Quattro - why install a breaker on AC output?

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James Kinton asked Dec 4, '19

Quattro - why install a breaker on AC output?

Have a single 230v 50hz victron Quattro 10,000VA. AC output 1 is supplying a small AC Panel. The AC Panel has a 63A inlet breaker and RCD, and dedicated breakers for each consumer. There are no other supplies into this AC Panel.

The Quattro manual advises the following "An earth leakage circuit breaker and a fuse or circuit breaker rated to support the expected load must be included in series with output L1, and cable cross-section must be sized accordingly."

In the technical specifications part of the same manual, it advises that there is automatic short circuit, and overload protection. My question is, if these safety features are built in, why must there be a breaker on the AC output side of this inverter??.

Thanks.

inverter current draw ac out 2

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Answer 1 · 2019-12-05T00:14:56Z

Guy Stewart (Victron Community Manager) answered · Dec 05, 2019 at 12:14 AM

A fault is not necessarily a short circuit. So the Quattro may supply enough power to damage wiring, leading to a fire, without triggering short circuit overload protection.

That AC breaker should be sized appropriately that it is sufficient to supply all downstream loads, but will trip before there is possible damage to the wire insulation from overheating.

It also is expected that every conductor has circuit protection, and ideally a point of isolation for troubleshooting, and system maintenance.

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Answer 2 · 2020-03-02T14:04:02Z

Chris Moller answered · Mar 02, 2020 at 02:04 PM

I imagine the published advice relates to a Quattro that is sometimes grid-connected, and sometimes islanded. When grid-connected, fault currents may momentarily be very large, and overcurrent breakers will be essential. When islanded, the Quattro will limit the current, and I'm guessing a 63amp breaker won't trip.

A related question about breakers for branch circuits: I would like to select my breakers so that a short on one branch doesn't dip the voltage for more than a moment on the other branch circuits. Standard breakers rely on the large fault current to trip quickly, but this won't be available in island mode. What is the recommendation? Does Type B (industry standard) trip reasonably quickly, or should all load breakers be Type Z (expensive, hard to find)?

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Answer 3 · 2020-08-13T15:25:27Z

ourrose answered · Aug 13, 2020 at 03:25 PM

How Change Fuse/Circuit Breaker in Quattro 3kw on AC1-Out?

Question: I have a 220v boat with 3kW Quattro. I recently experience a power surge from my shore power and now I can’t get shore power on my boat.

The manual seems to suggest that when one has an overload situation and Charger is not working, one should replace fuses/circuit breaker from AC1-Out or AC2-Out. However, the manual does NOT specify how to change them or how to locate them ( which fuse is for AC1-Out and which is for AC2-Out.

Background: My shore power comes in via AC1-In and my Genset comes in via AC2-In. I know that manual stipulates Genset should be on AC1-In and AC2-In is for shore power. The previous owner installed Quattro and it works so I didn’t change it. We had no problem with Quattro until now.

After the power surge, the inverting function of Quattro still works and Genset charging via AC2-In also works. However, the shore power does NOT.

Our actions: We disconnect the AC1-In wires (ie live neutral and earth) and did voltage test and we saw 240V so we are confident that current flow from the dock to Quattro. However, once we connect the 3 wires back to AC1-In, no shore power.

We even move the 3 wires in AC1-In (Shore Power) to AC2-In Connection and still no shore power.

We also move 3 wires in AC2-In (Genset) to AC1-In as stipulated in manual. We were surprised to find when we did this, Genset also CANNOT charge.

Once we moved Genset wires to AC2-In connection then Genset can charge the battery and produce 240 AC for the boat.

Based on above, can you confirm that:

1) Is changing fuse/circuit breaker on AC1-Out is the right remedy?

2). If so what is the procedure to locate and change the fuses? What are the proper fuse size? 250 ah? (3000watt/12V).

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Peter Buijs - NL commented · Aug 13, 2020 at 04:39 PM

do you really think that someone sits and waits for an answer from dec 04 2019 till now...

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