Hi all

I'm wanting to add a generator connection to my SNA5000 after going 48 hours with no grid and running out of battery.
What would be a suitable connector for the generator? Needs to mount on an exterior wall and have a lead plugged into it

32A 2P+E should be fine for your existing inverter. Depending on the size of generator and how quickly you want to charge the battery, you could install a 63A plug.

Ordered a 32A 2P+E coupler

Will have a 25A 2 pole breaker between connector and Inverter.

Now a question on earth-neutral bonding. There is a bond on the inverter output. I also have a separate neutral bar as my inverter loads are separate to Eskoms loads.
Would I therefore be correct in saying, that the neutral from the generator to the inverter must not be bonded because there is already a bond after the inverter?

My understanding on EN bonding is limited but I cant see how a bond on the generator side would make any difference as there would be no earth leakage between the generator and inverter.

On 2025/04/14 at 6:18 PM, Bl4d3 said:

My understanding on EN bonding is limited but I cant see how a bond on the generator side would make any difference as there would be no earth leakage between the generator and inverter.

EN bonding provides a path for fault currents. EN bonding at the generator makes sense and officially your inverter bond should be on a relay that opens when running on the generator. You could run with two EN bonds and if there is no nuisance tripping, keep it like that.

On 2025/04/15 at 9:05 PM, frivan said:

EN bonding provides a path for fault currents. EN bonding at the generator makes sense and officially your inverter bond should be on a relay that opens when running on the generator. You could run with two EN bonds and if there is no nuisance tripping, keep it like that.

My bond at the inverter output is permanent due to the separated neutral bars, granted at the time of install, we didnt consider adding a generator.

Understanding the correct way would be to have a relayed bond for the inverter, would having 2 bonds in the system cause a problem? The generator is on an isolator which would only be switched on once the generator is connector. I would be able to make a bond before this isolator, therefore only creating the bond when the generator is running.

@Bl4d3 What generator are you using. Before connecting the generator to the inverter you need to check voltages at L, N E plug outputs. If you have a earth leakage tester you can use it to check compliance. There is a lot of V-0-V generators that should never be used. If you do not get 0v between N to E it is not fit for purpose and not legal to use.

You must get:

L-N 220~230v Ac

L-E 220~230v Ac

N-E 0v~5v

21 hours ago, Bl4d3 said:

Understanding the correct way would be to have a relayed bond for the inverter, would having 2 bonds in the system cause a problem?

I suspect two bonds will cause the earth leakage to trip. You don't have to take the generator earth into the inverter but you need it to protect the cable. All things considered the relay option is probably the safest option.

On 2025/04/20 at 6:50 AM, TaliaB said:

@Bl4d3 What generator are you using. Before connecting the generator to the inverter you need to check voltages at L, N E plug outputs. If you have a earth leakage tester you can use it to check compliance. There is a lot of V-0-V generators that should never be used. If you do not get 0v between N to E it is not fit for purpose and not legal to use.

You must get:

L-N 220~230v Ac

L-E 220~230v Ac

N-E 0v~5v

Using a small 1.2kw inverter generator. It is able to run the essentials such as lights, tv, wifi, but I am planning to upgrade soon.

I'll test the outputs and confirm

17 minutes ago, Bl4d3 said:

Using a small 1.2kw inverter generator. It is able to run the essentials such as lights, tv, wifi, but I am planning to upgrade soon.

I'll test the outputs and confirm

The inverter generators should be spot on no problem there no need to bond.

On 2025/04/19 at 10:22 PM, Bl4d3 said:

My bond at the inverter output is permanent due to the separated neutral bars, granted at the time of install, we didnt consider adding a generator.

Understanding the correct way would be to have a relayed bond for the inverter, would having 2 bonds in the system cause a problem? The generator is on an isolator which would only be switched on once the generator is connector. I would be able to make a bond before this isolator, therefore only creating the bond when the generator is running.

Hi

Having a permanent bond at the inverter will always be a problem if it is connected to the grid at any time, even if you have a separate neutral bar. The reason is that when the grid is present and going through the inverter, it is joined by a relay, which will connect the two separate neutral bars. This is illegal, as now there are two earth neutral, earth bonds (one in the main DB and one at the inverter). When a generator is added at the generator input, it has a neutral earth bond at the inverter when the grid fails through the added connected neutral, earth bond relay.

There should only be one Neutral, Earth bond in a complete circuit.

I cannot see any reason why any inverter needs to have a permanent neutral earth bond if it is connected to the grid, as there should already be a neutral, earth bond for the earth leakage (RCD) to work. You do need a relay connecting the inverter output neutral to the earth when the grid fails, as this allows the series Earth Leakage(RCD) in the circuit to work, as now the two neutrals are disconnected when the relay( not the neutral, earth bond relay) in the inverter opens.

If you connect the generator to the grid input, you need to have a neutral earth bond on the generator side for the earth leakage(RCD) to work properly.

This is my understanding, as I have just connected a generator to an inverter after having some problems. I posted my generator problems under Inverters, Pitfalls when connecting a Generator to a Sunsynk or other Inverter.

4 hours ago, Peter Topp said:

I cannot see any reason why any inverter needs to have a permanent neutral earth bond if it is connected to the grid, as there should already be a neutral, earth bond for the earth leakage (RCD) to work.

The question is if you want to be compliant or safe? A neutral-earthing device will only be compliant if it is SANS/IEC 60947-4-1 certified. A second neutral-earthing point is not compliant but it is safe for the earth leakages downstream.