Where to connect Inverter Earth/Ground cable

[CAPTAIN FANTASTIC]

What is the best place to connect the earth/ground cable from the inverter body? to Battery negative?
I use the inverter (1500 watt pure sine wave) as stand alone unit, to plug fridge etc; it is not connected to shore power.

 

[VicS]

What is the best place to connect the earth/ground cable from the inverter body? to Battery negative?
I use the inverter (1500 watt pure sine wave) as stand alone unit, to plug fridge etc; it is not connected to shore power.

To the vessel's main earthing terminal which should itself be connected to the hull of a metal hulled vessel or to an external grounding plate in the case of a non conducting hull.

The earth terminal on the inverter is not just an earth connection for the case . It should be connected internally to the output circuit earth conductor and to one of the live output conductors to create the neutral.

A standalone inverter which is not intended to be connected to the shorepower system may have a pseudo centre tapped earth and two live conductors neither of which is earthed to form a neutral.

 

[PaulRainbow]

The earth terminal on the inverter is not just an earth connection for the case . It should be connected internally to the output circuit earth conductor and to one of the live output conductors to create the neutral.

Here we go again, more inverter drivel.

Anyone reading this dangerous drivel, please ignore it.

 

[CAPTAIN FANTASTIC]

Thank Vics for the reply; I will check the inverter to ensure that the earth terminal is connected internally to the earth conductor. The boat is grp and there is no external grounding plate.

 

[PaulRainbow]

What is the best place to connect the earth/ground cable from the inverter body? to Battery negative?
I use the inverter (1500 watt pure sine wave) as stand alone unit, to plug fridge etc; it is not connected to shore power.

Basically, anything that's in contact with the water, the 12v negative may not be. If you don't have a metal hull or a grounding plate, (most of us don't have either) a hull anode works well.

 

[CAPTAIN FANTASTIC]

Here we go again, more inverter drivel.

Anyone reading this dangerous drivel, please ignore it.

Where do you think I should be connecting the earth cable to?

 

[PaulRainbow]

Thank Vics for the reply; I will check the inverter to ensure that the earth terminal is connected internally to the earth conductor. The boat is grp and there is no external grounding plate.

Please, please, do not make any internal changes to the inverter unless you absolutely, 100% certain, know how your particular inverter works and that you know what you are doing.

 

[PaulRainbow]

Where do you think I should be connecting the earth cable to?

See post #5

 

[CAPTAIN FANTASTIC]

Basically, anything that's in contact with the water, the 12v negative may not be. If you don't have a metal hull or a grounding plate, (most of us don't have either) a hull anode works well.

Unfortunately, the anodes are located on the prop shaft close to the propeller.

 

[PaulRainbow]

Unfortunately, the anodes are located on the prop shaft close to the propeller.

Does the prop shaft have electrical conductivity with the gearbox ?

 

[CAPTAIN FANTASTIC]

Does the prop shaft have electrical conductivity with the gearbox ?

Yes, there is a conductivity.

 

[PaulRainbow]

Yes, there is a conductivity.

You can connect there then.

 

[CAPTAIN FANTASTIC]

That's great, thanks for the replies. Therefore, as the battery negative is connected to the engine and the inverter is connected to the battery negative, I could connect the earth from the inverter directly to the inverter negative ; am I correct?

 

[VicS]

Here we go again, more inverter drivel.

Anyone reading this dangerous drivel, please ignore it.

There is nothing dangerous in my post

The inverter earth should be connected to the main earthing point. That's not dangerous that is how it should be connected. Moreover the Victron instructions say it should be connoted to the metal hull or external ground plate,

internally the output PE conductor should be connected to the chassis/ case ( earthed as above) as should the "neutral" conductor . That;s not dangerous that is how how it should be . A centre tapped configuration, rather than a neutral earth bonded configuration may be acceptable for a stand alone inverterI If an RCCB is to be used an earth bonded neutral is required

The correct internal connections may already be made or it may be necessary to make them during installation. Different brands and models vary and may include provision for wiring either as centre tapped or earthed neutral.

 

[VicS]

That's great, thanks for the replies. Therefore, as the battery negative is connected to the engine and the inverter is connected to the battery negative, I could connect the earth from the inverter directly to the inverter negative ; am I correct?

This is a poor substitute for connection to a proper external ground plate.

You do not have a hull anode but if you did you should not use it as an alternative to a ground plate . It would have been fitted to provide cathodic protection to underwater structures otherwise vulnerable to corrosion

 

[PaulRainbow]

This is a poor substitute for connection to a proper external ground plate.

You do not have a hull anode but if you did you should not use it as an alternative to a ground plate . It would have been fitted to provide cathodic protection to underwater structures otherwise vulnerable to corrosion

Pure and utter rubbish, please stick to what you know and stop posting this drivel.

 

[PaulRainbow]

There is nothing dangerous in my post

You said:

The earth terminal on the inverter is not just an earth connection for the case . It should be connected internally to the output circuit earth conductor and to one of the live output conductors to create the neutral.

You're suggesting that people open up the inverter and make internal connections, that's very dangerous.

You have now added:

The correct internal connections may already be made or it may be necessary to make them during installation. Different brands and models vary and may include provision for wiring either as centre tapped or earthed neutral.

You need to stop this, the mods should remove these posts before someone is injured or killed.

The inverter earth should be connected to the main earthing point. That's not dangerous that is how it should be connected. Moreover the Victron instructions say it should be connoted to the metal hull or external ground plate,

Does you boat have a metal hull, or external ground plate? mine doesn't and neither do most of the boats out there, external ground plates are extremely rare.

This was covered in the last inverter thread, where i posted evidence from multiple sources regarding the Earth connection.

At that time, when asked, you said if you needed an inverter fitting you would pay a qualified electrician, yet you somehow feel qualified to post on here telling everyone else how they should fit their, including dangerous advice regarding internal connections.

Again, please stick to what you know and stop posting highly dangerous and incorrect advice.

 

[rogerthebodger]

Yes hear we go again.

1) For a metal boat Vic is correct except if the metal case of the inverter is connected internally or externally to the neutral output of the inverter and thus to the main protective earth there is no need for a second connection from the metal case to the hull of a metal hull.

2) The function of a earth spike connection to ground is to provide a secondary path is the main wired earth fails of there is a path through a person standing on the conductive ground.

3) On a GRP hull/deck which is insulated from the water would no allow a path of the current to the water. This is just like any one standing on an isolated stand or rubber mat and touching a live conductor, all that would happen is you hair would stand on end.


4) The earth connector on a metal hull is very important a all stainless steel is conductive to the hull.

5) There are 2 possible positions of any GI . Paul says it must be inline with the incoming shore power earth connector then to the boat earth wire and the hull or earth plate. This is based on industrial normal practice. The issue I have is if the GI fails the incoming earth line would be disconnected from the boat hence the importance of the GI to fail short circuit. If you have a simple back to back diode GI these are not fail safe.

6) I have put my GI between the incoming earth line and the boat hull/ground plate. If the GI fails the secondary earth via he water will be removed but the main external earth will still be intact. This is why its important to have some indication of loss of primary earth as I have with a neon between live and earth. This neon must be on for an effective primary earth.

This is a very emotive subject and needs considering in light of the exact arrangements of your boat and its impossible IMHO to have a one size fit all configurations.

At one time the industry standard for connecting anodes together and to an earth plain but proper analysis proved this to be incorrect and depending on the exact arrangement of the boat.

 

[PaulRainbow]

No one is talking about GIs Roger.

That's totally irelevent to an inverter earth.

 

[rogerthebodger]

No one is talking about GIs Roger.

That's totally irelevent to an inverter earth.

I only spoke about GI's in the last 2 items what are you comments on the first 4 items.

The position of the GI is very important to the effective of a protective earth and the reliability of the earthing of a mains circuitry

Don't evade the points I made