Growatt 3kw wiring question

[FilterGuy]

Just FYI, arc fault protection is now required by code at most rooms in a house, unless your jurisdiction still has not adopted this reqt. Existing homes are exempt until any change is made to the system, then the reqt kicks in.

https://www.nfpa.org/assets/files/AboutTheCodes/70/Errata_NEC%20Handbook_2020_Article_210.12(A).pdf

Interesting. I had not picked up on that. Is that new to the 2020 rev of the code?

 

[Sojourner]

Interesting. I had not picked up on that. Is that new to the 2020 rev of the code?

From what I understand, the 2011 code hinted at this new reqt. Then it became required by the 2014 code. Then it was further modified by the 2020 code to be more restrictive. So it depends which version of the code the local jurisdiction has officially adopted, but most likely they have at least adopted 2014 version by now.

I need to look into how much (more) this new type of receptacle and breaker cost vs standard or GFCI only. I'm betting it's significantly more of course.

 

[FilterGuy]

I need to look into how much (more) this new type of receptacle and breaker cost vs standard or GFCI only. I'm betting it's significantly more of course.

A quick search of amazon says $25-$30.
https://www.amazon.com/Leviton-AGTR2-W-SmartlockPro-Function-Receptacle/dp/B01CG8MTN4/ My guess is that if you buy wholesale they are somewhat lower cost.

The interesting thing is that the AFCI/GFCI combos are about the same price as just AFCI.

As a comparison, a GFCI outlet is in the $10 range.

 

[FilterGuy]

Another interesting thing about the the AFCI requirement is that they are not requiring the AFCI be at the breaker box.... it is ok if it is at the first outlet. This tells me that they are worried about what gets plugged in having arc faults.... not the house wiring.

 

[John Frum]

Another interesting thing about the the AFCI requirement is that they are not requiring the AFCI be at the breaker box.... it is ok if it is at the first outlet. This tells me that they are worried about what gets plugged in having arc faults.... not the house wiring.

I don't have any AFCI protected circuits, is there something technologically similar to test extension cords?

 

[FilterGuy]

I don't have any AFCI protected circuits, is there something technologically similar to test extension cords?

I am not aware of any.... but I have never looked for anything either. I guess you could build one with an AFCI socket.

One thing to note is that the nature of arc faults means they are often (Mostly?) an intermittent type of event due to a loose connection. Initially it is making contact and carrying current and then the connection breaks forming an arc that is then sustained due to the ionized air formed by the arc. It is unusual (but not impossible) for an arc to form on a broken connection. That means an extension cord could 'test' good unless you happen to pull or bend it in just the right way during the test.

Also note that the AFCI has to distinguish between a sustained 'bad' arc and 'normal' short duration arc due to turning off a switch or unplugging a device.

 

[Sojourner]

Another interesting thing about the the AFCI requirement is that they are not requiring the AFCI be at the breaker box.... it is ok if it is at the first outlet. This tells me that they are worried about what gets plugged in having arc faults.... not the house wiring.

Right, apparently X amount of people die each year from arc faults at outlets/devices/appliances that GFCI protection doesn't cover. So now it will be AFCI almost everywhere an outlet may be commonly used. The dedicated outlet at a refrigerator, for example, doesn't require this protection because it's rarely accessed.

 

[John Frum]

Right, apparently X amount of people die each year from arc faults at outlets/devices/appliances that GFCI protection doesn't cover.

GFCI protects people from shocks.
From memory AFCI protects people from fire.
AFCI was first mandated for bedrooms where arcs in cords could ignite combustibles like bedding etc.

 

[Sojourner]

Another interesting thing about the the AFCI requirement is that they are not requiring the AFCI be at the breaker box.... it is ok if it is at the first outlet. This tells me that they are worried about what gets plugged in having arc faults.... not the house wiring.

speaking of "the first outlet"...
When locating first outlet in a circuit (to change to fault-protected type, etc), I thought this video shows an interesting method (starting at about 5min in)...

But then, rather than buying such an expensive device as that Ideal circuit analyzer, I thought the same could be done with a voltmeter and a hairdryer, spaceheater, or heatgun as the applied load to determine voltage drop.

 

[Sojourner]

GFCI protects people from shocks.
From memory AFCI protects people from fire.
AFCI was first mandated for bedrooms where arcs in cords could ignite combustibles like bedding etc.

I guess all those poor people they refer to were dying in fires.

 

[JAS]

Just curious... I was hoping to do the exact same setup (I believe)...

I already have a ProTran that I plug my generator (floating N) into. Was hoping to plug the GroWatt into this as well. The part that has my brain a bit fuzzy is this:

From my main panel, I will feed AC in to the GroWatt (for purposes of battery charging and "Grid Assist" or "AC Failover", or whatever Growatt calls it). The GroWatt in turn, feeds the ProTran, which, as stated, is connected into the same main panel that is feeding the GroWatt AC input. Sort of a loop of AC current leaving the main panel and coming back in, via the GenTran. As long as the circuit feeding the GroWatt can handle the load, I don't see a problem there. But, the N/G bond has me wondering... Assuming the GroWatt is just passing AC power through, wouldn't that create the double N/G problem?

 

[JAS]

Well.. the more I think about this, I'm pretty sure the N/G bond is being passed through the GroWatt (from the main panel) back into the ProTran (which does NOT switch Neutral). Therefore, there are two N/G bonds. Removing the GFCI is a workaround, but I'd still be concerned that there are two N/G bonds in the circuit.

In my case, I think the safest bet is to replace the ProTran with a typical sub-panel with an interlock switch (so I can switch back to the Mains in case of an issue with the Growatt)

 

[2018Keystonepassport]

I have a 3000W Renogy Inverter trying to run RV AC for short periods with 400Ah Ampere time batteries with trailer 30amp plug and OEM converter charger breaker off but Inverter shuts down on GFCI. Only happening when AC tries to run but can’t do other loads fine (fan, fridge, TV). Any ideas? Interestingly, it was working last week and I haven’t changed anything that I know of.

 

[derekisastro]

These drawings you provided represent before and after my reconfiguration.

I did not test for current on the ground and will recheck this weekend.

Were you able to confirm or deny the neutral ground bond status in the Growatt?

Edit for spelling ...

 

[rjpear]

I have installed a 6 circuit Reliance Controls generator sub panel transfer switch 30 amp 120v. It has 6 circuit breakers in it that I have wired to 6 circuits in my main panel. Three of the circuits in my main panel that I connected are GFI breakers. The generator panel is fed with the Growatt 3kw inverter. When I switch the 3 circuits on the sub panel to be fed from the inverter, that trips the GFI circuits in the main panel. The circuits on the sub panel are running fine. I am not sure why this is happening and if it is an issue (I assume it is)? I have successfully wired these panels in other houses, but never to GFI breaker circuits in the main panel.

BTW, I did the generator subpanel so I could also switch and feed it directly with a generator if I had to.

Any help is appreciated!

Jim, Thanks a bunch for the picture of your setup. I just got a Growatt 3k and a 48Volt Battery Kit (to be used as a Backup for GridDown) and was wondering on how to best get the thing setup. I have an older Generator Transfer Switch as was just going to toss that and go the SubPanel route but after seeing how you wired yours up to the transfer switch I may go that route. Question though.. The Outlet that is powering the Growatt... is that on a special breaker (40 amp) or just standard household? Thanks for all the research and work you are doing...and the Forurm/Group members for helping out!..

 

[derekisastro]

Jim, Thanks a bunch for the picture of your setup. I just got a Growatt 3k and a 48Volt Battery Kit (to be used as a Backup for GridDown) and was wondering on how to best get the thing setup. I have an older Generator Transfer Switch as was just going to toss that and go the SubPanel route but after seeing how you wired yours up to the transfer switch I may go that route. Question though.. The Outlet that is powering the Growatt... is that on a special breaker (40 amp) or just standard household? Thanks for all the research and work you are doing...and the Forurm/Group members for helping out!..

You definitely want it on its own dedicated circuit/breaker ... if you're hoping to ever get close to the 3000W from the inverter, there could conceivably be a time when, if your pulling the 3000W and need to do this from the grid, you'll be pulling 25+ amps ... no standard home circuit will support that for long.

 

[JAS]

You definitely want it on its own dedicated circuit/breaker ... if you're hoping to ever get close to the 3000W from the inverter, there could conceivably be a time when, if your pulling the 3000W and need to do this from the grid, you'll be pulling 25+ amps ... no standard home circuit will support that for long.

I'm glad this came up... I see this GroWatt has a surge of up to 6000W. That's like a 50-60A circuit ? I'm planning on setting up in my detached garage and feeding my transfer switch in the house (about 80' away). So that's like a 6 gauge cable. Holey expensive batman! I already have a 10 gauge cable running out to the garage feeding 30A 240v subpanel. I was thinking I would just pull a 20A circuit out of that sub panel to feed the AC input of the Growatt. I don't plan on pulling any more than 15 amp load from the Growatt. But, if it ever happens, I assume the 20A breaker feeding the AC in of the Growatt will just trip... Any big problem with this?

 

[FilterGuy]

I'm glad this came up... I see this GroWatt has a surge of up to 6000W. That's like a 50-60A circuit ? I'm planning on setting up in my detached garage and feeding my transfer switch in the house (about 80' away). So that's like a 6 gauge cable. Holey expensive batman! I already have a 10 gauge cable running out to the garage feeding 30A 240v subpanel. I was thinking I would just pull a 20A circuit out of that sub panel to feed the AC input of the Growatt. I don't plan on pulling any more than 15 amp load from the Growatt. But, if it ever happens, I assume the 20A breaker feeding the AC in of the Growatt will just trip... Any big problem with this?

You don't typically size the wire for surge currents. Surges are, almost by definition, very short in durration and do not have time to heat the wires. As an example, I just checked my Air conditioner and it surges to 116 amps at start up but it is wired with 10AWG.....

 

[FilterGuy]

You definitely want it on its own dedicated circuit/breaker ... if you're hoping to ever get close to the 3000W from the inverter, there could conceivably be a time when, if your pulling the 3000W and need to do this from the grid, you'll be pulling 25+ amps ... no standard home circuit will support that for long.

A dedicated 30A circuit with a 30A plug is what is needed. I personally like the NEMA L5-30 twist-lock 30Amp 120V plug and receptacle for this requirement.

 

[derekisastro]

A dedicated 30A circuit with a 30A plug is what is needed. I personally like the NEMA L5-30 twist-lock 30Amp 120V plug and receptacle for this requirement.

Or simply wired directly to the 30amp breaker in the panel ... no outlet and/or plug needed.