What clamp should I used if I have multi thickness panels?

[electrofelon]

Do you have any pictures of your self built racking?

This isn't a very good picture but it's the only one I can find at the moment. The rails are aluminum Z channel. Panels are attached thru the bottom flange of the frame with hardware.

 

[letgomywago]

This isn't a very good picture but it's the only one I can find at the moment. The rails are aluminum Z channel. Panels are attached thru the bottom flange of the frame with hardware.

Cool that would be easier to swap out with the various future products that could be needed. It also is nice that it's a non ferrous method still.

 

[pv_n00b]

That would be fine. There is nothing in the NEC requiring the panel mounting hardware and materials be "listed" or "listed for the purpose". My partner and I build our own ground mount racking system. The only thing with some sort of "home brew" setup is the bonding - you would need to bond each module or use a WEEB.

There is if the mounting hardware is also the EGC.

690.43(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.

Can't use WEEBs to bond the module to the racking expecting the racking to be the EGC unless the racking is 2703 listed. You can still run a wire EGC lugged to each module, old school still works.

 

[electrofelon]

There is if the mounting hardware is also the EGC.


Can't use WEEBs to bond the module to the racking expecting the racking to be the EGC unless the racking is 2703 listed. You can still run a wire EGC lugged to each module, old school still works.

The way I read that it is because the rails are not listed for grounding that makes a WEEB required. In other words, I see the concern being the rail/module interface, not the rail being a EGC. I do see how a more strict reading would disallow even using the rail as an EGC at all. That said this has been approved by the inspectors and the additional review and inspection by the state agency tjat provides incentives.

 

[jaggedben]

The way I read that it is because the rails are not listed for grounding that makes a WEEB required. ...

I agree with pv_noob. The whole WEEB thing without listing predated the code section he quotes. Nowadays bonding the module to the racking to provide grounding is only allowed if it's all listed. Otherwise you must bond the module directly to a wire EGC according to module instructions. Lay-on lug or whatever.

 

[pv_n00b]

The way I read that it is because the rails are not listed for grounding that makes a WEEB required. In other words, I see the concern being the rail/module interface, not the rail being a EGC. I do see how a more strict reading would disallow even using the rail as an EGC at all. That said this has been approved by the inspectors and the additional review and inspection by the state agency tjat provides incentives.

In the olden days, we bonded the modules to a wire EGC, bonded the wire EGC to the various parts of the rack, then took that wire EGC and bonded it to the inverter ground connection. That was bonding and we liked it.
Then the WEEB came along and the need to bond the module to the racking was done by the WEEB and the bonding of the racking together and to the inverter ground was done by a wire EGC. But racking was a collection of parts that were bolted together and those connections were not evaluated as electrical bonds. So all the parts of the racking still needed a connection to a wired EGC. The introduction of UL 2703 allowed the racking and all its connections to be listed as an EGC, so then you just had to connect one point on the racking to the inverter with a wire EGC. After the introduction of UL 2703 the use of WEEBs to connect modules to unlisted racking was no longer allowed.
You can still use unlisted racking, but you are back to the old school method of connecting all the parts together with a wire EGC.
Just because an AHJ does not reject the work does not certify that the work is code compliant, nor does one AHJ's acceptance then require another AHJs to accept it.

 

[electrofelon]

I agree with pv_noob. The whole WEEB thing without listing predated the code section he quotes. Nowadays bonding the module to the racking to provide grounding is only allowed if it's all listed. Otherwise you must bond the module directly to a wire EGC according to module instructions. Lay-on lug or whatever.

In the olden days, we bonded the modules to a wire EGC, bonded the wire EGC to the various parts of the rack, then took that wire EGC and bonded it to the inverter ground connection. That was bonding and we liked it.
Then the WEEB came along and the need to bond the module to the racking was done by the WEEB and the bonding of the racking together and to the inverter ground was done by a wire EGC. But racking was a collection of parts that were bolted together and those connections were not evaluated as electrical bonds. So all the parts of the racking still needed a connection to a wired EGC. The introduction of UL 2703 allowed the racking and all its connections to be listed as an EGC, so then you just had to connect one point on the racking to the inverter with a wire EGC. After the introduction of UL 2703 the use of WEEBs to connect modules to unlisted racking was no longer allowed.
You can still use unlisted racking, but you are back to the old school method of connecting all the parts together with a wire EGC.
Just because an AHJ does not reject the work does not certify that the work is code compliant, nor does one AHJ's acceptance then require another AHJs to accept it.

My AHJ and state agency that reviews plans and provide incentives consider the "mounting device" in 690.43 to be a WEEB, and that's fine by me