This may or may not be an NEC question, but here goes.
We started work on something completely new for everyone on the job today- repair of transmission and distribution lines across an oilfield. Acres and acres and acres of oilfield.
We're setting poles, and ran into something none of us could agree on exactly what to do about. I don't know how many journeyman-years of experience we had on this project today, but there were four JM and five apprentices (and company trucks everywhere...) and we're all figuring out "the hard way," so to speak. At least we have the right equipment for the job- pole trucks, trailer, double-bucket trucks, skid loader, etc. Today's lesson: build the crossbar on the pole before the pole is in the air.
Poco delivers metered service to the edge of the property at 13,200v, it's a three-wire ungrounded delta primary. That runs all over the place, on our poles (28 of which are broken in two and lying on the ground) .
We step that down, in various locations, to 3? 480v (still ungrounded), which eventually drops off the poles, to disconnects, then to motor starters, then to motors mounted on the wells. All of the well motors are 480v 3?.
The poles we're setting have AL coiled at the bottom and running up the side. The first question came up here. What are we supposed to do with this wire? We're stringing two ungrounded systems on these poles. There's nothing to connect a grounded/ing conductor to.
The next question comes in relation to the two systems. The 13,200 is being run at the top of the poles (35' poles). The 480 distribution, when present, is run below that on the same poles. Where can I find the minimum allowable clearance between these two systems? Where can I find the minimum allowable clearance between two legs of the 13,200 system? What book should I be looking in?
We can always go by "what's already been done out there" but I'd like to see some sort of reference work on the matter. I can't find anything in the NEC that applies, but I'm happy to hear your thoughts.
By the way- I've noticed that there is a ground rod (or two) at every well, and the equipment is grounded to that, from the well disconnect 'forward'.
PS: There is no AHJ in play here. (hint) So don't bother to include "check with the local AHJ" in the list of what to do next.
TIA
We started work on something completely new for everyone on the job today- repair of transmission and distribution lines across an oilfield. Acres and acres and acres of oilfield.
We're setting poles, and ran into something none of us could agree on exactly what to do about. I don't know how many journeyman-years of experience we had on this project today, but there were four JM and five apprentices (and company trucks everywhere...) and we're all figuring out "the hard way," so to speak. At least we have the right equipment for the job- pole trucks, trailer, double-bucket trucks, skid loader, etc. Today's lesson: build the crossbar on the pole before the pole is in the air.
Poco delivers metered service to the edge of the property at 13,200v, it's a three-wire ungrounded delta primary. That runs all over the place, on our poles (28 of which are broken in two and lying on the ground) .
We step that down, in various locations, to 3? 480v (still ungrounded), which eventually drops off the poles, to disconnects, then to motor starters, then to motors mounted on the wells. All of the well motors are 480v 3?.
The poles we're setting have AL coiled at the bottom and running up the side. The first question came up here. What are we supposed to do with this wire? We're stringing two ungrounded systems on these poles. There's nothing to connect a grounded/ing conductor to.
The next question comes in relation to the two systems. The 13,200 is being run at the top of the poles (35' poles). The 480 distribution, when present, is run below that on the same poles. Where can I find the minimum allowable clearance between these two systems? Where can I find the minimum allowable clearance between two legs of the 13,200 system? What book should I be looking in?
We can always go by "what's already been done out there" but I'd like to see some sort of reference work on the matter. I can't find anything in the NEC that applies, but I'm happy to hear your thoughts.
By the way- I've noticed that there is a ground rod (or two) at every well, and the equipment is grounded to that, from the well disconnect 'forward'.
PS: There is no AHJ in play here. (hint) So don't bother to include "check with the local AHJ" in the list of what to do next.
TIA
