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RES Technical Corner

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Technical Corner

RES - Technical Corner

For the article this month lets hone in on Sunlight Resistant Cables.

Often, in solar installations, there are tracker motors that are required where there is an interest in tilting the solar panels to correspond with the sun. This aids in the amount of energy absorbed from the sun. The tracker motors can also allow the solar panels to conform to the terrain eliminating the need to level land, which reduces project cost and installation time.

So basically, there is a requirement for power cabling to be routed to the solar panels themselves and to the tracker motors.

This picture represents a scenario where there is a transition from underground cable to above ground cable supports which is quite common.

These cables will now be exposed to sunlight and the major take away from this article is that not all individual cables are sunlight resistant.

A suitable cable for the tracker motors being fed from a distribution panel board would be THHN/THWN-2 cable which is also commonly used within buildings. This cable is widely used as it is rated for dry, damp and wet conditions and covers most of the scenarios we run into except for the resistance to sunlight.

When running these cables within a conduit within a building, sunlight is not really ever an issue. However, when there is a transition as shown in the picture above, we need to be sure that we have cables that are labeled and listed as sunlight resistant.

Oddly enough it appears that only the larger cables of the THHN/THWN-2 type only carry the sunlight resistant listing. So, be mindful on some of the installations out there and let’s be sure to get the right cables installed in the environments they are listed for.

res - technical corner Hopefully this article finds you well and can be used as a reference for your project needs. If anyone would like to contribute to the Rochester Engineer and add an article or would like to request information on a specific topic (not limited to Electrical) just email Brett Eliasz at beliasz@bergmannpc.com. As always, any comments are appreciated! Thank you for reading.

Brett Eliasz, P.E., LEED AP BD+C , RES Director

NOVEMBER 2022 The ROCHESTER ENGINEER | 7

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