Max current out of Multiplus II 48/5000 50/70

DIY
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1

Since the AC connections of the Multiplus II 48/5000 50/70 are limited to 16sqr mm maximum conductors how can they safely transfer the rated AC 50A input said to be possible even ignoring the DC-AC conversion capability which would be about 22A more? I think 16sqr mm (#6) copper wire should not be designed to exceed 35A.

The answer I expect will be it can’t but I can’t find any details in the documentation on the matter other than to say the input should be current limited in accordance with conductor capabilities.

I have seen the Victron circuit for 3phase that uses a parallel supply path to add the high current capability of a linked generator but was hoping to avoid the cost of the $ks needed to switch in and out high currents when required.

2

@rae I think 16 square mm cable can carry about 70amps. I am not sure what problem you are solving or if that information helps at all.

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3

Agree with the above.
16mm is easily good for the amps specified - dependent on installation scenario.
Also MP 2 has 3no. AC connections - (ACin can be used for bidirectional of electricity flow), all allowing same dimension cable.
Spec sheet for the UK specifies AC screw connections as 13mm2, which allows for commonly available 10mm2 cable - good for 60a+.
Design system accordingly within given documented specifications and all should be good.

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4

If you are using fine strand cable 16mm² is enough.

5

16mm^2, copper wire, can carry almost 80A, on the following conditions:

  1. Ambient temperature 30 deg.C,
  2. Maximum continuous loading temperature of conductor of 70 deg.C
  3. Clipped direct 3 or 4 cables.

For 50A, it’s enough 10mm^2, (#7)

Here is an interesting material for read about sizing conductors:

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Thanks Alex, Trevor, 1234enough and LX for adding your confidence to using the available wire size. I have a large kiln that draws 50A 3phase and a generator that supplies the same through AC-In to my Multiplus-II’s. I only have one 35sqr mm cable running to the kiln and house services and don’t think I’m allowed to parallel the out-1 and out-2 circuits so all power will be through out-1’s. I suppose I will try making the out 1 #6 run using fine strand wire which is not so common in Australia and as short as possible. Then just check it throughout the 1st few days …

7

Thanks for the confidence building replies. Perhaps the connections have been upgraded because the multiplus-II Rev-05-09/2022 documentation that came with my units says the 230 VAC-connections are 16mm2 (6 AWG).