Crossing transmission line

[cuky2000]

It is allow to cross a 345 kV existing line entrance to a substation with a 138 kV line above?
The 345 kV is transitioning from a vertical arrangement in a pole to an H frame on the substation entrance. The only space free is from above the existing 345 kV line. Underground is also crowded.

 

[cranky108]

Typically the lower voltage will be below.
Maybe rase the 345kV.

 

[Mbrooke]

I don't know of anything stopping you, but typically as mentioned higher voltages go on top.

 

[bacon4life]

I have never seen a specific prohibition against having the lower voltage line on the top. A couple of things to think about:
1) The overall structure has to be taller if the larger voltage is on the bottom. At a substation entrance, the cost for the added height of the slightly taller 138 kV structure might be trivial compared to raising the 345 kV line.
2) Maintenance activities on the upper circuit may impact the lower circuit if a conductor is broken/dropped. De-energizing the lower 345 kV line for maintenance on the upper 138 kV may be necessary. Future maintenance folks will grumble about this arrangement.