How To Ground a Solar Thermal Collector Array

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Like any expensive equipment containing lots of metal and liquid, a solar thermal collector array needs to be grounded. Collectors can act like huge static electricity absorbers, gathering charge from nearby lightning strikes and passing it along all the copper pipes to the controller (in an AC system). One big power surge and your controller goes pop!

Even if you're running a DC system powered by a PV panel, you should still ground the collector array to avoid electrical charge being stored in your pipes.

The best way to ground your array is to place a stainless steel screw on each collector. Take one long strand of #6 bare, stranded copper wire and separate the strands; wrap the strands around the first screw and tighten it to hold the wire against the collector. If your collectors are painted, you should scrape the paint off around the screw to give a metal-to-metal connection.

Take the wire strand and lead it to the next collector, separate the strands, wrap them around the screw and tighten it into place. Do this across the entire collector array, using a single strand of bare wire to electrically bond all the collectors together.

Next, bond the same wire strand to the copper piping using a stainless steel hose clamp. Finally, run the wire to the building's grounding rod and attach it to complete the grounding circuit. You should not add a second rod just for the collector array, but use the common rod for the whole building.