my sunsynk 8kw, has been working very well up until last night. when it suppose to transfer from solar or batter back to grid it trips the earth leakage of  any ideas y? the db . 

Hi 

 I am busy installing the same unit. My question is "Is the earth leakage before or after the  inverter". I believe it can cause some islanding problems (neutral tied to earth) if the earth leakage is before the inverter. In this case you need to install an anti islanding relay. 

This is explained on the Sunsynk  website and the anti isanding relay explanation is also somewhere on this form.

Edited October 6, 20205 yr by Peter Topp

Do you have a relay that bonds the Neutral and Earth in Islanding mode?

13 hours ago, Peter Topp said:

Hi 

 I am busy installing the same unit. My question is "Is the earth leakage before or after the  inverter". I believe it can cause some islanding problems (neutral tied to earth) if the earth leakage is before the inverter. In this case you need to install an anti islanding relay. 

This is explained on the Sunsynk  website and the anti isanding relay explanation is also somewhere on this form.

thanks for your explanation. i having the same issue. do you mind sharing a diagram so that i can give to my electrician since he does not know much about solar systems.

BronCo

Hi 

I will try to explain step by step.

Firstly I have noticed and measured the earthing connectors on the grid input and load output. These inputs are not connected to anything. There is also a place to connect earth on the right hand side of the inverter which is connected to the outside casing inside the connecter box.

Earth and neural need to be connected by the municipality feeding into you db or it needs to be connected where it comes into the db.

The purpose of this is for safety. When you put in a earth leakage it splits the earth  and neutral and if you have a current flowing to earth after the earth leakage it will trip.

Now I do not know how the earths were joined in your setup and where your earth leakage is so I cannot give you a diagram as I do not know your wiring.

If the earth leakage is connected after the inverter then you will need to connect the grid earth and load output earths together or else the earth leakage will not protect you as there will be no mains earth connected.

There will also be a problem if there is a earth leakage before the inverter and one after the inverter.

If there is a earth leakage before the inverter and the earth is not connected to the load output you will also have problems.

A electrician should know when a earth needs be connected to neutral or not.

You do not want the earth and neutral connected after the earth leakage.

There is a connection in the inverter that gives 220vac to switch a relay  which you will need to install to connect or disconnect neural to earth when the inverter switches. This is the anti islanding relay that should be used if necessary.

This explanation is only for a single a single phase setup.

Hi just to add to my comments.

I have just finished my install. The earth connection is on the bottom right which is connected to the chassis. The extra connections on the power connecters  are not used and are for split input power used in the US. You also need to connect an extra earth at the back of the chassis on the right hand side. This is for extra  protection should you loose the power earth.

A anti islanding relay is normal used when you are off grid and the earth and neural are not connected.   The anti islanding  relay would  join the earth and neutral at the incoming power side as it would not be joined if the power is completely cut off.

Do one need an anti islanding relay if the inverter is in front of the earth relays? Why can it just be hard wired to connect the earth of the input to the output?

In my case both the house main db and the essential load db has earth leakages protection. But at my inverter the essential outputs earth and neutral are connected. there is no bridge between the earth of the output and the input earth which makes me worried that the earth spike is not going to provide an alternative path for the earth leakage when the grid is off.