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Nope, I am not a Lineman. I'm an Inside wireman. The whole 12KV system is owned by the airport not the PoCo. The meter is in a 66KV substation down the road a bit.

It's always a lot of fun when we inside guys start messing with Medium Voltage. I wish I had more experience with it.

Keep your hot gloves handy,
Doc

A couple of months ago a team of workmen repairing a road surface nearby hit a tel. cable and took out all the phones in my settlement.

Some years ago I recall hearing about a team of outside contractors working at Goonhilly (big telecoms satellite station in England) who went into an underground 11kV feeder, though fortunately it was isolated at the time. When hauled before the boss, apparently the "head digger" said he saw the bright yellow and black marker tape "Danger: Electric cables below") but didn't think it mattered!

For underground service conductors only [not for feeders or branch circuits] up to 600 volts when not encased in concrete and buried 18 inches or more below grade, are required to have their location identified by a "warning ribbon" that is placed in the trench at least 12 inches above the underground installation. 300.5(D)(3)

No ribbon is required for feeders and branch circuits because they contain short-circuit and overload protection.

Table 300.50 for over 600 volts ......

Exception No. 3: The minimum cover requirements do not apply to conduits or other raceways that are located under a building or exterior concrete slab not less than 4 inches in thickness that extends not less than 6 inches beyond the underground installation.

A warning ribbon "or other effective means suitable for the conditions" must be placed above the underground installation.



[This message has been edited by Joe Tedesco (edited 10-20-2002).]