NEC in the Facility, March 22, 2011

March 22, 2011
You can't just poke a hole in your building's envelope and run broadband cable through it. First, you must assess the circuit power level per Table 830.15

You can't just poke a hole in your building's envelope and run broadband cable through it. First, you must assess the circuit power level per Table 830.15 to determine if it's low power or medium power. For low-power circuits, run cable that is type BMU, BM, or BMR. For medium-power circuits, run type BLU or BLX [830.40].

What if the utility-supplied cable doesn't match what you need to run? In that case, you'll need to build and install an interface box on the outside of the building, and connect the different cables inside that box. An interface box is generally advisable anyhow, so you can separate utility cabling from premises wiring outside the building rather than running utility cabling into your building. If the utility needs to replace its cabling, utility technicians won't need to enter your building to do so.

A common problem with broadband cabling is it's grounded instead of bonded. That is, the cable shields tie to a local ground rod. This does nothing for you. In our next issue, we'll see how to fix this problem.

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