Hi all

I need your help! 
 

so I recently purchased a Mecer 3kva inverter with a Hubble Am-4.  Had an electrician come out yesterday for the install. He completed all the connections and upon start up of the inverter the earth leakage trips. He did a test with a multimeter? And found that the short occurs between neutral and earth on the ac input side of the inverter. 
 

He then reconnected the inverter ac input via a wall plug solution on a circuit breaker that’s will always grid tied ( this circuit breaker doesn’t work during load shedding and the inverter doesn’t power it ) and it still trips. 

the inverter works perfectly off battery power and works if the earth is removed on the ac input. 

his assertion is that the inverter is faulty and needs replacing. 
 

advice needed.

 

 

Thanks

 

My guess is that the earth linkage breaker is installed at the input (AC-in port) of the inverter. That will always lead to nuisance tripping, as all inverters have significant current to earth because of the necessary EMI filter capacitors.

Get the earth leakage moved to the output of the inverter. The inverter itself doesn't need earth leakage protection; it's not a consumer device that people interact with all the time. Anyone poking in there needs to know what they are doing.

If you already have an earth leakage device on the output of the inverter, then you can just bypass the ELB on the inverter's input, which might be easier than removing it.

Maybe some causes:

1. Do you have a permanent N-G bond on the AC OUT ? If you do, you probably have two N-G bonds in your system (one from grid and another on AC out). When inverter is in "bypass" or line mode (feeding loads from the grid) the ELB probably senses an imbalance due to this and trips.

2. Do you have AC IN and AC OUT Neutrals combined? 

Do not feed the AC input side of the inverter via an Earth leakage. It will in most cases cause this issue. Place a seperate Earth leakage for the AC output of the loads of any plug points will be attached on the load side. Tap the AC input from the Raw Grid not via a RCD. 

On 2022/11/11 at 6:31 AM, Nivz said:

He then reconnected the inverter ac input via a wall plug solution on a circuit breaker that’s will always grid tied ( this circuit breaker doesn’t work during load shedding and the inverter doesn’t power it ) and it still trips. 

the inverter works perfectly off battery power and works if the earth is removed on the ac input

If I had to guess sounds like mixed neutrals

Live and neutral on inverter output HAVE to be seperated from that which is supplied by grid, in other words a seperate DB for essentials and non essentials

Also just as @Steve87 & @Coulomb (grand master) stated AC IN feed from above earthleakage of non-essentials and AC OUT to above earthleakage  on essentials

Hope this helps in resolving your issue

 

Edited November 13, 20223 yr by SYC