Solar Array - Grounding

Do solar arrays (the frames) need grounding? The inverters in most cases are DC (and isolated from mains) and indeed micro-inverters are class 2 with isolated DC inputs from the array. 

Being d.c. alone doesn't solve the shock risk issue - as even modest arrays can run a several hundred volts - which demands proper protection from shock (as per chapter 41).  A lot of modern inverters (i.e. transformerless designs) don't necessarily reliably isolate the d.c. side from the mains/earth either. Some small systems might run as SELV/PELV on the d.c. side.

The usual solution (as recommended by the updated section 712) is to use double/reinforced insulation as the method of protection against electric shock on the d.c. side (both for wiring systems and other equipment) - with the inverter away from the panels (or class II micro inverters and double insulated a.c. wiring system in the vicinity of the panels) that then usually removes any need to Earth any part of the panels for normal shock protection reasons.

On very large systems you might well have problems of static (or capacitive coupling with a.c. parts of the system) building up a charge on the metalwork so would want to earth them. But then it's just a matter of picking a suitable earthing system as you would for anything else in a similar situation (e.g. probably not PME if it's outdoors and/or easily touched by those in good contact with true Earth).

   - Andy.

Do solar arrays (the frames) need grounding? The inverters in most cases are DC (and isolated from mains) and indeed micro-inverters are class 2 with isolated DC inputs from the array. 

Being d.c. alone doesn't solve the shock risk issue - as even modest arrays can run a several hundred volts - which demands proper protection from shock (as per chapter 41).  A lot of modern inverters (i.e. transformerless designs) don't necessarily reliably isolate the d.c. side from the mains/earth either. Some small systems might run as SELV/PELV on the d.c. side.

The usual solution (as recommended by the updated section 712) is to use double/reinforced insulation as the method of protection against electric shock on the d.c. side (both for wiring systems and other equipment) - with the inverter away from the panels (or class II micro inverters and double insulated a.c. wiring system in the vicinity of the panels) that then usually removes any need to Earth any part of the panels for normal shock protection reasons.

On very large systems you might well have problems of static (or capacitive coupling with a.c. parts of the system) building up a charge on the metalwork so would want to earth them. But then it's just a matter of picking a suitable earthing system as you would for anything else in a similar situation (e.g. probably not PME if it's outdoors and/or easily touched by those in good contact with true Earth).

   - Andy.