Fiberglass Crossarm “Pentech Washer:
More than Just a Washer!
The MacLean Power Systems “Pentech” washer is an innovative and patented product that provides superior load distribution performance across fiberglass crossarm deadends. Fiberglass crossarm deadends are structural devices used to support and terminate conductors on overhead distribution circuits. In traditional line construction, overhead lines are designed with a working load or anticipated maximum design tension. Under real world applications and changing environmental conditions such as wind, ice, and sag changes, load distribution across the surface of the crossarm vary. The typical fiberglass deadend connection utilizes a double arming bolt through the fiberglass crossarm. At each end of the double arming bolt a flat washer and eye nut are assembled. As the eye nut is tightened down, the flat washer rests against the side of the crossarm. The eye nuts provide a means for a deadend insulator to be attached to the crossarm. The purpose of the flat washer is to provide bearing support against the crossarm under load. Installation using a flat washer design becomes critical and requires the flat washer edges to be parallel with the tube top surface (Figure 1). This provides support across section A of Figure 2 with a majority of the load across the hollow cavity wall section B of Figure 2. If the flat washer is not perfectly parallel with the tube top surface, the cavity wall will bear more of the load being supported. Loading changes over time may weaken the cavity wall creating the potential possibility for the hardware to pull through the crossarm if not properly installed. Only the Pentech washer can ensure full contact and arm strength. The washer is designed to securely wrap around the surface of the crossarm distributing tension loads to the outer edges of the crossarm (Figure 3). This distribution of loads to the crossarm edges helps concentrate the loads where the maximum material thickness exists rather than on the hollow cavity wall of the tube. This design alleviates the pressure imposed on the tube cavity to eliminate crushing or collapsing.
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