View Full Version : Installing Utility Poles
12-05-2004, 01:50 PM
I have a need to place a couple telephone poles and do not have any information regarding the depth to which they have to be installed. Is there are standard for depth based on length of pole? Any info will be greatly appreciated. These poles are being placed in Central America and the holes have to be hand-dug.
Committee O5 on Specifications and Dimensions for Wood Poles was organized in 1924 by the Bell Telephone System and the U.S. Independent Telephone Association's American Standards Associations (ASA) Telephone Group. ATIS accepted sponsorship and secretariat responsibility for ASC O5 in 1985.
Guelph Utility Pole is one of the major suppliers of Western Red Cedar Poles
The specific depth depends upon the soil conditions (e.g., sand, clay, rocky) of the site or region. #For example, for highway testing of a 40 foot utility pole:
NCHRP Report 350 Standard (strong) Soil used a burial depth of 1.83 m (6 feet.)
National Cooperative Highway Research Program (NCHRP) Report 350 "Recommended Procedures for the Safety Performance Evaluation of Highway Features
There is the outline for Utah's DOT standards:
B. Install wood pole below grade to a minimum depth equal to one-sixth the total pole height. #Refer to AASHTO Standard Specifications for Structural Supports for Highway Signs, Luminaires, and Traffic Signals, current edition. #
C. When wood pole is installed on a slope of 2:1 or greater, increase the installation depth by 1 times the diameter of the pole (depth is to be measured from the down-slope side of the pole). # #
D. Backfill with native material in 1 foot lifts to match surrounding grade. # Tamp each lift to 90 percent compaction.
BTW, the University of Wisconsin (Madison) has the testing facilities for both utility poles and laminated wood beams.
12-05-2004, 05:35 PM
If I was trying to find this information, I'd call my local electrial company and ask a planner. Of course the earth you plan to dig may be different from your loacal area. I don't know how Central America is with codes and rules, but I'd guess the requirements are slim.
12-05-2004, 09:52 PM
and remember, better too deep than too shallow! #http://www.qrz.com/iB_html/non-cgi/emoticons/cool.gif
by the way,if they are used poles, you can usually see how deep they were buried the first time.
12-06-2004, 01:32 AM
The utility companies used to use 10 percent of the length in the ground with a minimum of 3 feet. Now it depends on the company, the type of soil, and lots of other things. But, there are still some of the "olde tymers" out there that like to use the 10 percent rule.
In the 10 years that I worked for TXU I have seen quite a number of utility poles that have gone down (from ice, wind, etc.) but I have never seen one that has just pulled up from the ground. All of those that were installed by a bonified utility company were broken off at various heights above the ground.
Of course, today, there are all sorts of regulations concerning just how a utility pole is to be installed. But, if you get out into the rural (and "backwoods") areas you will find poles that have been in place since before World War II that were installed with the 10 percent rule and that are still carrying wires. Also, along some of the rural railroad tracks there are still poles that carried the "signal wires" that are from the 1920s or even before.
However, if you follow the "rules" as set forth by the various industry organizations you can be assured that the poles will definitely meet any regulations set forth by OSHA and any other stateside organization. Thus, they should definitely meet any local standards that you may "run into".
12-06-2004, 05:34 PM
Remember utility poles in normal service help support each other, or are guyed, or both. A single utility pole not interconnected (wired) to other poles, and not guyed, isn't very self-supporting.
And the installers here don't hand-dig the holes, they use an auger on a truck to make a hole that's exactly sized to the pole, and then drop the pole in.
Amazing how fast those guys work! Around here, if a pole goes over due to a car crash, earthquake or whatever, the time from the crew arriving on site to having the new pole up is usually about one cup of coffee.
12-07-2004, 03:37 PM
Thanks a lot for all those who responded to my query. I will go with the 10% length with a minimum of 6ft depth.
There are no rules in Honduras regarding placement of utility poles and only one guy with an auger in the area who charges ridiculous prices. Two of the poles will just carry a single RG6 coax line and the third will have a 2meter vertical so not a lot of weight or wind resistance.