# 3 X Multiplus II Changing from single unit to 3 phases system

**URL:** <https://community.victronenergy.com/t/3-x-multiplus-ii-changing-from-single-unit-to-3-phases-system/26902>\
**Category:** DIY\
**Tags:** beginner, vrm, cerbo\_gx, multiplus-ii, ess\
**Created:** [28 March 2025 15:52 UTC](https://community.victronenergy.com/t/3-x-multiplus-ii-changing-from-single-unit-to-3-phases-system/26902 "2025-03-28T15:52:39Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Camomille](https://avatars.discourse-cdn.com/v4/letter/c/d07c76/32.png) [@Camomille](https://community.victronenergy.com/u/Camomille)\
**Post date:** [28 March 2025 15:52 UTC](https://community.victronenergy.com/t/3-x-multiplus-ii-changing-from-single-unit-to-3-phases-system/26902/1 "2025-03-28T15:52:39Z")

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Hello, I have installed 3 Multiplus II They are connected to AC using neutral and one different phase each. A network cable is is passing in and out VE busses from 3rd to 1st and to Cerbo GX.  
No problem when only first Multi is on. I have error #3 or #17 when an second one is powered on.  
Devices list in the VRM only shows Cerbo and the first Multiplus configured as “single unit”  
Is there any way to modify this “single unit” config using VE Config editor or do I have to wait untill I receive a MK3-USB interface?  
Great thank in advance.  
Greetings from Belgium.  
Camomille

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**Author:** ![MikeD](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/miked/32/1522_2.png) [@MikeD](https://community.victronenergy.com/u/MikeD)\
**Post date:** [28 March 2025 22:30 UTC](https://community.victronenergy.com/t/3-x-multiplus-ii-changing-from-single-unit-to-3-phases-system/26902/2 "2025-03-28T22:30:52Z")

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I think you’ll need to wait for the Mk3.

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**Author:** ![M\_Lange](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/m_lange/32/16_2.png) [@M\_Lange](https://community.victronenergy.com/u/M_Lange)\
**Post date:** [29 March 2025 05:16 UTC](https://community.victronenergy.com/t/3-x-multiplus-ii-changing-from-single-unit-to-3-phases-system/26902/3 "2025-03-29T05:16:42Z")

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To make the initial configuration of more than one VE.Bus device you need a MK3 Interface.

> **[Parallel, split- and three-phase VE.Bus systems \[Victron Energy\]](https://www.victronenergy.com/live/ve.bus:manual_parallel_and_three_phase_systems)**

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**Author:** ![zedamoca](https://avatars.discourse-cdn.com/v4/letter/z/5fc32e/32.png) [@zedamoca](https://community.victronenergy.com/u/zedamoca)\
**Post date:** [3 May 2025 15:09 UTC](https://community.victronenergy.com/t/3-x-multiplus-ii-changing-from-single-unit-to-3-phases-system/26902/4 "2025-05-03T15:09:07Z")

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and 2 single units, is it possible?

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**Author:** ![Ted.Spancer](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/ted.spancer/32/24742_2.png) [@Ted.Spancer](https://community.victronenergy.com/u/Ted.Spancer)\
**Post date:** [23 May 2025 08:31 UTC](https://community.victronenergy.com/t/3-x-multiplus-ii-changing-from-single-unit-to-3-phases-system/26902/5 "2025-05-23T08:31:23Z")

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Sadly you need MK3 Interface just to change “Phase mode” (1-phase, 2-phase/split, 3-phase) on units, after that you can use VRM remote upload/download. Also remember to disconnect Cerbo when switchig modes.