Analog signals cables and DC power cables in the same conduit

[josealjim]

Hi everyone,
WHat do you think about running the analog signal cables (pyranometer and TC at the solar field ) into the same conduit than DC power cables?
The trench for the DC power cables is already covered so if we dont open it again to install another conduit we would have to run the analog signal cables into the same conduit. Another option is to transfer the data with wireless adapter supplied by 230 v from another part of the building (it would be more expensive)

Could I run the cable into the same conduit?

Thanks

 

[don_resqcapt19]

You might have an issue with 725.136 depending on the rating of the power supply for the instruments.

 

[jaggedben]

690.4(B) would prohibit it as well.

 

[MWh_Pro]

Hi josealjim,

Beyond that it is possibly not safe electrical practice, it increases the possibility of introducing inverter switching noise or induced overvoltages on your analog sensor wires. The noise would be particularly notable in an ungrounded, non-isolated array where the DC voltage's reference to ground oscillates at the inverter's switching frequency. Not sure how your pyranometer and sensor wires are protected from noise (e.g. shielded/unshielded) but that's besides the point. Set yourself up for success, and give the wires their own conduit!

Cheers,
Dave

 

[don_resqcapt19]

690.4(B) would prohibit it as well.

That is 690.31(B) in the 2014 code.