Avoid feeling tapped out when trying to apply feeder tap rules
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Assume I have a 2000A [480v 3ph] breaker feeding a bunch of cables. I attach 3-#24 wires and run for 15,000.0 Ft and termintate at a 1 amp disconnect w/ fuse. [I am assuming a #24 wire is rated for 1 amp] This seems to meet 240 21 B 5.
So, the size of the tap wire can be any size?
I can run 24AWG for 15,000 ft or farther and terminate at a 1amp fuse w/ disconnect mounted outside fed from a 2000A breaker? Really??
I work in the drilling industry where things have been out of code for years and making them so is a constant battle. I recently ran into the following situation:
I discovered 3 devices with electric motors drawing between 12 full load amps and 25 full load amps. Each device has a starter with overloads for motor protection that I assume are sized correctly. Two of the devices are fed with a 4 conductor #10 cable and the third is fed with a 4 conductor #8 cable. These three devices were plugged into two 100 amp service disconnect receptacles and one 60 amp service disconnect receptacle. I told the drilling supervisor that we couldn't continue to run the devices from these disconnects as the device feeder cables were only rated to just over 30 amps. I reran these device feeders so they were fed from 30 amp breakers and one 50 amp breaker(that I turned the trip setting down to 60% getting it below the rated amp level of the feeder cable). The circuits all all 3 phase 480 volt power. A fellow electrician told me it was fine the way it was before because of the starters and overloads. Is he correct? What does the code say about this?
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