My travel trailer PV system components: Multiplus 3000/24/70, 4 S6-275 AGM Rolls batteries. I am planning the install of a SmartSolar MPPT 100/50 and 2 JKM365M-72-V wired in series.
The SmartSolar 100/50 manual states:
● Battery grounding: the charger can be installed in a positive or negative grounded system. Note: apply a single ground connection (preferably close to the battery) to prevent malfunctioning of the system.
● Chassis grounding: A separate earth path for the chassis ground is permitted because it is isolated from the positive and negative terminal.
As my Multiplus is grounded to the chassis, I would ground the MPPT case to the chassis as well, yes?
● The USA National Electrical Code (NEC) requires the use of an external ground fault protection device (GFPD). These MPPT chargers do not have internal ground fault protection. The system electrical negative should be bonded through a GFPD to earth ground at one (and only one) location.
As this is a mobile application, is a GFPD required?
If so, this appears to be the proper device.
● The charger must not be connected with grounded PV arrays (one ground connection only) You would still bond the PV framing to the chassis, yes?
3.3 PV configuration (also see the MPPT Excel sheet on our website)
● Provide a means to disconnect all current-carrying conductors of a photovoltaic power source from all other conductors in a building or other structure. I take this as a 150VDC / 20A breaker on the positive leg between the PV array and the MPPT and a disconnect on the negative leg between the PV array and the MPPT?
Apparently to Code, the GFPD must not be used as a disconnect. Should the GFPD be wired before or after the PV array Pos. breaker and Neg. disconnect?
● A switch, circuit breaker, or other device, either ac or dc, shall not be installed in a grounded conductor if operation of that switch, circuit breaker, or other device leaves the grounded conductor in an ungrounded state while the system remains energized. Is this in reference to an "uninterruptible" ground to chassis?
In all my research to date, this is the first time I heard of the requirement of a GFPD. Never heard of it on YouTube PV installs.
Any input would be greatly appreciated.