IEC 62446-1 Summarized

IEC 62446-1 establishes the standard for testing, documenting, and maintaining grid-connected PV systems. We have summarized it below for easy processing and integration into your processes!

IEC 62446 Test	Purpose	Instrument	Challenges for Operative Systems	Recommendation
Grounding System Continuity Test	Ensure that parts of the PV system frame, rack, boxes are grounded.	Ohm-meter or continuity tester	No Problems	Check continuity of ground in any preventative maintenance inspection and before working on system.
Polarity Inspection	To ensure that (+) and (-) wires are not reversed	Volt-meter	No Problems	This test should spot problems upon initial commissioning and not need to be repeated for preventative maintenance inspections- still we do find strings wired in reverse polarity that were not caught in commissioning in which case the string fuse is burned.
Combiner Box Test	Ensures fuses are OK and that current sums as intended.	Digital Multi-meter	Test usually entails shut down of system	While important in commissioning new system, not required for PM inspection as other tests can spot the common problems.
String Open Circuit Voltage (Voc)	Check string is wired correctly inlcuding number of modules.	Volt-meter	Requires shut down of system and removal of fuse from fuse holder to create open circuit can damage aged fuse holders.	Measure operating voltage (Vmp) instead of Voc
String Short Circuit Current (Isc)		test instrument with a short circuit current measurement function (e.g. a specialized PV tester)	Requires "Short Circuit Switch Box" to contain switching arc; requires fuse removal from fuse holder.	Measure operating current (Imp) instead of Isc
Functional Test	Ensure operation of switches, breakers, ground fault, arc fault, other functions.	Not applicable	Requires system shut-down. Aged equipment is likely to fail when exercised.	Some tests, such as inverter shutdown and restart, might be OK, but not recommended to exercise all functions for PM inspection
Insulation Resistance Test	Ensure integrity of insulation on wiring.	Insulation Resistance Tester ("Megger")	Shock hazard; personnel protection; isolation of PV array from ground and from inverter and other equipment. High test voltages may damage devices (eg surge suppressors) or void warranties.	Usually not recommended for PM inspection of operating system- may be employed if wiring problems precipitate a need for it.
IEC 62446 Category II tests
I-V Curve Test	Expose details of current/voltage characteristics	I-V Curve Tracer	Requires system shut-down and same issues as Voc and Isc test.	Not required for PM inspection- Vmp and Imp measurements will expose most problems.
Infrared Scan Test	Identify PV modules or switchgear that is overheating due to improper operation.	Infrared Camera with good resolution	No Problems	Widely recommended in PM inspections. Can be used for PV modules, combiner boxes, connectors, batteries, and AC switchgear
Other Tests
Voltage to Ground-Resistive Ground System	Verify resistance to ground for modules with resistive grounding with manufacturer's recommendation	Loop Impedance Meter	Only for modules with resistive grounding systems. Requires sytem stut down and isolation of modules.	Not generally recommended, but may be required by module manufacturer.
Blocking diode test	Check polarity and voltage drop of diode	Diode Tester	Testing of bybass diodes in PV modules requires opening of junction box (potential leak) and requires module to be covered for measurement of bypass diode or may damage meter.	Not generally recommended, but may be conducted if module performance fails other tests.
Wet insulation test	Identify faults that occur only in wet condition	Insulation Resistance Tester ("Megger")	Time consuming and expensive; inconsistent results.	Not generally recommended
Shade evaluation	Measure shade of surrounding opbjects	Shading Profile Device (eg Solmetric Suneye)	No Problems	Not generally needed, but useful for establishing baseline and monitoring shade growth.
Grid Interface Tests	Check operation of grid-protecting and anti-export features	Special equipment to "inject" voltage and frequency profile into device	Requires sytem shutdown; may require service shut-down.	Not recommended unless required by Grid Operator for typical PM inspection.