Hot Stick Lengths and Voltage Ratings for Live Line Work

[111R]

What is typically used to determine the length of hot sticks for live line work? I'm accustomed to seeing hot sticks in excess of 25' being used for voltages as low as 138kV. Some of this is simply due to the height of the transmission lines from ground level.

OSHA 1926.950 shows minimum clearances of 3'-6" for 138kV:

https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=10821

While I understand that a hot stick tested per ASTM F711 should not flash over at this distance, I doubt that any live line workers would want to come near this distance to a 138kV energized line.

Is there another rule of thumb that is typically used for approach distances when selecting hot sticks for use in the field?

Thanks

 

[mgtrp]

On the long hot sticks, only a relatively small section is the "insulating section" (dependent on voltage class of the stick). The remainder is simply for the convenience of the user.

 

[Jebb]

Take a look at the National Electric Safety Code C2-2012 Section 441 and Table 441-1. Also IEEE 516-2003 Guide for Maint. Methods for Energized Power Lines. The "extra" length is due where the worker has to be positioned for the work (i.e. standing on the ground in a substation or reaching from a tower along a transmission line).

 

[crshears]

On the long hot sticks, only a relatively small section is the "insulating section" (dependent on voltage class of the stick). The remainder is simply for the convenience of the user.

The long sticks I used were of one kind of material for their entire length, so if there was in fact an 'insulating section' there it was completely indistinguishable from the rest of the stick. There was also a decal on the sticks with text saying something about them being rated, tested and certified to withstand 100 kV per meter, which theoretically meant we could have used the 25-foot ones on our 500 kV equipment with no problem at all, not that we had any manually operated equipment at that voltage level.

CR