We are working on a project where there are many remote devices reporting back to a SCADA system. They are devises such as float switches, pressure transducers, pressure switches, control panel signals visa dry contacts etc. The wiring is either individual conductor like 2-#18 or shielded twisted pair. The signaling power will be 24VDC. I am trying to classify this wiring and suspect it falls under section 725 of the NEC and am looking for some assistance. I need to figure this out in order to figure out how many conductors/cables can be in the same conduit.
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wiring classification for devices to SCADA
- Thread starter mjmike
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petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
We are working on a project where there are many remote devices reporting back to a SCADA system. They are devises such as float switches, pressure transducers, pressure switches, control panel signals visa dry contacts etc. The wiring is either individual conductor like 2-#18 or shielded twisted pair. The signaling power will be 24VDC. I am trying to classify this wiring and suspect it falls under section 725 of the NEC and am looking for some assistance. I need to figure this out in order to figure out how many conductors/cables can be in the same conduit.
why would it matter any? none of them are current carrying conductors.
why would it matter any? none of them are current carrying conductors.
Just as an example, the derating factors of 310-15.b.2.a apply in some cases.
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
Just as an example, the derating factors of 310-15.b.2.a apply in some cases.
most of these circuits are going to have currents measured in milliamps. I just do not see any derating being an issue at all. there just is no heat that will be generated in these conductors.
most of these circuits are going to have currents measured in milliamps. I just do not see any derating being an issue at all. there just is no heat that will be generated in these conductors.
I understand that. The power supply itself is only 100w. However, I would still like to be able to know how to go about classifying the wiring.
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
I understand that. The power supply itself is only 100w. However, I would still like to be able to know how to go about classifying the wiring.
if it is a 100W power supply it might well be a class 2 power supply.
if it is a 100W power supply it might well be a class 2 power supply.
I researched the power supply and the manufacturer noted it is not a listed class 2 or class 3 power supply so I think that then means the wiring will be class 1 even though it is only 24VDC.
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
I researched the power supply and the manufacturer noted it is not a listed class 2 or class 3 power supply so I think that then means the wiring will be class 1 even though it is only 24VDC.
that would appear to be the case then.
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