Classic Manual Rev L
18 | P a g e 1 0 - 0 0 1 - 1 R E V L
Grounding
Chassis Grounding
In all installations the Classic chassis should be connected to ground. For systems with a battery
breaker sized 60A and smaller, #10 AWG (6 mm
2
) copper is generally sufficient. For systems with a
battery breaker sized 100A and smaller, #8 AWG (10 mm
2
) copper is required. For grounding
conductor requirements on your specific installation, please consult your local electrical code. The
chassis grounding terminal is in the upper right corner of the electrical connection compartment.
DC System Grounding
The Classic is designed to work with negative ground, positive
ground, or ungrounded power systems. In negative ground
systems, DC negative may be connected to ground either
externally or by using the Classic’s internal grounding jumper,
shown in Figure 10. The internal grounding jumper should
only be installed when the Classic’s GFP is enabled. When the
chassis ground point is connected to earth ground and the GFP
jumper is installed, a DC negative to ground bond exists.
In a positive ground system or for an intentionally ungrounded
system, the GFP jumper must be removed.
Also note that with positive ground there will be items
still referenced to battery negative that can complete a
short circuit of the battery bank. These items include, but
are not limited to, the USB Cable and RS232 serial data lines.
DC GFP (Ground Fault Protection)
The Classic has internal ground fault protection (GFP) built-in. Since 2008, the NEC requires a DC-
GFP on all PV systems in the USA. The built-in DC-GFP eliminates the need to purchase and install
an external DC-GFP. If the internal grounding jumper is installed in a Classic, the battery negative
and DC source negative must not be connected to the system grounding conductor anywhere in the
system. Grounding of these circuits will defeat the GFP function. In a network with multiple Classics
connected in Follow-Me, only one Classic should have its internal grounding jumper installed and all
should have GFP enabled. The factory setting will make a DC negative-to-system ground connection
in the Classic. Disabled the GFP function for positive ground or an ungrounded DC system.
The ground fault device is simple to understand and use. It
detects a fault between battery/PV negative and earth ground
just like the breaker DC-GFP system. The difference with the
Classic is that it turns off the charge ability and sounds a loud
warning when a ground fault is detected. The Classic’s system
consists of a PTC that is between the negative and ground
internally in the Classic. A PTC is a self-healing fuse that will
open when current exceeds its rating and reclose when
current is dropped below its rating. The Classic will monitor
Figure 10 – Chassis Ground Point
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