Can you provide more information?
Is this an NEC question, or utility related? Different standards apply.
What do you mean by between two poles? Are you referring to the minimum spacing out in a span?
Which line is on top? There are different requirements if the communications is on the top than if the power is on top.
For example, NESC Table 233-1, which applies to lines on different structures, but adjacent, requires 2' from insulated secondaries or grounded neutrals down to communications conductors. It requires 4' if the wires are reversed. Power is almost always on top, but not every time.
Table 235-5 applies to wires on ths same structure at supports, and requires 40" as a general rule.
Jim T
edited to include reference to 235-5
