Has anybody posted pic of the screws internally bonding the neutral to ground inside these SPF5000ES models? 9 pages of thread comments and found nothing, LOL. I really need it presently. I found one screw, poking around before I disassemble, but before I go tearing into these to delete them and insulate the PCB, it'd be nice to know where others have removed them in case there are multiple. Regarding insulating the PCB, wow people get all technical. Just put a good insulator between standoff and pcb and be done.
Despite getting all my AC wiring install and new panels installed correctly without cross-shorting L1 and L2 on any of my (4) new units, I simply didn't think to check for that internal neutral-ground bond. It happens. It's not mentioned anywhere. It didn't dawn on me, mostly because there's no reason this should have been done internally, in the first place by the manufacturer, it should be an external removeable jumper wire to make it US or EU compatible. My fault for not thinking of it, but I ended up with blown up inverters as a result, when parallelled. Why Growatt had no idea what I was experiencing, is beyond me. I was in communication with (3) separate Growatt engineers over this past month, one in UAE, one named Francis in California, and another in China. Then again, the same engineer in California told me my warranty was invalid because the unit's display showed 175% load (overload) after the failure despite it being obvious there was no load connected at all. He said I was overloading it. Mind you, the unit as designed wouldn't even run for a second at that loading, and he somehow didn't know this.
Some thoughts, since I've been through the mill already on this:
Opening your unit won't void the warranty. Why? Growatt engineers ( at least in UAE, China and California) insist the customer open the units themselves, they have no intention apparently to ever replace the whole unit under warranty. Because they're too cheap to replace the whole faulty unit. At least not to my experience. They insisted I open the unit and diagnose which boards were faulty. Then simply told me they've never seen this problem before, it's unusual, and all my fault. Not sure how a non-technical person would have even handled doing this.
I've obtained one for one replacement units for those blown up here due to the situation. With no help from Growatt, mind you. Their engineers had no idea of this thread's ground-neutral situation, and simply blamed me for blowing them up. No warranty-case closed. So be warned, Growatt support is no better than any of the China fly-by-night clone manufacturers, so save your money, these things are basically disposable. They looked for any reasons to deny warranty, then insisted on knowing the serial numbers, I'm imagining to maintain record of the rejected units' warranty in their system. Unless local selling guys like Signature Solar want to replace them out of the goodness of their hearts. China manufacturers are not like those in the US, or Europe or Japan for that matter, they're generally heartless and fraudulent. Back when I put myself through university repairing electronics, we could most always get wiring diagrams/repair manuals/schematics from the Japanese and German manufacturers. In my best Changlish: "China no help". "You steal technorogy".
Those remarking we're mistaken buying these for the US are incorrect. Yes, there are US models with transformers already inside, but when I priced these, I needed (4) and with shipping all that weight and the price difference, it was literally thousands of dollars saved. And I already own a couple good autotransformers. There was a newer US model that looked perfect, but it was unavailable at the time. If not for this silly internal neutral bond issue, all would be well and this thread wouldn't exist in the first place. These work fine with 50Hz or 60Hz, 230V or 240V. No reason not to use them, except maybe for UL-listing, which most China factories fake anyway, it's useless. Just buy from a reputable manufacturer, should be fine without a UL sticker.
Regarding grounding, yes, don't drive another ground rod just for these inverters, separate from the main building ground. Or at least if you do, interconnect them. As I stated before, you'll get current between them possibly causing RF interference, and added lighting risk, because there will always be some tiny ground potential between them. Remember, per NEC we're supposed to have 2 driven ground rods a minimum 6 feet apart (code changed to require this a few years back) , so you could kill 2 birds with one stone here adding the second. But interconnect them with a #6 copper conductor. Or just use one rod(other NEC option) , and get a testing device to ensure below 25 ohms to ground, I believe it is. Most don't bother with the latter.
I hope this info helps others. I'm not interested in arguments over this stuff. If I'm incorrect in any of the above, you're welcome to correct me. If somebody could post the pics of the PCB for others to handle themselves, it would be most appreciated.
Edited: Found the pics, thanks. I removed the screws, looks to be ok, there's no copper or via exposed at the bottom. The first inverter, I disassembled, and removed the standoff, it comes off easily with a vice grip, bend a few times, it then falls out the bottom. Doesn't look necessary now though, at least for the models I received. There is no copper at the bottom of the hole or via present.
One more note. I keep seeing smartass comments about these being inappropriate for our use, and we should be using the split phase version. But the neutral issue that most of these threads discuss, is just the same regardless. Connecting the split phase inverter's supplied neutral to ground without eliminating it at the service, versus our supplied separate autotransformer, it's the same issue. The only difference I see, is some installations will have a neutral relay and some will have temp protection for the transformer. The first isn't needed if you design your setup correctly, nor in my opinion is the second, if you trial test your installation for a week or two, see how much imbalance you can possible have at any one time, and move a load or two to the other phase. Just my thoughts.
Bill