Solar Lattice

Mitigation

DC wiring check

ID
mit:dc-wiring-check
IRI
https://solarlattice.org/kb/mit/dc-wiring-check
Status
active
Also known as
Conductor Connections check, Check the Electrical Connection, Polarity check

A DC wiring check confirms that each DC conductor sits on the correct terminal and is labeled. It also checks DC input polarity, with the DC switch off, and makes sure cable routing leaves no sharp edges pressing on the insulation. When the inverter reports a reverse PV input connection, turn the DC switch off and open the fuse holders to isolate the strings. Then use a meter to find the string wired with reversed polarity and correct its connection. When the inverter reports high dynamic leakage current, disconnect it from the grid, isolate the strings and test them with a meter. Then reconnect one string at a time and restart the inverter until the alarm returns. Trace that string to find where it leaks to earth ground. During installation, check the polarity of the DC input conductors with a multimeter to avoid reverse polarity. Confirm both polarity and voltage before you install the fuses. As routine maintenance, one manual calls for checking all cable connections every 6 months. Open the DC and AC disconnects, lock out all sources and confirm that no voltage is present. Then look for loose cables and for cable surface damage. Industry O&M guidelines list inspection of DC and AC cable integrity and cable terminals as a minimum yearly task. A check alone does not fix damaged cable. Damaged runs need replacing or repairing, with routing and strain relief corrected, and insulation integrity should be confirmed after the repair.

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