Off-grid inverter dis-allowed by inspector. What is best rebuttal to get approval

[lucariffer]

After choosing a Growatt SPF12000T-MPV inverter (a very nice unit) and having my electrician grid-tie it (3-wire connection to AC IN) to charge a 48V AGM battery bank, the local Ontario inspector (an off-grid solar newbie) in Ontario disallowed the system, stating there is no documentation/user manual reference that proves the inverter cannot back-feed the grid. He was looking for a label, something like "source not grid interactive" and he did not buy the argument that an off-grid inverter is basically an appliance . . he came back saying it was connected to solar and battery power sources. Could someone suggest the best way to offer a rebuttal to the inspector? Do I need to get detailed inverter design drawings from Growatt showing the AC IN is uni-directional? Or should I cave, disconnect the grid-tie charge feature to get a pass, and instead charge the batteries manually with a 120Vac-to-48V charger?

 

[Ampster]

I think your best approach would be to disconnect it from the grid. If I recall the Growatt is not UL listed and I think that listing is the only way to prove that it won't backfeed the grid. Just my 2 cents worth without complete knowledge.

 

[Supervstech]

If it has a grid in for charging, and a dedicated output not tied to your main grid panel it shouldnt be any issue.
If the output connects to your main grid tied panel, then it needs documentation.

 

[Mattb4]

After choosing a Growatt SPF12000T-MPV inverter (a very nice unit) and having my electrician grid-tie it (3-wire connection to AC IN) to charge a 48V AGM battery bank, the local Ontario inspector (an off-grid solar newbie) in Ontario disallowed the system, stating there is no documentation/user manual reference that proves the inverter cannot back-feed the grid. He was looking for a label, something like "source not grid interactive" and he did not buy the argument that an off-grid inverter is basically an appliance . . he came back saying it was connected to solar and battery power sources. Could someone suggest the best way to offer a rebuttal to the inspector? Do I need to get detailed inverter design drawings from Growatt showing the AC IN is uni-directional? Or should I cave, disconnect the grid-tie charge feature to get a pass, and instead charge the batteries manually with a 120Vac-to-48V charger?

One thing you should do is stop referring to wiring it up as being grid-tie. It is simply getting power from the grid (like an appliance) for use similar to a UPS. Grid tie is being in parallel with grid and capable of back feeding.

However if you are going to submit things for inspection in terms of home wiring from the AIO than likely the inspector will want to see certification of components. A emergency power transfer switch arrangement such as for a generator might allow you to get around the inspector as transfers switches would preclude back feed. After which wire in the AIO yourself.

 

[Xhumeka]

How are you planning on using the Growatt? What do you have connected to the AC out of the Growatt?

 

[PreppenWolf]

If you email Growatt will they send an email response confirmation it is not capable of backfeed?

 

[timselectric]

If you said "grid-tied" to the inspector, you should give up. Just by using that term, you have already created an issue. Just disconnect it from the AC input. Get your inspection, if you still can. And you can hook it back up afterwards.
This is all assuming that you have installed it correctly in every other way.
If this was the only issue that your inspector had. I think that you got very lucky.
This is how an incorrect use of a word can really screw things up.