Intrinsically Safe wiring

[DanijelM]

I have a sump in C1D1 area. Need to install a accelerometer onto a pump to monitor vibrations. The pump shaft is 8ft long. Motor is in C1D2 area. This is where I would read vibe reading.
Accelermeter is I.S. rated. I have matching I.S. barrier.
My question is wiring between accelerometer and I.S. barrier. The clerance around shaft is very tiny. Would need to route cable alongside of the pump shaft. What is permitted? How to protect it from damage? Does it have to be in conduit? I know NEC states "Any of the wiring methods suitable for unclassified locations, including those covered by Chapter 7 and Chapter 8, shall be permitted for installing intrinsically safe apparatus"
Can someone clarify?
Thank you for any response.

 

[DRWeig]

Hi DM,

You're allowed virtually anything by the code. Just a cable with a twisted pair is OK. That's because on the hazardous side of the barrier there isn't sufficient energy available to ignite anything, no matter what happens to your wires.

It's up to you to decide how much physical protection is needed to keep your system in service. As long as your cable is OK by itself, you can also run it through metal tubing of whatever type too.

Let us know how you decide to proceed!

Good on ya,

Goober Dave

 

[itsmoked]

As DR said,just use what you physically need for functionality. Specifically the code is saying any reasonable wiring materials and practice that you would use in a non-EXP environment.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[zappedagain]

You might want to avoid Teflon insulation. The requirements get really odd around Teflon due to its potential to generate ESD events (sparks). Without digging back into the standards I believe you cannot use it.

John D