Bonding metal conduit to cable tray for LV systems

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bahogge

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I have received informal pushback from construction teams for requiring conduit bonding to cable tray for LV telecom raceway infrastructure. The way I interpret the code is that all of that raceway infrastructure shall be electrically continuous back to the TGB. This means every 1" conduit for a runout to the data outlets on the floor needs to be bonded to the cable tray. The cable tray sections are bonding to be electrically continuous and that cable tray system is connected to the telecom ground bar.

Owners are hearing that this is a waste of time and money and there are plenty of installations (right or wrong) that don't follow this strategy.

To me, the code is written around power circuits but there is no exception or clarification for voltage level to dismiss LV raceway. Am I in the right or am I requiring grounding and bonding that is above and beyond? Thanks for the input.
 
Art 800 is for comm circuits and is stand alone from the first 7 chapters. That being said, see art 800.110 for wiring within the building. IMO you are correct for requiring connection to the tray.
 
Telecom raceways do not require bonding, as 90.3 states chapter 8 is independant of the NEC, unless chapter 8 gives you a rule referencing chapter 1-7 you ignore the rest of the NEC.
 
tom baker said:
Telecom raceways do not require bonding, as 90.3 states chapter 8 is independent of the NEC, unless chapter 8 gives you a rule referencing chapter 1-7 you ignore the rest of the NEC.
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800.110 Raceways for Communications Wires and Cables. Where communications wires and cables are installed in a raceway, the raceway shall be either of a type permitted in Chapter 3 and installed in accordance with Chapter 3 or listed plenum communications raceway, listed riser communications raceway, or listed general-purpose communications raceway installed in accordance with 800.154 and installed in accordance with 362.24 through 362.56, where the requirements applicable to electrical nonmetallic tubing apply. The raceway fill tables of Chapter 3 and Chapter 9 shall not apply.

Tom, it seems to me that 800.110 does require compliance with Chapter 3. :)
 
charlie said:
800.110 Raceways for Communications Wires and Cables. Where communications wires and cables are installed in a raceway, the raceway shall be either of a type permitted in Chapter 3 and installed in accordance with Chapter 3 or listed plenum communications raceway, listed riser communications raceway, or listed general-purpose communications raceway installed in accordance with 800.154 and installed in accordance with 362.24 through 362.56, where the requirements applicable to electrical nonmetallic tubing apply. The raceway fill tables of Chapter 3 and Chapter 9 shall not apply.

Tom, it seems to me that 800.110 does require compliance with Chapter 3. :)
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I was thinking... :rolleyes:

I've seen installations where the conduit is only used as a chase (i.e. "for protection only"). As such, it ran from tray to a LV ring in the wall and had only push-on plastic bushings (POPB's) on each end of the conduit. I believe this meets Chapter 3 installation requirements without any bonding.

Of course I've also seen and installed conduit runs with POPB's or PB's at the tray end and metal wall box with conduit connector at other end. Therein lies a question as to whether the box can also be considered for protection purposes only, as the box is only required in so few situations (such as perhaps a fire-rated wall)...???
 
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If the install has to comply with chap 3 then I say 300.10, 300.11, 300.12 would be your mech, elec continuity and support. Note, that the exceptions say "short sections" need not be connected, that is up to the AHJ to decide on what "short" is.
 
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