Good day

I am receiving a Victron Phoenix 12/800 inverter this week and need some assistance on how to bond neutral to earth. I want the neutral and earth bonded for proper earth leakage function and also to comply with regulations.

According to the manual the unit has a floating neutral, but if you open the unit up you can bond neutral to earth via a jumper, but from what I've seen online the newer hardware revisions do not have this option anymore. So the only option left is to make this bond outside the inverter.

My problem is that the inverter comes with a Schuko plug so I'm not even sure which side is live and which is neutral. And even if I did, if I connect the Schuko plug the other way around this will be reversed.

From what I've read online an inverter with a floating neutral will measure 230V between live and neutral, and approx. 115V between live and earth, and 115V between neutral and earth. So this is where my confusion comes in.... since both AC outputs are about 115V with respect to earth does it matter which AC output I connect to earth? It seems to me that the one you connect to earth will become the true neutral?

 

Edited January 23, 20223 yr by NDW

Hmm your inverter does not even have an earth connection via the schuko plug 🤨

So basically you want to bond the metal housing and interior of the inverter to the neutral of the grid supply?

There is a way to test which is live and which is neutral at the socket in the wall but that does not always guarantee that the schuko plug will be inserted the correct orientation every time. I would also not put live to earth on your metal housing mistakenly, but perhaps there is something more to be understood here.

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Hmm your inverter does not even have an earth connection via the schuko plug 🤨

So basically you want to bond the metal housing and interior of the inverter to the neutral of the grid supply?

There is a way to test which is live and which is neutral at the socket in the wall but that does not always guarantee that the schuko plug will be inserted the correct orientation every time. I would also not put live to earth on your metal housing mistakenly, but perhaps there is something more to be understood here.

 

Good day.

 

So firstly, the inverter I received has the option to internally to connect inverter neutral and earth, and I have done so.

 

Also, the schuko plug does have an earth that connects no matter how you plug it it.

 

I have everything set up now and I borrowed an earth leakage tester. So with the schucko plug plugged in one way the earth leakage tester states all is normal, and the earth leakage trips at 20mA. With the schucko plugged in the other way, the tester reports neutral reversed, and worryingly the earth leakage won't trip at 20mA or above.

 

I just have to clarify that the earth leakage mentioned above  is downstream of the inverter. If the inverter is bypassed through a transfer switch I use the houses communal db with its earth leakage. Also when the house db is bypassed I join the inverters connected neutral and earth to the house db earth (the house live and neutral are cut off completely). This is as I understand it required by law, and even Victron's own documentation states the an inverter must have its neutral and earth connected to the grid earth when the inverter is running if the grid is disconnected.

 

So it seems to me that Victron shouldn't be selling an inverter with a schucko plug if it causes the above behavior? Am I missing something?

 

 

 

 

 

Edited January 25, 20223 yr by NDW

9 hours ago, NDW said:

So it seems to me that Victron shouldn't be selling an inverter with a schucko plug if it causes the above behavior? Am I missing something?

 

 

 

It seems the same to me. It makes sense for a hair dryer or a vacuum cleaner, but not an equipment that can have its neutral and earth readily bonded. It would make sens then to force the neutral/live wire relationship in the plugtop.

On 2022/01/23 at 9:41 PM, NDW said:

From what I've read online an inverter with a floating neutral will measure 230V between live and neutral, and approx. 115V between live and earth, and 115V between neutral and earth. So this is where my confusion comes in.... since both AC outputs are about 115V with respect to earth does it matter which AC output I connect to earth? It seems to me that the one you connect to earth will become the true neutral?

 

Inverters intended to run appliances direct typically have this arrangement.  They intentionally put plug outputs on the inverter and not a connection point like inverters intended to be connected to your home.  There is no neutral, there are two phase wires 180° apart (so 2 phase).  The earth on those inverters is not floating as you suggest and truly has a 110v potential in respect to the midpoint ("earth").  It is similar to generators with v-o-v configuration and cannot be safely connected to a house.

13 hours ago, NDW said:

So it seems to me that Victron shouldn't be selling an inverter with a schucko plug if it causes the above behavior? Am I missing something?

I'm pretty sure the inverter you have is not intended to be connected to a home.  It is an appliance inverter, so you connect your devices directly to it.

13 hours ago, NDW said:

This is as I understand it required by law, and even Victron's own documentation states the an inverter must have its neutral and earth connected to the grid earth when the inverter is running if the grid is disconnected.

The actual manual that came with your inverter?  Because Victron sell a lot of products.  I have my doubts your exact product is intended for the application you are using it.  The description I see on the web-site is

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Inverters allow you to power domestic equipment - requiring 230V/120V AC - using 'leisure' or 'automotive' batteries rated at 12V, 24V or 48V DC.