned with product evaluation.​

The FPN is misleading and many people believe to be "identified" requires "listing" or "labeling"; however, those are only "some examples" - they aren't the exclusive means. Because this is such a common problem, especially in hazardous locations, Code Making Panel 14 (CMP14) attempted to have it's own definition of identified as it applied to Articles 500-516. When CMP1 and the Technical Correlating Committee denied it, CMP14 focused on the word suitable instead. The result was Section 500.8(A):

500.8 (A) Suitability. Suitability of identified equipment shall be determined by one of the following:
(1) Equipment listing or labeling
(2) Evidence of equipment evaluation from a qualified testing laboratory or inspection agency concerned with product evaluation
(3) Evidence acceptable to the authority having jurisdiction such as a manufacturer?s self-evaluation or an owner?s engineering judgment.

In addition, Section 500.4(B)FPN No.1 Note AHJ's should "... be familiar with recorded industrial experience as well as with the standards..."

Personally, with a properly installed external operator, I wouldn't hesitate to accept your assembly as described.

 

[sselman]

Thank you Bob, this was very helpful.