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Crossover or bypass switch for inverter.


Crankshaft

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I have a Victron Multiplus-2 3000 currently in service in UPS mode.

Is it a good idea to add a crossover switch allow me to 'bypass' the inverter in the event of equipment failure, etc?

I started looking into the subject, but bypass switches are also mentioned, and now what seemed a simple exercise it looking a bit more complicated.

Any help will be appreciated.

 

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1 hour ago, plonkster said:

A bypass switch is non-negotiable afaic. So you can bypass the inverter when working on it. Married people will agree with me. The long haired bipeds don't like outages 🙂

Can one use a 2-pole on-off-on crossover switch for this, or is there a special bypass unit?

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I found this bypass schematic from Victron.

Is that a standard 2 pole crossover switch?

Thinking about the neutrals:  My house has been separated into 2 circuits - one for UPS operation, and the other non-critical (and heavy) loads on another.  This means that each circuit has it's own neutral bar and earth leakage.

I'm assuming that I will require a 4 pole crossover switch to handle the neutrals as well.

 

 

Bypass.JPG

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3 hours ago, Crankshaft said:

I'm assuming that I will require a 4 pole crossover switch to handle the neutrals as well.

Yes. Victron's line diagrams typically simplifies things and draws only one side, but of course you need a double pole changeover. 

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You get the big sort aka gen mains bypass and then a minute mcb type.

I recommend the big type as it is more wife friendly.

Get an electrician to install it . About R1200.

I use mine all the time when I use the borehole pump as it pushes the inverter to 100%.

With two leds on it it is easy to keep track of where the power is coming from.

Edited by Johandup
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  • 4 months later...

I'm yet to fit my bypass or crossover switch.

Do I get a 2P and utilize a cross-over circuit, or a 4P and do a full bypass circuit.

My common sense tells me a 4 pole switch that will completely remove the inverter is better.

But, this can also be achieved with an isolater at the inverter input.

Any comments?

 

 

 

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I plan on using a Hagar SF463 , it is four pole, so that I can use it for both the AC1 out and AC2 out on the Easysolar II, will install it in a surface db next to the inverter, also will install a double pole circuit breaker on AC input to completely isolate the inverter

Edited by Tariq
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16 hours ago, Crankshaft said:

But, this can also be achieved with an isolater at the inverter input.

I would go with this option (that is what I did actually). I also don't use an isolator, I use a breaker with overcurrent protection, so that the cable to the inverter input is also protected.

The reason for using a separate breaker, is so that I can move my loads to the grid (eg to do maintenance, firmware updates, etc), but still have AC available on the input of the inverter. This means I can charge the batteries using the inverter/charger even though my loads are on the grid.

Also, I have a Carlo Gavazzi grid meter installed and the Multi can feed energy into the input to cancel out my loads. So running all my loads on the grid and still using the Multi to feed in energy is a valid mode of operation for me (that I will sometimes use), so again, it is useful to not have these two things controlled by the same lever.

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5 minutes ago, plonkster said:

I would go with this option (that is what I did actually). I also don't use an isolator, I use a breaker with overcurrent protection, so that the cable to the inverter input is also protected.

The reason for using a separate breaker, is so that I can move my loads to the grid (eg to do maintenance, firmware updates, etc), but still have AC available on the input of the inverter. This means I can charge the batteries using the inverter/charger even though my loads are on the grid.

Also, I have a Carlo Gavazzi grid meter installed and the Multi can feed energy into the input to cancel out my loads. So running all my loads on the grid and still using the Multi to feed in energy is a valid mode of operation for me (that I will sometimes use), so again, it is useful to not have these two things controlled by the same lever.

Good reasoning.  This is the route I will go.

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2 minutes ago, Crankshaft said:

Good reasoning.  This is the route I will go.

Also, then you can buy the cheaper 2-pole switch. The SF240 for example. @Tariq, I was wondering why you're going with the 4-pole one... figured you probably had good reason, like maybe 40A wasn't enough for you 🙂

 

Edited by plonkster
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11 minutes ago, Tariq said:

going to draw over over 10 kilowatts from the 3 kilowatt inverter

Not outside the realm of possibilities. I have an older Multigrid inverter with a 50A transfer switch. If I wanted to use the full capacity (that's the point of using a hybrid inverter, the difference can come from the grid), I'd have to go with a 63A changeover. I don't think Hager makes a 2-pole of that size, so I'd have to use the larger 4-pole one and use only half of it.

The other reason for using a 2-pole, of course, is that space is a perpetual problem in most distribution boards. When I still used an older Multiplus (before I had the ultigrid) I also had to fit a Ziehl anti-islanding switch, which takes up 5 DIN spaces, and a contactor (of which the most cost-effective option was a 3-pole, using only two of them)... and then on top of all that I had to fit a changeover, a main switch on the inverter output, and an RCD as well. By the end of all that it was simpler to just fit a 2x18 additional DB board to house all the extra stuff... 🙂

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Just kidding about the 10 kw, @plonksterespecially when you mentioned about why I was using a 63 amp switch, using 30 amp circuit breakers on AC 1 and AC 2.

    Am going to try to figure out what Plonkster and Crankshaft are talking about on their rigs for changeover setup 

Tariq 

 

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Actually, if Hager made a 3P unit then that is all you need. I have the Hager 4P change-over installed and I went and got myself the ACDC 3P changeover. Knowing the quality might be a bit less I went for the 125A version but you need a crowbar to switch it over so never installed it. Below is how mine is wired based on your diagram keeping in mind the Neutrals in the Multi is connected together internally. Yes you lose some DB space with the 4P but you have that one open slot available IF you ever want to split the Neutrals BEFORE the inverter and run your heavy loads directly from the grid and only critical loads on ACOut1. I left mine like yours as it's not worth the effort and works perfectly fine as-is except my GX only shows a combined load output and not the split output when done the other way. 

image.png

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5 hours ago, Ingo said:

my GX only shows a combined load output and not the split output

That is normal. The Multi/Quattro does not have separate current sensors for AC-Out-1 and AC-Out-2. It has only one for the combined output. So "non-essentials" on AC-out-2 also show up on the output of the inverter. Well, unless you have one of the handful earlier hardware revisions of the MP-II that had it wired to the input just past the input current sensor.

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Morning all, as previously mentioned, I am using the SF463 4 pole changeover switch, would there be any advantages to using two SF263’s , so that that the two outlets AC 1 and AC 2 on the Multiplus II can be switched on or off individually 

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3 hours ago, Tariq said:

Morning all, as previously mentioned, I am using the SF463 4 pole changeover switch, would there be any advantages to using two SF263’s , so that that the two outlets AC 1 and AC 2 on the Multiplus II can be switched on or off individually 

Well, let's look at cost. em.co.za shows the SF463 at +-R1400 ex VAT. 2 x SF263 would be R530 each, so there is a R350 cost saving possible. Overall required space remains the same.

If you don't need the 63A capability, you can go for 2 x SF240. I can't find that one on em.co.za, but as I recall they are around the R250 mark, and two of those take up only 4 x DIN spaces. Cost and space advantage (but only if 40A is enough).

Finally, is there an advantage to having the outputs separately switchable? I can think of one possible use: You may want to move loads from AC-out-2 to the grid side, but leave the other essentials on AC-out-1. I don't really see that as compelling, but you'll have to decide how likely you are to need that.

Edited by plonkster
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If I had that extra Neutral in my DB like you have I would run it Grid Parallel and not use ACOut2 at all. It will save on the 4P C/O and some DB space, display separate AC Consumption on my GX (which I like) and also fix my pet-peeve of 'something' I can't get fixed on ACOut2.

Like @plonkster said, you have to decide which works best for you, you have all the building blocks for a good system.

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Just saw on em.co.za that the SFT 440 is R726 ex vat, so that should work fine, also would be easier for the wife to flip one changeover switch, then to remember two individual switches.

ps :- Have three phase supply, with each phase having a CoCT breaker rated 35 amps, am using one phase dedicated to the Easysolar, items like geyser, pool pump hooked up to AC 2 to utilize pv power as much as possible

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2 hours ago, Tariq said:

easier for the wife to flip one changeover switch, then to remember two individual switches.

You could always replace that 4 pole change-over switch with two x 2 pole change over contactors, than switch the contactors with your phone via sonoff control, much easier and no need to ever manually switch levers. Cost will be about the same as the 4pole c/o switch. Thats what I done and works great. 

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