Ungrounded arrays can be just as safe—or safer—than grounded
arrays. If installed correctly, with proper equipment grounding,
ungrounded arrays may provide the safest installation possible:
The ungrounded system inverters include an enhanced ability to
detect ground faults, and there is reduced possibility of shock
to personnel installing or servicing the system. Without a
connection to ground on the DC side, the largest shock potential
is directly from positive to negative, with very little shock
potential from either ungrounded conductor to ground (or
anything bonded to ground, such as a metallic enclosure). To
understand why this is beneficial, imagine an installer working
on a roof with a negative-grounded system, positioning an
energized, positive PV source circuit home run in a metal
junction box. If the installer’s hand grazes against the metal
box, the box completes the circuit between the positive and
negative, which creates a serious shock hazard. (Safe working
procedures should prevent this, but th