The ANSI O5.1 document defines the size and class of wood poles.  The document stipulates the sizes of wood poles such that their average strengths meet set class loading values.  In other words, 50% of poles will be stronger than the class value and 50% of the poles will be weaker than the class value. 

ANSI O5.1 does not provide any information on the deflection of wood poles under class loads.  Deflection of poles becomes important in areas where mandated electrical clearances need to be maintained for safety.  PLS-CADD does provide deflection information when wood poles are subjected to loads.  However, those deflections are average deflections for that particular size and class of pole.  Since these are average values, additional margins need to be considered to ensure that safety clearances can be maintained.  Typically, this would be done by installing a larger pole than what is required for strength.

Like all manufactured poles, the strength and deflection of the EndruaPOLE is based on reliability-based design concepts.  In this concept, the 5% Lower Exclusion Limit (5% LEL) is used to class poles based on strength and deflection.  What does this mean?  By using the 5% LEL values, 95% of the time the EnduraPOLE will be stronger than its rated class load and 95% of the time the deflection of the EnduraPOLE will be less than the rated class deflection.

Thus, when selecting the EnduraPOLE, the pole will have the capacity to carry its design loads and more – ensuring system reliability under extreme weather events.  Also, its deflection will not encroach on any mandated safety clearances.  With the EnduraPOLE engineers will know how the pole will perform under the design loads rather than having to add margins to ensure that a wood pole will perform under its design loads.  With the EnduraPOLE™ engineers will sleep better at night.  Isn’t that what we all want?

Talk with an engineer about how EnduraPOLE deflection behavior aligns with your clearance and modeling assumptions.