(C) Conductors of Different Systems.
(1) 1000 Volts, Nominal, or Less. Conductors of ac and dc
circuits, rated 1000 volts, nominal, or less, shall be permitted to
occupy the same equipment wiring enclosure, cable, or raceway.
All conductors shall have an insulation rating equal to at
least the maximum circuit voltage applied to any conductor
within the enclosure, cable, or raceway.
Secondary wiring to electric-discharge lamps of 1000 volts or
less, if insulated for the secondary voltage involved, shall be
permitted to occupy the same luminaire, sign, or outline lighting
enclosure as the branch-circuit conductors
Informational Note No. 1: See 725.136(A) for Class 2 and
Class 3 circuit conductors.
Informational Note No. 2: See 690.4(B) for photovoltaic source
and output circuits.
Low voltage and high (in the consumer sense) voltage in the same raceway is not really the issue. It is power (Chapter 3) versus Limited Power (which happens to also be limited in maximum voltage).Low voltage and high voltage can not be on the same race way. The can also interfere with the transfer of data.
That last part is true of serial such as RS-232 but false on Ethernet which has a notch at 50-60 Hz. Allen Bradley did a lot of testing on this with UTP. I’ve seen grounding issues but not interference in Ethernet. BUT it’s a huge issue with RS-232 and sometimes RS-485.Low voltage and high voltage can not be on the same race way. The can also interfere with the transfer of data.
It is not a voltage issue. You CAN purchase 600 V insulated AWM CAT cable from Belden for example. It is used in some drives and switchgear. Same jacket as any other 600 V rated power cable. This is just like running special high voltage XHHW wiring with 5 kV jackets in the power side of MV switchgear and motor starters.Low voltage and high (in the consumer sense) voltage in the same raceway is not really the issue. It is power (Chapter 3) versus Limited Power (which happens to also be limited in maximum voltage).
That information is correct in unshielded low speed communications. There are three things that make Ethernet inherently different. First every electromagnetic emission is a combination of an electrostatic and magnetic field. The twists in twisted pairs are important. Every twist sees the fields in the opposite polarity so it totally cancels both fields. Second there is 1500 V of isolation across a balun at both ends so it breaks any magnetic induced field that could be induced by the loop. Shielding helps improve resistance to electrostatic fields if you use ScTP instead of UTP but since both ends are grounded it enhances magnetic fields by making the shield a loop antenna. In practice around power it’s mostly magnetic fields so shielding may or may not improve things but generally makes it worse."I mean inside say an industrial control panel you can literally have a CAT 6’with a 600 V AWM rating tie wrapped to 500 MCM THWN-2. It is legal and it works. "
Wow, if you say so I believe you...We were always required to not parallel it with power, and to cross at right angles.
The cable crossing thing is real and often quoted. There are two reasons. If you have two cables in parallel you can induce a voltage from one to the other. Obviously this is minimized in straight cables. In twisted pair every half twist exposes it to the opposite field so it is 100% cancelled. Also in the near field you get a 3 dB interference rejection by angling cables 90 degrees in terms of treating the cables as antennas and treating them as antennas. So there is a lot of wisdom in this when it comes to say low level analog signals from thermocouples, load cells, RS-232, and even 10 VDC analog signals. Very different from say 4-20 mA current loops, RS-485, Ethernet, and CAN, which are much more interference resistant.
I'm not going to disagree with you on Ethernet cabling. I was in the force and motion control world, hydraulic and electric. Our control devices (servo, proportional, and pressure valves) (electric servo motors) typically had frequency response to the very low hundred Hertz. Our signal cabling was typically high impedance (4.7-47 kOhm), rarely 4-20 mA, and in a cable containing 4 to perhaps 12 "cores" including DC power. Coupling from power, depending on level, would commonly be seen in the controlled variable OR in the intentional dither by the electronic device. Frankly, the addition to the dither wasn't usually a problem. The beating with dither signals did weird things however. I often found 2 problems, interrupted shielding and parallel runs, to create these symptoms. In a control panel, I requested 12" spacing to power cabling if parallel, and 90 degree crossing when crossing was required. More than 1 time we found magnetic shielding to help things (often a sleeve of EMT). We denied responsibility if signal (with their DC power) cables shared conduit from machine to cabinets.
Yes, the manufacturer can install it that way in their equipment, but even inside the listed equipment the electrician cannot install it that way....I mean inside say an industrial control panel you can literally have a CAT 6’with a 600 V AWM rating tie wrapped to 500 MCM THWN-2. It is legal and it works. But it’s also part of a Listed assembly...the manufacturer has to get an NRTL to approve the panel. But the moment it exits the enclosure it falls under NEC rules and needs separate raceway.
I'm not going to go and try to find it because it was years ago, but suffice it to say that actual tests were done by a cable manufacturer and other interested parties that show that there is no effect on the data on unshielded UTP when in the proximity of wiring carrying power. I even think the tests were done upping the potential beyond the usual 120/240. Ethernet is pretty damn robust.It is interesting and thus-- catches my attention when someone shows confidence albeit assertiveness in making a point.
I'm anxious to hear what your "debunking" ideas are... Now, try debunking that.