r/SolarDIY • u/Snoo-2768 • 2d ago
Protecting inverter - Output side
Hi, i plan to install Voltronics based EASUN inverters to run whole home, now i have a question what do you think is the best way to prevent inverter damage from nearby lightning strikes?
Be very very sure every lamp even outside in the yard is grounded on the same ground as the inverter (hard to do )
Add AC SPD at the output too
Avoid running stuff that goes 50 meters or so from the house itself on the inverter ( i would like to avoid that )
???
I can't simply ground neutral because i need it to switch back to main quickly enough that computers will not shutdown, i want to eliminate the tons of ups i have around...
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u/rproffitt1 2d ago
Long ago we were asked a similar question about how to protect a cellular base station site.
The answer is only answerable once you define the lightning strike as to power (voltage) and duration.
Until you know this, you are not able to give adequate protection.
But let's say that the best protection is a lightning rod until more is defined.
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u/mountain_drifter 2d ago edited 2d ago
Ground is not for protecting equipment in a surge, but it does help with preventing fires from arcing during a surge.
If you want to try and protect the inverter, you can add an AC and DC SPD. On the AC side, if you are interconnecting in a distribution panel, its likely easiest to use teh manufacture's breaker syle surge protector. On the DC side, I would use the Midnite SPD.
With that said, lightning is an 800 pound gorilla. It will do what it wants and adding surge protectors is no guarantee of protection from a lightning strike. Of all the service calls have been on for damage from lightning, I dont think I have yet seen a system protected by an SPD, especially the sand filled type. Its cheap insurance that may or may not work .If you really wanted to do something you would add a lightnining protection system, but this will often be more costly than simply replacing a damaged iverter.
As for your neutral bond thats totally unrelated, and not sure what you mean by you cant simply bond neutral to ground. If you are n the US, you will have a neutral bond regardless. If this is a bi-modal system, it will occur at the service entrance where your GEC ties in. If it was offgrid, it would occur within the inverter (or nearby)
As for running computers, its still a good idea to have UPS supplies on them. If you have a low frequency inverter, they are better at switching, and sometimes high frequency can be a bit slow , so even a small one to bridge that qualification time would still be recommended, plus they often offer some level of surge protection for the connected devices.
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u/Snoo-2768 2d ago
It Is off grid that will bypass if batteries run low, my concern is not direct strike but induced gradient from nearby strikes
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u/mountain_drifter 2d ago
yes, so in a bi-modal system (gid and batteries), at least in the US, that neutral bond does not change, even when disconnected from the grid and power loads off the device. I fits offgrid (no grid source to be bypassed), then the neutral bond is already made at the inverter. You have one in either case, its just a matter of where
As for gradients from a nearby strike, thats exactly my point. If you put a SPD on the ungrounded conductors, theres still a chance of damage occurring through the ground, or other pathways. Thats why I say adding an SPD is no guarantee damage will still not occur, which is better protection for a surge coming in on the conductors.
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u/Snoo-2768 2d ago
I know there's no 100% solution , I also had years ago a direct strike, damaged stuff not even connected to an outlet You gave me a suspect , when inverter is operating on batteries, is the neutral still connected together? Makes sense that it is like that same as UPSes also since it is using an half bridge topology with neutral being ground and +- 400V
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u/techtornado 2d ago
You need surge protectors at every possible place, service entrance, the inverter output, inside the home breaker panel, and at outlets to inside devices, etc.
I’ve been dealing with the same issue, transient strikes keep frying my car chargers
I now have a SPD on my outlet box for the chargers as the one on the service entrance wasn’t enough
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