exp
Member
- Location
- SF Bay Area
- Occupation
- Electrical Engineer
I need advice from experts here.
My understanding is that no low-voltage wiring (which includes Ethernet) is allowed to exit an enclosed raceway (conduits, junction boxes) that contains line voltage. I am not sure about the exact reasoning but I assume there is the chance that wiring might fail and low voltage conductor could short with line voltage conductor. Low Voltage count run in the same raceway as line voltage assuming it is never brought out (e.g., communication wire from one device to a relay which are both installed in enclosed junction boxes).
There is so much (contradicting) discussion about this but nothing I can find provides clear NEC references. It just sounds people have "opinions" they categorically defend. I am sure there must be some exceptions:
My understanding is that no low-voltage wiring (which includes Ethernet) is allowed to exit an enclosed raceway (conduits, junction boxes) that contains line voltage. I am not sure about the exact reasoning but I assume there is the chance that wiring might fail and low voltage conductor could short with line voltage conductor. Low Voltage count run in the same raceway as line voltage assuming it is never brought out (e.g., communication wire from one device to a relay which are both installed in enclosed junction boxes).
There is so much (contradicting) discussion about this but nothing I can find provides clear NEC references. It just sounds people have "opinions" they categorically defend. I am sure there must be some exceptions:
- Emporia's Vue3 is an energy meter for fixed install inside a residential breaker panel. It features an Ethernet connector. It is UL certified. Emporia insists it is safe and legal to bring in Ethernet into the breaker panel to connect with their Vue3
- Enphase Envoy is an enclosure that connects to line voltage and also has an Ethernet connector. While we may argue that the Ethernet cable itself cannot run through the same conduit as the line voltage, even if we bring out Ethernet via another knockout, it would still exit the "enclosed raceway"
- There are Panduit 600V Ethernet cables which suggest they can be legally in the same conduit as line voltage. In this case, it seems the only reason is that the cable can sustain 600V (like line voltage) but I could still run them in the same conduit as line voltage and bring them in/out via clamps in a junction box, for example.
- Which of these examples are legal? Is Emporia correct?
- What are the exact conditions according to NEC to run low voltage (in particular, Ethernet) in the same conduit/junction box/panel as line voltage?
- What is the exact reasoning? Is it risk of low voltage shorting with line voltage? Is it insulation capabilities of low voltage conductors (which are usually, but not always, <600V rated)?
- In example (1), it wouldn't make sense if there are no additional conditions on how to bring in the Ethernet cable. No minimum spacings, no insulation, no requirements on bushings etc?