question

bennetimo avatar image
bennetimo asked

Hardwiring Victron Phoenix inverter, is a dedicated earth wire needed from consumer unit to chassis?

When using the Victron Phoenix hardwired into a consumer unit in a van with an RCD and MCB, should the consumer unit itself have a dedicated earth wire run from it back to chassis?

This is with the N-E bond jumper set inside the inverter so that the RCD will function correctly, and no shore power so the inverter is the only thing supplying AC power.

There are several Victron wiring diagrams, e.g. https://www.victronenergy.com/upload/documents/VE-direct-drawing-with-Phoenix-charger-12-50-1-inverter-375W-Li-Batt-smallBMS-MPPT-100-30-Orion-Tr-smart.pdf , which do not show a separate earth wire from the earth bar of the consumer unit back to the negative bus bar/chassis. But the inverter case ground is of course connected back to the negative bus bar.


I know that the AC out earth pin from the inverter is connected to the case internally, and the case itself it grounded back to the negative bus bar (as shown in the diagram above too). So there is already a path for the earth from the sockets to go back via the earth bar in the consumer unit, back through the earth wire in the cable going back to the inverter, to the inverter case, and then ultimately to chassis.

My question is should there also be a dedicated earth wire run from the consumer unit back to the negative bus bar/chassis? Most installs/wiring diagrams I've seen show the inverter case being grounded, but also the consumer unit itself being directly earthed to chassis (e.g. https://www.vunked.co.uk/wiring-a-campervan-inverter/). This seems duplicated/redundant, and is not shown in the victron diagrams, so is it not needed, or should it be added for best practice? Potentially this differs between different inverters/manufactures depending on if the AC out earth is connected to the chassis internally or not too.

Any thoughts?

Phoenix Inverter
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2 Answers
Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

There is no definitive answer on best practice for earth wiring, It entirely depends on your local rules and requirements. So it's very common to get directly contradictory diagrams and information.

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bennetimo avatar image
bennetimo answered ·

Thanks for the response! Yeah it is definitely dependent on local rules, I should have added I'm in the UK. From speaking to a few people it seems over here that even though the earth is provided via the inverter a separate earth cable should still be added direct from the van chassis to consumer unit to satisfy BS 7671 721.411.3.1.2.

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