Earthing panels?

Seaplane · Jul 22, 2011

My installation has recently been completed and it was noted that there was a slight voltage on the panels themselves and associated roof framework. (One of the installers nticed a very slight tingle when he touched the metalwork of the panels and the scaffold.) The voltage was measured at 70VAC. The meter on DC showed zero! On the advice of the inverter manufacturer, the inverter was replaced however, this failed to cure the fault.

After much discussion with the manufacturer, the installers were advised to earth the panels and framework to the consumer unit earth point. This was done and the voltage on the panels fell to zero.

Has anyone heard of this before? Any thoughts?

Jon

Graeme Harrold · Jul 22, 2011

What earthing system is the property on?

Was the inverter transformerless?

Seaplane · Jul 22, 2011

Sorry, not sure about earthing system. House is 16 years old and earth from consumer unit seems to be connected directly to earth in the supply box.

Yes, the inverter is transformerless.

lamb · Jul 22, 2011

Capacitive charge in relation to earth due to a transformerless inverter having limited separation between D/C circuit and the earthed neutral of the A/C low voltage grid.

Graeme Harrold · Jul 22, 2011

Array should have been earthed anyway, should have followed the guidelines in the Dti Guide.....see page 22/23. You also need to brush up on earthing systems to know when to rod or not.

Seaplane · Jul 22, 2011

Thank you to Graeme and Lamb for your help. Much appreciated. :smiley2:

Pwee · Jul 23, 2011

Graeme Harrold said:
Array should have been earthed anyway, should have followed the guidelines in the Dti Guide.....see page 22/23. You also need to brush up on earthing systems to know when to rod or not.

My course went to great lengths to say that the array is outside the equipotential zone and doesn't need earthing. It makes you wonder if all these training provides are singing from the same MCS approval song sheet?

Another training centre that I did my WAH course was saying "oh yes, you can fit panels right up to the edge of a roof!" I pity the poor sods who follow that advice and get the MCS assessor round.