Panel grounding using Unirac rails?

A friend of mine is helping someone install a solar system. They are using a Unirac system for mounting the panels. I asked if he was going to use the special ground lugs on each panel. He said that the Unirac system has a piece of hardware that digs into the panel frame and uses that and the rail for a ground conductor. The rail will be grounded.

I didn’t think this was NEC code compliant. I did a quick search here but I still am unsure.:confused:


  • newenergynewenergy Solar Expert Posts: 291 ✭✭✭✭✭✭
    Re: Panel grounding using Unirac rails?

    There are two such products that I know about that work for Unirac. They make their own grounding clips and Wiley Electronics makes the Weeb clips.

    They are NEC compliant, imho. Not that they aren't allowed by the 2005 NEC, but the 2008 NEC specifically states:

    690.43 Equipment Grounding


    Devices listed and identified for grounding the metallic frames of PV modules shall be permitted to bond the exposed metallic frames of PV modules to grounded mounting structures. Devices listed and identified for grounding the metallic frames of PV modules shall be permitted to bond the exposed metallic frames of PV modules to the metallic frames of adjacent PV modules.

    Some people, and some module manufacturers have a problem with them not being UL listed, but they are ETL listed, which is a recognized listing lab.


    Also, Unirac makes a grounding lug and a grounding clip and they are different parts. The lug fits into the top rail slot. It has a lug that takes a wire and where it hits the rail it has a thin stainless steel shim with protrusions that dig into the rail.
  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: Panel grounding using Unirac rails?

    I believe there was a US Federal law that made NRTL (Nationally Recongnized Testing Laboratories) the proper term for a Listing Agency... UL used to be written into building codes from the days when UL was virtually the only listing agency for commercial electrical appliances/components.

    From here:
    NRTL’s are qualified private organizations that meet the requirements of the OSHA regulations. The NRTLs perform independent safety testing and product certification. Each NRTL must meet the requirements as set for by OSHA in the NRTL program. NRTLs may be based in the USA or in other countries. A listing of current NRTLs may be found at the OSHA web site. The OSHA recognition process is the same for all organizations.

    A NRTL performs several functions one of which is to provide safety testing on equipment. The safety testing by the NRTL will ensure that a representative unit of a particular product has met all the necessary safety features. The NRTL must also organize and operate a product certification program that includes listing, labeling, and follow-up programs. The NRTL must make sure that all manufactured units of a particular product have all the required safety features as was initially tested. It should be noted that OSHA does not perform any product approvals but relies on NRTLs to do this work.
    Each NRTL has a scope of accreditation, which will vary between NTRLs. The scope of accreditation is available from the OSHA web page. The NRTL must test and use a US based test standard that is development and maintained by a USA standards developing organization. International test standards may be used if they have been harmonized to USA requirements by a USA standards developing organization. NRTLs have been recognized for more than 600 product safety standards....
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
Sign In or Register to comment.