What tightening torque should be used for a hexagonal head screw (not split-bolt) on a 250 kcmil conductor?

325 inches-pounds

Explanation:

Tightening technique guide suggests that;

4/0 kcmil ---requires---→250 in-pounds tightening torque with 500 split-bolt

250kcmil ---requires---→325 in-pounds tightening torque with 650 split-bolt

300kcmil ---requires---→325 in-pounds tightening torque with 650 split-bolt

350kcmil ---requires---→325 in-pounds tightening torque with 650 split-bolt

400kcmil ---requires---→325 in-pounds tightening torque with 825 split-bolt

b.

explanation:

the ima (higher than 1m) will be greater than the ima with the height of 1m.