I'm not really seeing it. UL is for the entire package. I don't see how you can possibly UL a replacement board successfully. For the finished unit to be 'UL' it would have to have been assembled on a UL certified assembly line. Showing up with an aftermarket 'piece' that an end-user installs invalidates the listing since it won't have been assembled on a certified line.

I'd also expect a certification to cost about $20k~30k.

You'd also go to all the bother only to have some ebayer under sell you by a lot since they aren't going to UL anything.

I'd suggest building a solid, safe, protected, drop in replacement and selling it on - Ebay and Amazon type places yourself. If people want to repair their inverters they can buy your replacement and be back in service. Don't discuss the UL ness of it. If they're dead set on having UL they should cycle out their ancient inverter and put in a new UL one.

Keith Cress
kcress - http://www.flaminsystems.com

Thanks Keith, I agree. I have not found any organization willing to recertify new components within an obsolete chassis, and obviously you can't test the board by itself - it needs all the associated control boards, I/O boards, and cooling systems to do anything at all! It'd be great if there was a way, similar to what the automotive industry has for aftermarket parts. Alas, if it's there, I haven't found it. Thanks again.

Yep. But if you think it's a valid market then go for it as there will probably e people willing and grateful to pay who don't care about a listing. Just run your board by a third party to root out any hazards.

As you probably know you can't UL list a component, instead it's the backwards UL mark meaning that the component is ostensibly UL listable in a finished product. That means it's assembled with backwards marked UL parts and ready for testing. If you want a UL mark and want to spend for it you could probably get that mark.

Keith Cress
kcress - http://www.flaminsystems.com