fire alarms

[om]

what is the burial depth of a 24volt fire alarm direct burial cable? In the nec 2002 artical # 300.5 column 1 (all locations not specified below) states 24" but in the nfpa 72 1999 artical #6-8.2.2.6 its states 18".

[dacreman]

The local code or AHJ in your area may specify. 24" is what I was told by an inspector some time ago and I have kept with that.