Grill The Fire Expert

Oct. 27, 2008
Digging For An Answer To Underground Cable

Q: As a follow up to last month’s questions on Power-Limited Fire Alarm Cables (FPL), is there a requirement to use FPL in conduit that is installed underground from one building to another building? The Authority Having Jurisdiction (AHJ) says I always have to use “fire alarm cable.”

A: No. Type FPL is meant to be installed exposed in a building, and when following the rules from Article 760.15, Part B, conduit isn’t necessary. To be given the FPL designation is to indicate that the conductor’s insulation/jacket will be “resistant to the spread of fire,” which is not a factor with buried cable.
Therefore, since FPL is not approved for “wet locations” and there is no such thing as “direct burial FPL cable,” you are left with choosing one of three methods. Which method you choose will probably depend on how much you like to dig:

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Greg Kessinger, SET, CFPS, president of an alarm installing company since 1981, teaches NICET training classes to fire alarm system designers and installers and continuing education seminars for Ohio’s fire alarm inspectors. You can reach him at 888-910-2272; e-mail: [email protected]; or visit his website at