SMA SB 3000-US - Manual (Page 85)

SMA America, LLC 11 Cleaning and Care
Installation Manual SB30-40-US-IA-en-34 85
11.6 Checking the PV Plant for a ground-fault
If the red and yellow LEDs glow, there may be a ground-fault in the PV plant.
Check each string of the PV plant for a ground-fault as per the following procedure:
1. Open the DC Disconnect (see Section 9.3).
2. Measure the voltages at all PV strings:
• Measure the voltages between the positive terminal and the PV protective conductor.
• Measure the voltages between the negative terminal and the PV protective conductor.
If there is a voltage between the negative terminal of a string and the PV protective conductor
or positive terminal of a string and the PV protective conductor, there is a ground-fault in the
string.
• The approximate position of the ground-fault can be determined from the ratio of the
measured voltages between the positive terminal against the PV protective conductor and
the negative terminal against the PV protective conductor.
• Eliminate the ground-fault.
If there is no ground-fault and the message continues to be displayed, contact the
SMA Service Line.
Danger to life due to electric shock
Death or serious injuries due to high voltages at the PV array.
• Only touch the insulation of the PV array cables.
• Do not connect strings with ground-faults to the inverter.
Risk of electric shock
Normally grounded conductors may be ungrounded and energized when a ground-fault is
indicated by the inverter.
• Check the PV-system for a ground fault and replace the ground fuse as described in this
document.
Destruction of the measuring device due to excessive voltages
• Only use measuring devices with a DC input voltage range of at least 600 V.