Again Generator Neutral bonding advise needed

JBoyKey · February 2021

New to the forum, thanks for the add. Searched and read all Threads on this topic, but still confused, have the following:
Growatt SPF-6000T-DVM 6k 240v low frequency split phase Inverter Charge Controller
Westinghouse WGen7500DF Generator - Neutral bonded to FRAME
Growatt says L1, L2, and Ground from Gen to Inverter input breaker panel - no answer about Gen being Neutral bonded to Frame.
Ground if from my house panel with bonding to neutral there, ground to all panels in the Solar diagram is seperate, and
will have lockout dictate Grid or Gen input on breakers, all manual transfer, and restrict Utility charge amps Should I remove the Neutral
bonded to frame on Gen?
PLEASE review attached picture highlights and any advice is appreciated, Joe.

Image: https://us.v-cdn.net/6024911/uploads/editor/na/osf8v8bi409j.jpg

BB. · February 2021

You would lift the Neutral/Ground bond here (in red--From what I can see). Looking at the genset itself--I suggest that if the genset is designed for lifting the ground bond, it should be easy and obvious):

Image: https://us.v-cdn.net/6024911/uploads/editor/z3/hyu2pw2wn83i.gif

And connect your home system to the L14-30 outlet (120/240 split phase 60 Hz + Genset Frame Ground, now with "floating" neutral/AC L1+L2 connection).

Of course, if you run the genset as a stand-alone unit, you should reconnect the G/Y neutral/frame ground...

As always, this is just a quick review of your genset--These are decisions/actions that are your responsibility

I guess you could make a dongle for the L14-30 (jumper the Neutral+Ground in the plug or adapter).

Also, I think you need the Neutral+Ground to your main panel and Ground+Neutral bonding in the main panel (should already be there in typical home).

-Bill

JBoyKey · February 2021

Got it, no place to hook neutral at Growatt - only requires L1, L2 and ground from Main house panel, which does have bonded neutral to ground and ground rod, Growatt has a 85lbs transformer that takes 240v and creates it's own neutral, That's what I got from other post, stand alone is bonded neutral to frame and 240v 30a plug - no bonding, Joe. Thank you,

BB. · February 2021

Interesting... Then your "protected" 120/240 subpanel from the inverter will have a neutral+ground bond?

If your genset is only connected to the GrowWatt AC genset 240 VAC input--Then you really do not need (or want?) to lift the neutral/ground bond inside the genset. L1+L2 still should be "ground referenced" via the internal neutral+ground connection (if L1 or L2 is shorted to ground, you want to trip the genset breakers).

There is no "neutral current" between the genset and load (AC inverter genset input). So no neutral+ground parallel current flow from loads).

-Bill

JBoyKey · February 2021

Thanks, will keep you posted when Growatt answers back, gen will arrive tomorrow, plug, wire ans 30a extension cord on Wednesday, Joe.

mike760 · February 2021

Your main panel should be bonded. I think the easy way to think about it is that if your transfer switch does not change the neutral to ground connection when it flips, then you want your generator to operate in a floating neutral mode (not bonded). The frame of the generator should still be connected to a grounding rod.

JBoyKey · March 2021

Update - It works perfect, bit the bullet and replaced new #6 - 3 conductor from house panel with another new #6 - 4 conductor, REMOVED NEUTRAL TO GROUND BONDING on Gen and wired it exactly like Watts247 schematic said to but without transfer switch. Using Back fed breakers so single point neutral to ground is at House panel and never gets removed, see updated pic, yes @Mike760 will be grounding Gen to separate Rod, thanks for Everyone's help, Joe.

Image: https://us.v-cdn.net/6024911/uploads/editor/ma/2p6f56ekz0wh.jpg

BB. · March 2021

You only "need" a ground rod at the generator (frame ground) if you have significant chances of a lightning strike in your area.

You already have Green wire from House Grounding, so your 'AC' safety grounding is taken care of.

If your genset is a "belt and suspenders" backup, and you have significant chances of lightning--"Unplugging" and rolling up the cord (air gap between genset and home) for the genset when stored/lightning is present (or predicted)--You can save a strike taking your 2nd level backup power down too (along with utility/inverter too).

And if lightning is a possibility--You should also put putting surge suppressors "everywhere" (on solar panel line to home, AC main panel, genset input, etc.):

https://www.solar-electric.com/search/?q=midnite+surge (pick one, installation manual and guides on product page)

The above are very nice... The are MOV (metal oxide varistor) vs the "simple spark gap+sand" in many other suppressors:

https://www.solar-electric.com/search/?q=midnite+surge

-Bill

JBoyKey · March 2021

Thanks @BB. Gen is 7500w portable on rubber feet, have a separate ground rod not from Solar Panels to ground Gen chassis with. Have always had Lightning and surge protection/combiner.

Again Generator Neutral bonding advise needed

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