Electricity Today T&D Magazine

Introduction

In 2007, the National Electric Safety Code (NESC) standards committee adopted composite poles, crossarms, and braces into the code. This action was significant in mandating the composite electrical structures manufacturing industry to publish their design strength values to a 5% Lower Exclusion Limit (LEL). We published a white paper that creates transparency for the utility engineer, in that it describes the test methods, test setup, statistical calculations and relevant standards utilized to generate 5th percentile design strength values for Creative Pultrusions, Inc. (CPI) CP2500 series crossarm. The following is an abbreviated version of that white paper. You can find the complete writing on our website under Technical Papers.

Investigation

The following mechanical characteristics were evaluated to obtain the 5th percentile strength values for design, standards development, and quality control purposes:
Bending Strength at Failure for Deadend and Tangent Crossarm
In-plane Shear Strength at Failure
Flexural Modulus of Elasticity

Experiment

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