Standard value of grounding resistance of solar container station

The NFPA and IEEE recommend a ground resistance value of 5 ohms or less while the NEC has stated to “Make sure that system impedance to ground is less than 5 ohms specified in NEC 50.56. In facilities with sensitive equipment it should be 5ohms or less”. [pdf]

Insulation resistance requirements for solar container systems

To pass International Electrotechnical Commission (IEC) standards for insulation resistance testing, PV systems with an open circuit voltage rating greater than 120 Vdc must have an insulation resistance greater than 1 MΩ. [pdf]