Racking not UL listed

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jjavier

Member
Location
Maine
We have an aluminium racking for solar panels on a roof. This racking is no UL listed. Can we ground power optimizers os solaredge and panels with star washer or do we need use a copper cable? I am not sure that I can use this structrure as egc because is not UL listed. Is it a requirement a solar racking (aluminium structure) UL listed?
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
My reading of the code is that your bonding connections just need to be 'identified bonding jumpers', not listed.

690.43(C) from the 2014 NEC.

C) Structure as Equipment Grounding Conductor.
Devices listed and identified for grounding the metallic
frames of PV modules or other equipment shall be
permitted to bond the exposed metal surfaces or other
equipment to mounting structures. Metallic mounting
structures, other than building steel, used for grounding
purposes shall be identified as equipment-grounding
conductors or shall have identified bonding jumpers or
devices connected between the separate metallic sections
and shall be bonded to the grounding system.

With that said, I'd not really want to have an argument with an inspector over whether a star washer is an 'identified' bonding jumper. If you just order some stainless washers from a hardware supply, it's arguably not identified. Unless it is supplied by the manufacturer (e.g. starwasher comes with SolarEdge optimizer), I'd use something listed or at least specifically designed to make bonding connections. WEEBs, for example. In fact I wouldn't use a racking that didn't have a WEEB made for bonding the modules. And I'd use copper-tinned direct burial lugs for everything else.

Another thing is that, especially if you're not using clamps or WEEBs that are listed for bonding the modules, arguably you'll have to use a method for grounding the modules that is described in the module installation manual. Otherwise you're violating 110.3(B) by not following the instructions for the listed equipment.

I hasten to add: Grounding features on solar racking have really matured industry wide and finding affordable racking with listed grounding features is not difficult these days.
 

pv_n00b

Senior Member
Location
CA, USA
This is the 2014 NEC:

(C) Structure as Equipment Grounding Conductor. Devices
listed and identified for grounding the metallic frames
of PV modules or other equipment shall be permitted to
bond the exposed metal surfaces or other equipment to
mounting structures. Metallic mounting structures, other
than building steel, used for grounding purposes shall be
identified as equipment-grounding conductors or shall have
identified bonding jumpers or devices connected between
the separate metallic sections and shall be bonded to the
grounding system.

This is 2017:

(A) Photovoltaic Module Mounting Systems and Devices.
Devices and systems used for mounting PV modules that are
also used for bonding module frames shall be listed, labeled,
and identified for bonding PV modules. Devices that mount
adjacent PV modules shall be permitted to bond adjacent
PV modules.

I think someone would be hard pressed to convince an AHJ that a mounting system is identified for use as an EGC without being listed under the 2014 NEC. Under 2017 listing is now required. Many people feel that “identified” means that the manufacturer just says it okay to use it but the NEC definition requires a higher standard. A third party evaluation is still required but it does not need to be done by listing, although listing is considered identifying. So think of it as listing lite.

Identified (as applied to equipment). Recognizable as
suitable for the specific purpose, function, use, environment,
application, and so forth, where described in a particular
Code requirement.
Informational Note: Some examples of ways to determine
suitability of equipment for a specific purpose, environment,
or application include investigations by a qualified
testing laboratory (listing and labeling), an inspection
agency, or other organizations concerned with product
evaluation.

So where does that leave you? Probably running a copper EGC to all the equipment and not depending on the rack.
 

jjavier

Member
Location
Maine
ul 1703

ul 1703

There is a new UL1703, for rack systems. Do my rack system must to be listed?
I understand that if a want to ground my panels with a UL ground washer, but the rack system is not UL, probably we will have problems with AHJ. Is that correct?

Regards
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
There is a new UL1703, for rack systems. Do my rack system must to be listed?
I understand that if a want to ground my panels with a UL ground washer, but the rack system is not UL, probably we will have problems with AHJ. Is that correct?

Regards

As has been pointed out, it depends a lot on which code cycle is being enforced. I think it can be safely said that the fewer components are listed, the more likely you'll have problems. Maybe share specifics if you want more specific feedback.
 

pv_n00b

Senior Member
Location
CA, USA
As far as the 2017 NEC is concerned the mounting system only needs to be listed if you want to use it as the EGC. If you use an unlisted mounting system then you just have to run an EGC conductor through the array. In 2014 and 2011 it required the mounting system to be identified for use as an EGC, which for all practical purposes means listed.

The main issue with using a mounting system as the EGC is having good long term electrical bonds where the components are mechanically connected.
 
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jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
As far as the 2017 NEC is concerned the mounting system only needs to be listed if you want to use it as the EGC. If you use an unlisted mounting system then you just have to run an EGC conductor through the array. In 2014 and 2011 it required the mounting system to be identified for use as an EGC, which for all practical purposes means listed.

Not sure where you're getting that. I think it just says the mounting system has to be identified if "used for grounding purposes." One can still choose to not use the mounting system for grounding purposes, and to run a copper EGC and put tinned-copper lay-in lugs on all the modules and everything else. But the bottom line is that this is less economical than using racking that has listed and identified grounding components.
 
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