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Laurens D avatar image
Laurens D asked

Earth leakage Circuit Breaker for AC out

I'm designing the AC side of the system for my multiplus ii, I was wondering what was needed or not; the grid side has a leakage circuit breaker and a normal circuit breaker.

However, when setting the system up we also have AC OUT however I'm not fully sure if it's suggested to have something in between or not.

In the examples I see a easy overview but that's directly to the 'wall', I was thinking about adding an normal circuit breaker but I was wondering, will I need to have an earth leakage circuit breaker also?

Any suggestions would be nice :-) Thanks!



edit: Likely worth to mension; this is for a home system where it is connected to a grid (no solar).

Multiplus-II
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Phil Gavin avatar image
Phil Gavin answered ·

Yes, for a typical domestic installation, you will require earth leakage protection. This is the protection that saves lives.

This will require that your power source is earthed; there must be a low impedance earth fault return path for fault current.

Type AC Earth leakage is redundant for modern domestic load profiles, although still sold. (Cheap)

Type A is appropriate for the modern domestic load profile. (Pricey)

Type B is stipulated when there is no galvanic isolation between the DC side and the AC side. (Expensive)

LF Victron inverters satisfy this requirement. However, the majority of PV inverters do not. So AC-coupling a PV inverter would still require the system to have a Type B earth leakage*.

*( Unless the PV inverter manufacturer confirms an isolated design, which I have only seen SMA do).

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Laurens D avatar image Laurens D commented ·

Thank you! I do not live in a place that can have PV's unfortunately so it's a bare minimum.


I was not sure whether it was required, but I assumed it was because the inverter can give out power; so it was likely needed, thank you I bought a Type A earth leakage protection; better safe than sorry!

To avoid miscommuncation; those earth leakage can go to the normal earthing right, or does this have to be a separate earth point from your normal AC?

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Phil Gavin avatar image Phil Gavin Laurens D commented ·

This is a site-specific question, that the source ( whatever it is) must be earthed is clear. How it is achieved and proving the quality thereof should involve a local professional.

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