Our new travel trailer arrived with the PV+ having continuity to the chassis ground. I say this is a wiring fault (warranty). My dealer is open-minded but he is suggesting the wires are mislabeled, and that having a (re-labeled) PV Minus grounded to the chassis (and therefore the negative battery terminal) is OK. My dealer does not use Victron on his solar installs. Am I correct that when using a Victron MPPT 100/30 MPPT controller the solar circuit should “float” - i.e. Neither PV+ nor PV- should be grounded to the chassis? If I am correct is there documentation somewhere that states this? Thanks in advance.
No. Both PV negative and Battery negative are common with most Victron MPPTs. Only the big MPPT RS450 have full isolation between PV and Battery.
Update from me (the OP). When I posted my question on the Victron Forum the system thankfully pointed me to Section 7.7 “Grounding” - which explicitly states PV Plus and PV Minus should NOT be grounded. I believe I have my answer and the necessary documentation.
Yes, you should not intentionally ground the PV positive or negative. Only the frames if thats necessary.
If the battery negative is already grounded (which it normally is) then automatically also the PV negative will be grounded (because the two are common on the MPPT)