Hi everyone,
I have a working Victron system, no issues.
As a backup, I plan to switch ground using L3 of a 3-phase system even though both my Victron system and mains are single phase. Weirdly, I can’t get a single phase changeover switch (online is not an option). I can only get a three phase changeover switch with L1, L2, L3, and N. That means I can’t see a way to switch ground from my Victron system or from mains. So I am thinking of using the empty L3 for switching ground automatically whenever the two sources are switched.
F.
With the 3-phase changeover switch, however, the N is also changed over. Otherwise such a switch makes no sense.
So you could definitely use the L3 … you would then use L1 and L3 … and leave L2 free
As you only have a 1-phase system, you would not need a ‘leading’ N.
You absolutely need a changeover switch that switches via ‘0’ … i.e. once via an empty position so that the switching contacts remain potential-free for a longer period of time before they are switched on again. Otherwise, in the worst case, this can lead to a defect
Ground is ground.
I can’t imagine it ever being a good idea.
What happens if the contact in the switch fails - ground is defeated?
Are you sure that is to code?
The situation is not ideal. I’m thinking that’s less bad than not having ground at all full time. As for codes, they don’t exist where the system is. The individual concerned has to figure out everything (and God for us all 
).
You are right. L2 will stay empty. N will also be switched. So live/line will go to L1, ground to L3, and neutral/common to N.
But there is no 0 position, is there?
To switch over, you would have to switch the changeover switch voltage-free beforehand with another 2-pole switch … then switch over without danger
I forgot about that. Luckily, the switch has position 0, in addition to 1 and 2.
In that case don’t switch ground. For saftey reasons ground should not be interrupted.
And in a three phase with a changeover also neutral generally should not be.
That’s is also an option. Having ground permanently connected to my quattro. I can’t rely on the mains earth because I have no idea what happens upstream.
But I’m confused about neutral. I thought that ideally, live, ground and neutral should all be switched?
Neutral not normally if you have three phase supply. Loss of neutral reference means line to line voltage only.
Victron reference neutrals for safety mechanisms like the ground relay.
Is your system using more than one phase? If it is dont switch neutral either. It should remain unbroken (except for individual switching on the inverters in case a unit needs to be isolated and removed)
My supply is single phase but I plan to use a three phase changeover switch on it.
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Are you using it to change between phases?
No. Between solar and mains, both single phase.
Maybe you need to explain then the pupose of the changeover switch you want to install.
Just for my loads to use either solar (mostly) or mains (sometimes). Normally I should use a single phase changeover switch but for various reasons, that is not available.
So as a bypass? For two outputs or just one?
Just switch the line and neutral (which is common for two the outputs)
Your ground should be central in your DB and tied to neutral anyway.
That works. As a clarification, I have 2 single phase sources. Both have their own live, ground and neutral. But my switch has three lives and one neutral for each source.
I have never seen a three phase change over have two neutrals. Do you have a picture of the switch?
Yes. Top front from left to right L1, L2, L3 plus N for one source; Top back not fully visible from left to right L1, L2, L3 plus N for another source; bottom L1, L2 and L3 plus N for loads.
Some have 8 terminals. Others including mine have 12 (that’s what my electrician tells me). I can’t work out the difference.
The switching of neutral will be the difference.
Some will just switch all line no neutral.
When you switch over check if is break and make for the neutral.
Iwould just switch line and neutral for both sources and find a common place to ground.