I am installing a Pheonix 12/1200 Inverter in a vehicle with a floating neutral (factory default) connected to an auxiliary battery recharged from the alternator using a DC to DC charger. It is understood that only one class 1 (earthed) device must be connected to the AC output of the inverter. Can anyone explain the purpose for and how the earth lug on the inverter should be wired in this setup? I have read the manual and Victron’s Wiring Unlimited book, but I am still unsure.
Hi Tim and welcome.
Don’t know if this below helps?
Page 12 below.
Dave.
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Hello Dave, thank you for your response. I intend to leave the inverter floating. I am looking for confirmation that the inverter’s earth lug in that setup is attached to the case and is isolated from the AC output. In which case I assume it is to be used to dissipate DC current in the vent of a fault inside the inverter. Currently I have attached it to the vehicle chassis with a cable one size down from the battery input as per the Victron manual.
Hi Tim, did you see this? Hope it helps.
Victron Phoenix Inverter AC Ground/Earth? - DIY - Victron Community
Dave.
Thank you Dave.
That link appears to refer only to AC grounding. I am not grounding the AC side as I intend to leave it floating.
No earth is connected for a floating ‘PE’. Neither on the vehicle nor on other metal superstructures. ‘Floating earth’ … as you have already written, you may only connect one device here to ensure 2nd fault safety. Operation outside the vehicle is also permitted here …
Hello Steffen,
Thank you for your response. For the avoidance of doubt, can you tell me where the DC earth connection should be made. i.e. to the vehicle chassis or the auxilliary battery neutral (or could it be either)?
The negative of ALL batteries should always be connected to the chassis in order to trigger the fuse in the event of cable damage.
However, you must always check the system configuration to see whether the negative of the batteries may also be connected in this way !!! There may be systems that have to be galvanically isolated from each other. That is why isolated DC/DC converters are used … The vehicle battery should of course always be connected to the chassis.
Are you using a isolated DC/DC Charger ?
The auxiliary battery is connected to the chassis via a non-isolated DC to DC charger.
then everything stays the same … as long as you don’t want or need to install a shunt to measure anything on the two batteries … simply connect the negative leads to earth from the chassis … done … and the 230V without earthing … for the use of one device
OR
the protective conductor from the 230V to the chassis AND the short-circuit bridge between N and PE … then you can use more devices in the vehicle … but then you need residual current protection
Thank you for your input - it is much appreciated.
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