Common Practices for Grounding Solar PV Panels

What we know as the “Ilsco Lug” is perhaps the first grounding lug certified by UL and approved for use in solar electric systems. Therefore you can imagine that it is commonly specified in installation manuals for solar equipment particularly for PV panels. In 2013 Ilsco grounding lugs received UL certification under UL2703 standard.

The Ilsco GBL-4DBT grounding lug meets all the code requirement to be used in solar PV installations, and they have been extensively used in small and large systems. The GBL-4DBT is made of copper and it is tin plated for extra resistance to corrosion; the lug comes with a stainless steel hex screw to secure the grounding conductor, and a 10-32 thread forming screw & lock-tooth washer to create a solid bonding connection between the lug and the anodized aluminum frame of the solar panel. It is rated for direct burial and outdoor exposed use. We could say that the Ilsco GBL-4DBT set the standard for future grounding options. An equivalent to the Ilsco, with the same specifications, is the Burndy CL501TN grounding lug.

Ilsco GBL-4DBT Grounding Lug
Ilsco GBL-4DBT Grounding Lug

Another lug that has been broadly used in PV installation is the Tyco Solklip. It is approved for UL467 requirements and certified under UL1703 standards. The main feature of the Solklip is that the grounding conductor is clipped to the lug rather than screwed in; this significantly reduces installation time especially in larger PV systems. The Solklip can be attached to the aluminum frame of the solar panel using a #10-32 tread cutting screw (part no. 1954381-1) or a #8-32 pan-head screw and nut (part no. 1954381-2).

Tyco Electronics Solklip
Tyco Electronics Solklip

A more recent practice is to use Wiley WEEB lugs, most likely because they are very versatile in how they can be installed. They require one solid or stranded copper wire (14 AWG to 6 AWG) or two copper wires (12 AWG to 10 AWG). The WEEB lugs create one continuous ground with minimal tools and preparation, and they eliminate the need to prepare the surface of the rail or PV module prior to installation. They are made of tin-plated copper. They are available with or without WEEB washers and/or installation hardware, and they can come assembled or unassembled. All WEEB lugs are ETL listed to ANSI/UL 467. CSA certified to C22.2 No.41.

Wiley Grounding Lug with WEEB Washer
Wiley Grounding Lug with WEEB Washer

Commonly used WEEB lugs:
Dimensions: LWH 1.60” x 0.71” x 0.47”
Hole 0.266”
Hardware: 1/4″

Dimensions: LWH 1.60” x 0.87” x 0.47”
Hole 0.323”
Hardware: 5/16″