Most inverters ok if not for selling power into grid

from what i glean here my old axpert is 100% legit - even if not on ct list - as long as i do not push power into grid!
Best entry-level inverter that's NRS 097-2-1 approved - Inverters - Power Forum - Renewable Energy Discussion :grinning:

The way I understand it - if it connects to solar panels and to the grid in any form, it has to be NRS approved. Your old axpert is perfectly fine as long as you either don’t have any connection to it from the grid, or don’t have solar panels connected to it.


:slight_smile: @_a_a_a … separate dbs are also essential, feed in from both grid and solar but only possible feed out to load
there are no supreme court test cases on this, so common sense, good faith, best practices and compliance to electrical standards are called for - not political and marketing pressure - common sense and bona fides!

I think we discussed this to death about 5 or 6 years ago, on another forum. They want to see that someone tested and made absolutely sure that the PV will never find a path to the grid. Even if the hardware is designed in a way that makes it completely impossible, unless it was TESTED, you’re going to end up in that gray area… that area where you fill in the “off-grid” part of the form, and hope they never ask if you have the AC-input connected to the grid (which of course, you do).

If you want to be sure, don’t buy an Axpert. If you already have an Axpert… well, might as well take your chances then I suppose :slight_smile:

indeed @plonkster … a grey area in which your conscience is referee until tested in court, so i rest assured my axpert is ok!

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And this was an interesting video: All-in-One Solar System: 2 Basic Rules for Shock Hazard Prevention - YouTube

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If I have to guess, that’s the models with the high voltage PV inputs. The PV is switched (buck/boosted) directly onto the High voltage DC rail, which is often directly connected to the AC input via only a rectifier (though, typically a little smarter than just 4 diodes).

It’s not an unusual arrangement, many of your “transformerless” PV-inverters work like that.

The Axpert @gabriel has, if I recall, is one of the old types with the 150V PV input, MPPT going to battery, and then an inverter in the same box. For those, at least, the worst you will see on an open PV connector is battery voltage.

For those old double-conversion Axperts, it came down to the same old discussion about a “suitably interlocking” changeover switch, which switches both live and neutral, and which you must have if it is a “standby sseg (Passive standby UPS utilised as an standby hybrid SSEG)” system, which to my knowledge at least the early Axpert’s didn’t have. They had individual relays, and the neutral of the inverter wasn’t switched.

(Nothing wrong with individual relays if a relay test is done before connecting, just to be clear :wink: ).