Overhead Electric Line Failure - Clearances

[nhcf]

I have a design requirement for process storage tank that it shall not be located where exposed to failure of overhead electric power lines operating at more than 600V.

Is there a rule of thumb regarding clearance distances from an OH distribution or transmission line where the tank would no longer be exposed? For instance, would it be based on pole/tower height? A percentage of conductor span between poles/towers? NESC or IEEE guidance? Something else?

 

[krisys]

I guess there would be some API Standards. If you have access please check API.

 

[bacon4life]

Placing the tank outside the falling radius would limit the potential for direct physical damage. Electrical damage will be harder to absolutely prevent. Overhead conductors falling on top of communication messenger wires or metal fences can result in damage hundreds of feet away from the failed overhead line.

 

[7anoter4]

NESC C2-2007?
Rule 234 C. Clearances of wires, conductors, cables, and rigid live parts from buildings, signs, billboards, chimneys, radio and television antennas, tanks, and other installations except bridges

 

[ds94]

Another good reference is the safe limits of approach.

It can't hurt to determine the voltages of any distribution/transmission lines that are near the tank, and then check their safe limits of approach. Assume unqualified personnel to be conservative.

It may vary depending on where in the world you are, but the general rule of thumb is: "If you don't know the voltage, stay 20 feet away".