Overhead Wires, required height.

[wallager]

I am getting a lot of claims where tractor trailers are catching overhead wires on public roads, can anyone tell me where to find the nec reg on overhead wire required height ? I've found references to it but would like to know just what and where the reg is. Thanks

 

[don_resqcapt19]

The NEC does not apply to utility conductors over public roads.
Don

 

[jtester]

The NESC generally applies to utility owned overhead lines.

Jim T

 

[zog]

Off the top of my head I think the rule is 10 ft up to 50kV and 4" more for every 10kV above 50kV.

This distance applys to vehicle clearances (OSHA 1910.269) so I would assume the road has a max height allowance for the vehicles based on bridge clearances so add the required clearance distances to the max allowable vehicle height.

Again, I am not sure on how this rule would apply to roads, but it does apply to substations. Anyone else have more on this?

 

[don_resqcapt19]

zog,
That won't work for roads as trucks can be 13'6" without any special permits. I think the mimium road clearance is 18'6', but an not sure. That would match up with Table 225.60 in the NEC.
Don

 

[zog]

Did you read my whole post? I said add that rule to the max allowable vehicle height.

 

[don_resqcapt19]

Did you read my whole post?

no

 

[jtester]

The 2003 NESC specifies 15'6" above roads and streets to insulated communications conductors as a general rule. There is an exception for crossing over driveways not subject to truck traffic.


Jim T