Question about flex cord per 501.140

[batese]

Does anyone have any experience using flex cord in accordance with section 501.140 of the NEC? In particular I am looking to use flexible fieldbus (RS-485) cable in a C1D1 location but have not had any luck in understanding what cable would be acceptable/suitable. Is there a special cable for 501.140 that I should be looking into? I found some good information about MC-HL, ITC-HL and TC-ER-HL cables for haz loc, but I was not able to find much information for cabling acc to 501.140. Any help would be much appreciated.

 

[rbalex]

My first question would be, “What application in Section 501.140 (A) applies?“

 

[batese]

In this case, I think that section 501.140(A)(2) would apply.

 

[rbalex]

In this case, I think that section 501.140(A)(2) would apply.

OK.

Section 501.140 (B) (1) requires the cord be of a type listed for extra-hard usage; I.e., referenced as such in Table 400.4. To my knowledge, no RS-485 cable meets the requirement, mainly because it isn’t a cord.

At this point you would need to appeal to Section 500.8(A)(3) and have a manufacturer validate a cable is or could be NRTL dual certified as a Table 400.4 extra-hard usage cord.

 

[petersonra]

I think you can use any cable you want in conduit because there is no way to terminate it that would be compliant otherwise. Maybe you could use IS barriers.

A lot of detailed information about what you really want to do would be required to determine a solution.

 

[TwoBlocked]

Does anyone have any experience using flex cord in accordance with section 501.140 of the NEC? In particular I am looking to use flexible fieldbus (RS-485) cable in a C1D1 location but have not had any luck in understanding what cable would be acceptable/suitable. Is there a special cable for 501.140 that I should be looking into? I found some good information about MC-HL, ITC-HL and TC-ER-HL cables for haz loc, but I was not able to find much information for cabling acc to 501.140. Any help would be much appreciated.

We typically use 2-pair okanite with TMCX connectors for RS-485 in CID1. The one pair is for the A- / B+ and then use the black from the other pair for ground.

 

[petersonra]

We typically use 2-pair okanite with TMCX connectors for RS-485 in CID1. The one pair is for the A- / B+ and then use the black from the other pair for ground.

Do they make a cable with the correct impedance?

The OP used the term fieldbus in his post. That suggests something other than run if the mill RS485 to me.

In any case, I don't see how a cable can be subbed in as a cord. You would need to run it in conduit or a tray cable.

 

[batese]

We typically use 2-pair okanite with TMCX connectors for RS-485 in CID1. The one pair is for the A- / B+ and then use the black from the other pair for ground.

What is the part number of the okanite cable that you use in C1D1? Is it twisted pair, with 120 ohm resistance?
I wish the client would use hard pipe with seals, but in this case, it floods regularly, and they believe (through experience) that hard conduit is basically a hose that expels into the devices. Attached is an example of the application, its basically an XP electric actuator in a pit, connected to the remote mounted controls via flex XP cables with Hawke 753 conduit seals. Bear with me, I am drawing it in paint, the purple cable is the one I am having trouble finding.

 

[batese]

Do they make a cable with the correct impedance?

The OP used the term fieldbus in his post. That suggests something other than run if the mill RS485 to me.

In any case, I don't see how a cable can be subbed in as a cord. You would need to run it in conduit or a tray cable.

Sorry, fieldbus to most is considered foundation fieldbus. I considered the fieldbus in this case to be CANbus/RS485.

 

[petersonra]

Sorry, fieldbus to most is considered foundation fieldbus. I considered the fieldbus in this case to be CANbus/RS485.

I am pretty sure canbus uses special cable.

Any of these look like they might work. I think they would need to be in conduit though.

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