Line Side Tap

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electro7

Senior Member
Location
Northern CA, US
Occupation
Electrician, Solar and Electrical Contractor
Hi,

I am looking at a few commercial solar systems that are requiring a line side tap for their interconnections. I am wondering if others are getting UL involved if the AHJ does not mention anything about it or seemed concerned with it?

What kind of liability would fall on me as the electrical contractor if something were to happen and I did not get the line side tap UL listed?

I am working with an electrical engineering firm on one in which they have not mentioned or seem concerned about getting UL involved.

Thanks!
 
Just to get this out of the way: I assume you are talking specifically about a line side connection to a busbar in a switchboard? There are many ways to make a line side connection that wouldnt require (potentially/arguably) modifying listed equipment.

Personally, I would have no problem making a connection to a switchboard buss by adding or changing lugs without a field eval if the AHJ didnt require it.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
...

What kind of liability would fall on me as the electrical contractor if something were to happen and I did not get the line side tap UL listed?
...

I think getting it listed actually does relatively little to reduce your liability. There's liability regardless, and once lawyers and expert witnessness get involved... You'd be in trouble if someone could show that you didn't follow industry standard, or especially if you didn't follow the same standard when an AHJ didn't require listing as when they did. It might come down to how smart an expert witness the opposing insurance company can muster.

Field listing isn't really required if you are doing something that the equipment instructions or labels allow.
 
Also note that, despite it often being said, you dont really "void a listing." Here is a statement from an article by UL: https://www.ul.com/wp-content/uploads/2014/04/ul_TappingBusbarConsiderations1.pdf

It is the responsibility of the code authority to first
determine whether a modification is acceptable or
significant enough to require one of UL’s Field Engineering
Services staff members to evaluate the modified product.

Then see NEC 90.4

Personally, I dont worry about liability from my electrical jobs. I have an LLC for liability protection, and am much more concerned about driving on the roads with everyone texting while driving.......
 

pv_n00b

Senior Member
Location
CA, USA
Also note that, despite it often being said, you dont really "void a listing." Here is a statement from an article by UL: https://www.ul.com/wp-content/uploads/2014/04/ul_TappingBusbarConsiderations1.pdf



Then see NEC 90.4

Personally, I dont worry about liability from my electrical jobs. I have an LLC for liability protection, and am much more concerned about driving on the roads with everyone texting while driving.......



From the document you reference:
"When a UL Listed product is modified after it leaves the manufacturing facility, UL has no way to determine if it continues to comply with the applicable safety requirements used initially for its certification without a separate assessment of the modified product."

This is "voiding" of the listing when listed equipment is modified outside of manufacturer and UL approved modifications. An AHJ can still accept the modification without requiring a field certification, but the original UL Listing is still voided by the modification.
 
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