# Technical question about Victron MPPTs

**URL:** <https://community.victronenergy.com/t/technical-question-about-victron-mppts/58614>\
**Category:** DIY\
**Tags:** mppt\_controllers, offgrid, diy\
**Created:** [29 May 2026 11:52 UTC](https://community.victronenergy.com/t/technical-question-about-victron-mppts/58614 "2026-05-29T11:52:59Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![Fideri](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/fideri/32/2275_2.png) [@Fideri](https://community.victronenergy.com/u/Fideri)\
**Post date:** [29 May 2026 11:52 UTC](https://community.victronenergy.com/t/technical-question-about-victron-mppts/58614/1 "2026-05-29T11:52:59Z")

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Hi everyone,

Simple but technical question: Do Victron MPPTs internally ground the negative output to the battery? I’m specifically asking about the 250/100 and the RS 450/100. According to some technical resources, I shouldn’t protect the negative line with any DC breaker if it is grounded. But if it’s not, I’m fine. I have other options if it is grounded, but they would involve rewiring.

Fideri

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**Author:** ![lxonline](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/lxonline/32/25567_2.png) [@lxonline](https://community.victronenergy.com/u/lxonline)\
**Post date:** [29 May 2026 11:56 UTC](https://community.victronenergy.com/t/technical-question-about-victron-mppts/58614/2 "2026-05-29T11:56:02Z")

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> [@Fideri](#):
>
> neutral output

By neutral you mean the negative?

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**Author:** ![Fideri](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/fideri/32/2275_2.png) [@Fideri](https://community.victronenergy.com/u/Fideri)\
**Post date:** [29 May 2026 11:57 UTC](https://community.victronenergy.com/t/technical-question-about-victron-mppts/58614/3 "2026-05-29T11:57:01Z")

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Yes, sorry about the mixup.

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**Author:** ![lxonline](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/lxonline/32/25567_2.png) [@lxonline](https://community.victronenergy.com/u/lxonline)\
**Post date:** [29 May 2026 12:01 UTC](https://community.victronenergy.com/t/technical-question-about-victron-mppts/58614/4 "2026-05-29T12:01:28Z")

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The MPPT battery negative and pv negative are not isolated. (So they are connected)

> **[7.7. System grounding - 7. Ground, earth and electrical safety](https://www.victronenergy.com/media/pg/The_Wiring_Unlimited_book/en/ground,-earth-and-electrical-safety.html#UUID-63a9c710-66e2-2c63-0d7c-d9345826267b)**
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> Ground or earth provides a common return path for electric current in an electric circuit. It is created by connecting the neutral point of an installation to the general mass of the earth or a chassis. Grounding is needed for electric safety and it...

And off grid are specifically mentioned and should not be connected to a ground.

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<div class="post-metadata">

**Author:** ![Fideri](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/fideri/32/2275_2.png) [@Fideri](https://community.victronenergy.com/u/Fideri)\
**Post date:** [29 May 2026 12:15 UTC](https://community.victronenergy.com/t/technical-question-about-victron-mppts/58614/5 "2026-05-29T12:15:48Z")

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Great. Even my PV is not grounded. Only the MPPT chassis are grounded.

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<div class="post-metadata">

**Author:** ![lxonline](https://dub1.discourse-cdn.com/victron/user_avatar/community.victronenergy.com/lxonline/32/25567_2.png) [@lxonline](https://community.victronenergy.com/u/lxonline)\
**Post date:** [29 May 2026 15:33 UTC](https://community.victronenergy.com/t/technical-question-about-victron-mppts/58614/6 "2026-05-29T15:33:47Z")

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Perfect.

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**Author:** ![system](https://europe1.discourse-cdn.com/victron/original/1X/21a9a7b5db7c6339715f993568736a7053199995.png) [@system](https://community.victronenergy.com/u/system)\
**Post date:** [12 June 2026 15:34 UTC](https://community.victronenergy.com/t/technical-question-about-victron-mppts/58614/7 "2026-06-12T15:34:39Z")

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