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Joined: Dec 2001
Posts: 4
OP
Junior Member
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A college campus installation starts at a utility owned pole, customer owned 7200V underground conductors run to a customer owned padmounted 7200V switch and fuse, from there 7200V conductors loop to a series of padmount transformers, each feeding a seperate building.
Question: Are the 7200V underground conductors from the switch to the padmount transformers, a feeder or service conductors? Do they require an underground warning ribbon?
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Joined: Oct 2000
Posts: 2,749
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See the 1999 NEC, Table 300-50, Exception No. 3 for underground installations over 600 volts.
...... A warning ribbon or other effective means suitable for the conditions shall be placed above the underground installation.
Joe Tedesco, NEC Consultant
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Joined: Dec 2001
Posts: 4
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Joe,
Table 300-50 Exception No.3 only applies to conduits & raceways that are "under a building or exterior slab" This exception waives the minimum cover requirements. My installation is not under a building or exterior slab, it is direct burial conductors not "conduits or other raceways", and mine are buried according to the minimum cover requirements. Exception #3 doesn't apply in my case.
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Joined: Aug 2001
Posts: 7,520
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At a telecoms facility where I worked some years ago, some outside contractors nearly put a JCB digger shovel into a buried 11kV cable.
It was only the hatched black/yellow warning tape that alerted a manager to what was about to happen. The digger crew intended to carry on through the tape (more Darwin Award candidates?) but the boss saw the tape in time to stop them.
Warning tape is cheap. I'd use it.
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Posts: 264
Joined: February 2013
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