Insulation Resistant dropped to 1.7megohms from 20 - help please

[GaryinDevon]

In the last three weeks the insulation resistant reading on the Invertor has dropped from 20 MOhms to 1.7 today. we're in Devon - would there be a leak in the cabling. Can we switch it off. Is it dangerous? Help please
G

 

[SolarCity]

It could be many things. Perhaps a trapped cable which has been made worse by ingress of water.

 

[GaryinDevon]

It could be many things. Perhaps a trapped cable which has been made worse by ingress of water.

I Presume the invertor is measuring the pv array resistance. How do we solve it and is it dangerous - any thoughts on what I can do to halt it. Switching off the invertor presumably wont help. Its still raining here by the way. Could it catch fire? Help please

 

[SolarCity]

The inverter is measuring the PV insulation resistance to earth.

Is it dangerous? Possibly. It sounds like your array is bonded though which reduces the danger. I would say that the biggest issue would be power losses associated with this. The inverter will measure the resistance every morning as it checks grid parameters - if the resistance is too low then it won't power up which will obviously make the losses even worse.

The inverter won't catch fire but this really does need sorting out.

 

[Octopus]

In the last three weeks the insulation resistant reading on the Invertor has dropped from 20 MOhms to 1.7 today. we're in Devon - would there be a leak in the cabling. Can we switch it off. Is it dangerous? Help please
G

How do you know this?

 

[SolarCity]

How do you know this?

Some TL inverter monitor this and show the reading on the display.

 

[Octopus]

Some TL inverter monitor this and show the reading on the display.

Nice. As you can probably tell I don't do solar!

 

[infinity]

Is it a power one inverter? Switch one string at a time off and see which is the low resistance string. Then maybe leave that string off, and call the installer out to rectify the problem. I had this a few weeks back and it was a cable slightly trapped under a panel and when it rained it then caused the low resistance fault.

We removed 2 panels re terminated the cable and reinstated now all is above 20M ohms again.

 

[GaryinDevon]

Some TL inverter monitor this and show the reading on the display.

Yes, it shows on the display and for months has been 20 and has dropped over the last couple of weeks going down in the last couple of days from 7.3

 

[steve Leese]

Is there a loose cable blowing in the wind that has become chaffed and is now liing in the water when it rains, does the resistance go back up when it dries out.

 

[Gavin A]

or someone's not done up the connector tightly enough and you've got water inside the connector.

 

[GaryinDevon]

Well Looking from the garage roof nothing has come undone, if fact it is still generating electricity when the sun comes out. However on one set of eight panels the leads are abovethe roof and on the top set of panels the leads are laying down touching the roof and as you probably saw on the news around Devon we have had an awful lot of rain recently.
I tried to contact My Energy Station, the installers, only to discover that they went into liquidation earlier in the year - so what happens now. None of the phone lines work or mobiles. All suggestions welcome please.
G

 

[SolarCity]

I would say that it is a problem that needs sorting and should therefore be covered under the warranty. As the firm has now gone into liquidation, you should contact REAL and explain to them your problem.

 

[GaryinDevon]

Well, that's very helpful, didn't know about them. Obviously we want to get it sorted asap but meanwhile are worried that it might affect the panels or system.

 

[SolarCity]

I wouldn't worry about the system. The inverter will protect itself and the panels won't be damaged at all.