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cdav3435 asked

RCD Design for a Parallel MultiPlus Installation

I'm currently designing an off-grid system with 2x MultiPlus 120/3000/70. The AC-1 outputs will be tied in parallel before feeding the main house panel. The MultiPlus manual states that an RCD is required on the AC-1 output, but I'm unclear on whether each MP requires a separate 75A RCD or if a single 150A RCD should be used to protect both.

My gut tells me that separate RCDs won't work because the current/load on each MP may fluctuate, but I've not had much luck finding a 150A RCD - it seems these are rare above 100A. I've read through the MP manual, Wiring Unlimited, the parallel/3phase install guide, and the Victron Professional site, and haven't found a good answer.

Thanks in advance for any insight :)

multiplus in parallel
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2 Answers
wilm avatar image
wilm answered ·

Why a 75A RCD? A Multiplus 120/3000 can handle 3.000W. Practically, we are talking about 2400W each, which is for 120V 20Amps. So a RCD with 40Amps is enought for that job.

Best,
Wilm

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cdav3435 avatar image cdav3435 commented ·

Inverter capacity is 25A, plus 50A passthrough from a generator.

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Michelle Konzack avatar image
Michelle Konzack answered ·

If you want to use the full power including pass-trough, then a 150A is neccesary.

You need only one for the installation

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