Hi guys, For some commercial customers installing a bus tap instead of potentially removing some sections and installing new sections would be a cost saver. However, the bus that is at the main that is being touched/drilled/re-lugged might not be NEC/UL compliant after the pull section integrity has been "compromised". Any feelings on this? It's starting to come up a lot and we're discussing if this might be against the AHJ.
Agreed. Whenever I have had the existing bus drilled out to land additional cables I have had to arrange (and pay) for the UL folks to make a trip to the field to revalidate the UL listing because the equipment had been changed from the way that it was originally tested. I wasn't crazy about the added expense, but the insurance wouldn't have paid in the event of an incident because the equipment would have lost its UL listing otherwise.
From what I've been reading, ghost307, it looks as though this is the only option. UL or NRTL is going to have to for a field visit to inspect and re-certify the bussing. I assume this is pretty expensive...
Just a few years ago, this very forum had nice chats where we discussed the drilling & tapping of bussbars- among other things. I dare say that ours is a construction trade, where we fabricate things on a daily basis. The stuff we get at the parts house is only our raw materials - none would expect it to be the 'finished' product!
I know several folks here have cut, drilled, tapped, bent, cleaned, and otherwise altered bussbars. Many have also had parts fabricated to replace discontinued products.
I don't know the exact circumstances of the OP's situation, so I cannot offer a specific opinion as to where the proposed work is wise. By the time you get your masters' or contractors' license, you're supposed to have some idea as to your own limitations.
"Equipment not evaluated ...."
This is the biggest bit of folderol of all. NOTHING is evaluated as we use it. Period.
For example, I did a lightning system today. Neither the UL-listed wire nor the UL-listed ground rod were ever evaluated by UL for use with the UL-listed Cadweld system. Yet, Cadweld is used successfully millions of times each week.
(I'd say 'look it up,' but UL asserts ownership of their standards, and want you to buy them. Well, we can't have just anyone reading them now, can we? You'll just have to trust me on this one).
We've also seen the silly assertion by UL that male NPT threads are suitable for use with only "certain" NPT female threads. Go figure!
I have had numerous situations where modifications, or repairs had to be performed on buss, both in switchgear, and distribution buss.
The ECs called in a fabricator who operates a UL approved shop to fabricate and/or install what had to be done. Yes, when it was completed a UL document was presented and a 'field label' was put on the equipment.
This one shop also makes custom switchgear, buss tap boxes, and POCO approved CT cabinets.
Yes, the cost is premium, but the results are 100% no issue. Overall it usually is cheaper then a "do-over".
Think about the litigious society we are all living in, and everyone having to 'watch their backs'; doing our jobs 'by the book' is the way to go.
Ok guys, a lot of good feedback. The main concern here is having a customer that can't afford to spend another $25k on a new piece of equipment and having a POCO/AHJ being a little more flexible about being "by the book".
Thanks again, I'm prolly going to have to call UL and find some local guy.