CL 1, DIV 2 Solenoid Wiring

[mike@bauer]

OK, I have a compressor control panel located in a CL1, DIV2 location. We are using a Nema-4 Enclosure and all CL1, DIV2 components in the enclosure. I am controlling 2 general purpose solenoid valves that are 115VAC and about 24W. In the past, when we used Nema7 enclosures, we would run metal conduit to the valves, with seals, junction boxes and unions. It is very labor intensive. Given the new Nema-4 approach, this metal conduit seems to be a little bit of overkill. Does anyone have any experience in this area who might be able to recommend a flexible cable type that meets the NEC requirements? Preferably one that doesn't require conduit or trays. I have some 14ga MC, but it is overkill and I don't want to hang all that bulk on the solenoid valve.

Thanks in advance for the help!

 

[rbalex]

... Preferably one that doesn't require conduit or trays. ...

You painted us into a corner with that provision.

Until such time that TC-ER is correctly identified as an "open" wiring method as it should be, you're out of luck with a "cable only solution" - unless you REALLY want to stick your neck out with 336.10(4).

In the mean time, you may want to support Proposal 7-118 [Log #4088 NEC-P07] for the 2011. NEC.

 

[mike@bauer]

messenger wire

messenger wire

Do you think a piece of bent tubing would constitute a messenger wire? Then we could tie wrap it to the outside of the tubing. To clarify, the runs are only 4 feet or so from enclosure to solenoid.

 

[kameele]

We've used pre-made MI cable whips to connect SOVs in both Div 1 and 2 locations. They do require a body at the SOV for splicing, but no other conduit or seals.

on another note--505.105(3) would suggest that wiring methods would not require such heavy duty methods anyway. I have a white paper from ASCO saying that thier SOVs that are listed as explosion-proof do not require a seal, even in Div 1 areas. Major source of discussion with customers at times, so we end up putting in seals as being cheaper than prolonged talking :roll:

 

[rbalex]

For the 4' runs, I see no reason to avoid Type MC. In Division 2, standard MC is fine, the only concern is using appropriate fittings and making sure they are stress free.

Kameele's suggestion is fine too, with the same general provisos.

I believe kameele was referring to 501.105(B)(3). I agree that "heavy duty methods" don't seem necessary; however, they are the only wiring methods permited by 501.10 (B).

Another critical issue that is often overlooked is the need for proper hazardous location grounding/bonding (501.30), no matter how robust or fragile the wiring method may need to be.

 

[dakins]

Sometimes it just works out better relocating the solenoid valves outside the classified area. Then run tubing wheres needed.