Bonding With A Breaker?

[LSC]

I know there has been a lot of discussion on this and some by me. I have a small system to use as a brownout type situation and the whole thing can be moved around. With all that I use a plug to connect to the AC outlet. If that plug is removed from the outlet then I will lose my bond for N and G.

So I wondered if a breaker could be used to connect N and G if the plug is removed. The breaker is a 1P and is AC rated at 110Vac and 40A. I included a picture to show the breaker and part of my circuit. Also, I am still uncertain as to whether this breaker, if used, goes in the AC OUT breaker box or the AC IN? Any help appreciated. Thanks

 

[FilterGuy]

I know there has been a lot of discussion on this and some by me. I have a small system to use as a brownout type situation and the whole thing can be moved around. With all that I use a plug to connect to the AC outlet. If that plug is removed from the outlet then I will lose my bond for N and G.

So I wondered if a breaker could be used to connect N and G if the plug is removed. The breaker is a 1P and is AC rated at 110Vac and 40A. I included a picture to show the breaker and part of my circuit. Also, I am still uncertain as to whether this breaker, if used, goes in the AC OUT breaker box or the AC IN? Any help appreciated. Thanks

I could not find a manual for a Chins 3K inverter so it is a bit difficult to answer your question. (A lot of these have manuals that are so bad it might be difficult anyway)

First, you need to determine if the Chins inverter does dynamic bonding. If it does, you don't need to do anything because the inverter takes care of it. (My guess is that it does dynamic bonding.....but that is just a guess)

If it does not do dynamic bonding then it probably does no bonding and hopefully allows a common neutral throughout the system... otherwise I am not sure how it could be safely wired.

Assuming it does not do dynamic bonding and allows a common neutral then it needs to be wired like this:


With this, you do need to be worried about creating an N-G bond when not plugged in. A 40A breaker is an interesting approach. If there is a ground fault, the 25A breaker will pop first (that is very good.... you don't want to lose the bond in a ground fault).

Of course, the big downside is if you forget to flip the breaker on when unplugged or off when plugged in.

There is a similar situation with the older versions of the Growatt (The old version did not do dynamic bonding). The best solution I could come up with was to use a relay that is powered by the grid AC:



The relay would be in place of your bonding breaker and would automatically do the appropriate bonding when the system is plugged in or unplugged.

 

[LSC]

I could not find a manual for a Chins 3K inverter so it is a bit difficult to answer your question. (A lot of these have manuals that are so bad it might be difficult anyway)

First, you need to determine if the Chins inverter does dynamic bonding. If it does, you don't need to do anything because the inverter takes care of it. (My guess is that it does dynamic bonding.....but that is just a guess)

If it does not do dynamic bonding then it probably does no bonding and hopefully allows a common neutral throughout the system... otherwise I am not sure how it could be safely wired.

Assuming it does not do dynamic bonding and allows a common neutral then it needs to be wired like this:
View attachment 97698

With this, you do need to be worried about creating an N-G bond when not plugged in. A 40A breaker is an interesting approach. If there is a ground fault, the 25A breaker will pop first (that is very good.... you don't want to lose the bond in a ground fault).

Of course, the big downside is if you forget to flip the breaker on when unplugged or off when plugged in.

There is a similar situation with the older versions of the Growatt (The old version did not do dynamic bonding). The best solution I could come up with was to use a relay that is powered by the grid AC:

View attachment 97701

The relay would be in place of your bonding breaker and would automatically do the appropriate bonding when the system is plugged in or unplugged.

I did contact them a while back and they said that there is NO bond between N and G internally but the two Neutrals of AC In and AC Out ARE tied together internally. With that info does that change anything?

You showed a connection between the neutrals of the AC In and AC Out. Is that still the same, as well as the relay? Thanks

 

[FilterGuy]

I did contact them a while back and they said that there is NO bond between N and G internally but the two Neutrals of AC In and AC Out ARE tied together internally. With that info does that change anything?

It clarifies the situation.

Since the neutrals are tied together internally, you do not need to add the wire I showed above. Your original drawing is fine.

For bonding, something like the breaker would work but you must remember to switch it each time.

An alternative is to add a relay like this:


Just search amazon for 120V 30A relays and you will get several options.

 

[LSC]

It clarifies the situation.

Since the neutrals are tied together internally, you do not need to add the wire I showed above. Your original drawing is fine.

For bonding, something like the breaker would work but you must remember to switch it each time.

An alternative is to add a relay like this:
View attachment 97725

Just search amazon for 120V 30A relays and you will get several options.

Thank you so much, I have been struggling with this for a while and wondering how to do this the correct way to avoid any problems. I will look into your suggestion and add this to my system. Thanks for your help.

 

[LSC]

For bonding, something like the breaker would work but you must remember to switch it each time.

I was wondering if I could just leave the breaker On all the time. Or would that cause a ground loop. The way it is wired shows it is in parallel with the AC cord. N of the breaker is in parallel with the cord N as well as the G of the breaker is in parallel with AC cord G. The only difference is the G and N are tied through the breaker.

Also another reason I am wondering about using the breaker instead of a relay is that the relay would have to be energized all the time in the NO position while the cord is plugged in. I wonder if that could introduce a hazard.

 

[FilterGuy]

I was wondering if I could just leave the breaker On all the time. Or would that cause a ground loop. The way it is wired shows it is in parallel with the AC cord. N of the breaker is in parallel with the cord N as well as the G of the breaker is in parallel with AC cord G. The only difference is the G and N are tied through the breaker.

Looking closer at the circuit, I see what you mean, but it is a problem. (I am not sure why I did not spot it before)

* When you are plugged in, the bonding breaker needs to be off or there will be two N-G bonds on the house's circuit even if the 25A breaker is off.
* However if the 25A breaker is off, the bonding breaker will not generate an N-G bond for the inverter side of the system. The breaker needs to be connected between Neutral and ground on the inverter side of the 25A breaker. (The same is true if you use the relay)

Also another reason I am wondering about using the breaker instead of a relay is that the relay would have to be energized all the time in the NO position while the cord is plugged in. I wonder if that could introduce a hazard.

The relay will be OK as long as it is a continuous-duty relay.

 

[LSC]

The breaker needs to be connected between Neutral and ground on the inverter side of the 25A breaker.

Okay, I have moved the N connection for the bond breaker from the cord side to the inverter side. Is this what you are saying based on the picture?

 

[FilterGuy]

Okay, I have moved the N connection for the bond breaker from the cord side to the inverter side. Is this what you are saying based on the picture?

Yes. That is the way it needs to be wired.

 

[LSC]

Yes. That is the way it needs to be wired.

Great! Thank you so much for the help! Now I just need to set the parameters on the CHIN for LIFePO4 batteries. It looks as if they are set for GEL. I think I saw a video once where Will showed what values to use. Need to find it.

 

[LSC]

Well I couldn't find the specific video I was looking for just the one for Battle Born. So if anyone knows what these values should be set at for LIFePO4 batteries at 24V (2 in series) then please help out with the numbers. Thanks

Battery Power To Utility Setpoint (Default = 23.0) Set to ? (range 22-26)
Utility To Battery Power Setpoint (Default = 28.0) Set to ? (range 24-30)
Battery Boost Charge Voltage (Default = 28.0) Set to ? (range 24-29.2)
Battery Floating Charge Voltage (Default = 27.6) Set to ? (range 24-29.2)
Battery Over Discharge Voltage - Delay Off (Default = 21.0) Set to ? (range 20-24)
Battery Over Discharge Delay Time (Default = 5S) Set to 30S (range 5S-55S) OK (in manual)
Battery Under Voltage Alarm (Default = 22.0) Set to ? (range 20-26)
Battery Discharge Limit Voltage (Default = 20.0) Set to 23.2 (range 20-26) OK (in manual)
Max AC Charger Current (Default = 80A) Set to 20A OK
Battery Under Voltage Recovery Point (Default = 27.0) Set to ? (no range)
Max PV Charge Current (Default = 60A) Set to 20A OK
Battery Fully Charged Recovery Point (Default = 26.0) Set to ? (no range)