Floating neutral

[LywWyr]

I have 2- 6500ex48 inverters, one has the ground neutral bond screw removed. The other provides the single neut/grn bond location for the system.
I have a 4 pole transfer switch , when using generator power ( 4 wire 240/120vac) , the generator neutral is floating. It's a honda eu6500is inverter model.
Can I just bond the generator neutral and ground conductors at the main panel neutral bar?
Will this damage the generator?

 

[FilterGuy]

I have 2- 6500ex48 inverters, one has the ground neutral bond screw removed. The other provides the single neut/grn bond location for the system.
I have a 4 pole transfer switch , when using generator power ( 4 wire 240/120vac) , the generator neutral is floating. It's a honda eu6500is inverter model.
Can I just bond the generator neutral and ground conductors at the main panel neutral bar?
Will this damage the generator?

In general, the honda generator can have its neutral and ground bonded without damage to the inverter or generator. However, I am not sure what you are proposing and whether it would create more than one N-G bond.

Could you please provide some kind of diagram of your set-up?

Does the transfer switch select between the grid and generator for input to the inverter?

 

[Warpspeed]

I have 2- 6500ex48 inverters, one has the ground neutral bond screw removed. The other provides the single neut/grn bond location for the system.
I have a 4 pole transfer switch , when using generator power ( 4 wire 240/120vac) , the generator neutral is floating. It's a honda eu6500is inverter model.
Can I just bond the generator neutral and ground conductors at the main panel neutral bar?
Will this damage the generator?

The usual preferred method is to ground the neutral right at the power source, or at the main power board when grid connected.

Portable generators are a bit of a problem, because if you ground the neutral at the generator, and there is already a grounded neutral at the main power board, there are a couple of nasty possibilities, if active and neutral are somehow transposed in the generator cable.

Its possible to have both sides of the system grounded, which means a dead short if the earth wire is intact in the generator cable.
If the earth wire in the generator cable is open circuit, then the generator frame may become alive when the generator is started up.

The whole thing needs some very careful thought.
No doubt local codes cover all this, but what applies in one region/country, may be horribly illegal in another region/country.

 

[LywWyr]

My system is off grid and has 2 6500ex48 inverters. Unit one has had the internal g/n bond screw removed. Unit 2 has the n/g bond screw still intact and provides the n/g bond for the system. This is the only location that the n/g bond takes place.
The 4 wire 240 vac power from the inverters feeds a 4 pole transfer switch . It then goes to a 200 amp panel with isolated grounds and neutrals.
My question is , How do I hook a honda Gen with a floating neutral to the system.
I want to tie it into my transfer switch , so I may easily switch to Gen power on cloudy days.
I attached a diagram, I will agree it is a sorry drawing at best.
Do I simply bond the neutral and ground from the Gen at the transfer switch to create a n/g bond while in generator mode?
I understand the n/g bonding as I am an electrician, but I have no experience with generators that have floating neutrals.
My drawing does not show it but all the boxes , panels metal parts etc.. are properly grounded.
Thank you

 

[FilterGuy]

Thanks for the drawing.

1) It looks like the ground is being switched. Do not switch the ground. They should all be tied together.

2) The Honda generator will not be able to power anything near what the inverters can. (The generator is rated for ~6500W and the inverters can do 6500W each)

3) It looks like the neutral from the generator is not connected at all. Is that an oversite in the drawing or are you just waiting to find out how to hook it up?

For the setup you show, One solution would be to connect the generator neutral to the neutral on the transfer switch and permanently bond it to ground.



An alternate way of doing it would be to remove the bonding screw from *both* inverters and put a bonding jumper in the distribution box.



In this arrangement, switching neutral is no longer necessary so It can be simplified to this:




4) The inverters have built-in transfer switches. Is there a reason you are not putting the Generator power through the inverters? You could set it up like this:

 

[LywWyr]

Thank you for you response.
1) If you are referring to the ground at the transfer switch as the ground being switched, that is an error on my part. The ground does not pass through the transfer switch. Sorry.
2) I know my Gen is undersized , but my house is only 2 occupants, 1000sq ft and pulls less than 20 amps @240 with both ac units and the fridge running. If we are in Gen mode we just monitor our usage .
3) I was waiting.
4 ) I was hesitant to run the undersized Gen through the inverters. Thought it would be best to feed the house directly and use a small stand alone charger plus let the pv get what it could into the batts..
The first diagram you show is what I was attempting to describe. Bonding the Gen grn and neutral.
That's how I will wire it.
Thank you.