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Just a quick one before taking the inverter back. Recently we got an 12v to 230v inverter but started getting a shock off the casing. Tested it and around 80v but sometimes up to 120v. Is there something that can be done or is the inverter faulty
 
Is the earth in the flex actually connected to the earth bar in the fuseboard.
 

Lucien Nunes

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If you are getting shocks to earth or measuring voltage to earth from the casing of the inverter, something doesn't add up here. It says in the instructions linked by James that the earth pin of the output socket is connected to the case, so if the plug is connected to the DB and the DB is earthed, then the case should be too. The instructions may be incorrect as these cheap units are prone to rapid design changes; do a continuity check from case to DB earth of the inverter's socket, and then onwards to the earth bar in the DB.

On a similar note, is the neutral earthed within the inverter? If not, have you earthed in in the fuseboard? Not doing this won't give you shocks from the case though.
 
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If you are getting shocks to earth or measuring voltage to earth from the casing of the inverter, something doesn't add up here. It says in the instructions linked by James that the earth pin of the output socket is connected to the case, so if the plug is connected to the DB and the DB is earthed, then the case should be too. The instructions may be incorrect as these cheap units are prone to rapid design changes; do a continuity check from case to DB earth of the inverter's socket, and then onwards to the earth bar in the DB.

On a similar note, is the neutral earthed within the inverter? If not, have you earthed in in the fuseboard? Not doing this won't give you shocks from the case though.
I did run a temporary earth wire from the earth in the board to the casing of inverter but this made the lights in the yard come on and off. Would this mean a fault somewhere in the installarion
 

James

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If you are getting shocks to earth or measuring voltage to earth from the casing of the inverter, something doesn't add up here. It says in the instructions linked by James that the earth pin of the output socket is connected to the case, so if the plug is connected to the DB and the DB is earthed, then the case should be too. The instructions may be incorrect as these cheap units are prone to rapid design changes; do a continuity check from case to DB earth of the inverter's socket, and then onwards to the earth bar in the DB.

On a similar note, is the neutral earthed within the inverter? If not, have you earthed in in the fuseboard? Not doing this won't give you shocks from the case though.
Agreed,
The instructions seem to contradict themselves.

One line says for fixed applications then bat -ve must be earthed
Next line says it’s connected to the earth pin and would therefore be earthed from the board.

This is most likely some leakage from the transistors discharging through the heat sink. I would try doing as the nstructions suggest and earth the Bat -ve

The unit might not function correctly if there is a link from earth to N
 

Lucien Nunes

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Although, it says the case is earthed to the output but not necessarily to the DC -ve, so they might want you to connect both to earth externally which is legit. In any event, it should not be possible to get shocks between things that are tied together so something is up.

I did run a temporary earth wire from the earth in the board to the casing of inverter but this made the lights in the yard come on and off. Would this mean a fault somewhere in the installarion
Quite likely, and also likely to be the cause of the shocks. If you don't have the N-E linked, then you have an IT system in which RCDs won't work, so an earth fault on the system allied with a high-resistance rod could cause all sorts of shock hazards without tripping. Test the insulation of the installation, confirm the earthing scheme at the inverter output, etc. etc.
 

suffolkspark

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What's the earth rod at the DB for? Have you staked your inverter down too lol, the inverter I have just requires the 12v battery negative to also be linked to the inverter casing
 
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What's the earth rod at the DB for? Have you staked your inverter down too lol, the inverter I have just requires the 12v battery negative to also be linked to the inverter casing
It the main earth for the yard as there is no electric up there. Just a dB. So without the earth stake there would be no earth on the installation.
Post automatically merged:

You need an earth bond from battery -ve to the earth bar in fuse board.
It's not for a vehicle it's for a yard with no electric.
 

Lucien Nunes

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without the earth stake there would be no earth on the installation
Don't forget, the point to which fault current needs to return is not the earth your rod is in, but the neutral terminal of the inverter which is the source of supply. Earth is just another wire, which on a public supply leads to the earth mat at the substation. As your inverter does not currently have one of those, the 'wire' of mother earth leading away from your rod doesn't go anywhere so won't work. What you want the rod to do is provide a reference for the inverter output, not to earth the installation, because that you can do better with a piece of wire from MET to inverter plug.
 
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Don't forget, the point to which fault current needs to return is not the earth your rod is in, but the neutral terminal of the inverter which is the source of supply. Earth is just another wire, which on a public supply leads to the earth mat at the substation. As your inverter does not currently have one of those, the 'wire' of mother earth leading away from your rod doesn't go anywhere so won't work. What you want the rod to do is provide a reference for the inverter output, not to earth the installation, because that you can do better with a piece of wire from MET to inverter plug.
So what do u suggest to do to stop the casing giving a shock
 

Lucien Nunes

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The fact that connecting the MET to the inverter case seems to cause the inverter to keep shutting down (you mentioned the lights flashing on and off) suggests there may be an existing fault on the installation to real earth, which, via the resistance of the rod, is causing an overload but not a dead short when the circuit is completed by your flylead.

More that that we cannot tell from here. You need to test the insulation of the installation, confirm how / if E & N are connected, etc, as per my post #16. By powering an installation from an inverter (or generator) i.e. your own source of energy, you are taking on some of the responsibilities normally dealt with by the DNO and there are more variables to consider than with an installation supplied from the mains.
 

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