Solar Array - Grounding

vantech said:

Do solar arrays (the frames) need grounding?

The answer is "it depends".

Guidance on this is changing in the 2nd Edition of the IET Code of Practice for Grid-Connected Solar PV Systems, which is due to publish on 29 November 2022. The former 1st Edition (2015) said to earth the frames in most cases, but as others have pointed out, there are pro's and con's:

• in some cases, you earth the frames, to create a touch-voltage say to the satellite disk or terrestrial TV antenna (which can also give a mains-type "ripple" as Mike describes, or if installed properly to the relevant standards, earthed in its own right).
• In other cases, if you don't earth the frames, there is a definite shock risk.

Highlights the fact that protective conductors are not always "safe to touch" (the larger the installation, and the further a cable runs through that installation without further bonding of the protective conductor, or armour or screen, the risk could well increase).

Working practices for roof-mounted systems should perhaps assume that PV array frames are not always "safe to touch", especially from a metallic ladder in contact with Earth. Simply because, even small currents (<1 mA, which could occur through "leakage" even in a double or reinforced insulation DC side), whilst not necessarily highly dangerous in themselves from a shock risk perspective, can cause someone to be startled and fall.

vantech said:

Do solar arrays (the frames) need grounding?

The answer is "it depends".

Guidance on this is changing in the 2nd Edition of the IET Code of Practice for Grid-Connected Solar PV Systems, which is due to publish on 29 November 2022. The former 1st Edition (2015) said to earth the frames in most cases, but as others have pointed out, there are pro's and con's:

• in some cases, you earth the frames, to create a touch-voltage say to the satellite disk or terrestrial TV antenna (which can also give a mains-type "ripple" as Mike describes, or if installed properly to the relevant standards, earthed in its own right).
• In other cases, if you don't earth the frames, there is a definite shock risk.

Highlights the fact that protective conductors are not always "safe to touch" (the larger the installation, and the further a cable runs through that installation without further bonding of the protective conductor, or armour or screen, the risk could well increase).

Working practices for roof-mounted systems should perhaps assume that PV array frames are not always "safe to touch", especially from a metallic ladder in contact with Earth. Simply because, even small currents (<1 mA, which could occur through "leakage" even in a double or reinforced insulation DC side), whilst not necessarily highly dangerous in themselves from a shock risk perspective, can cause someone to be startled and fall.