Fault finding on Solar PV Panel systems

Why have my solar panels stopped working?!  It’s a frustrating situation, but it can often be quickly and easily resolved.  We’ve put together this guide to help you save time and money.  With a few checks you may be able to get your Solar PV Power station generating again quickly.  Don’t worry if you get stuck, we’re only a phone call or email away if you need us – even if we didn’t install your system.

What do I do if my Solar Panels aren’t working?

To save you waiting for us to get to you and the possibility of a call out fee if the fault is not covered it’s worth going through a few checks of your own first. Here’s what you need to do:

  1. Check your inverter screen. Is there an error message?  If yes, take a photo of it. This will help with the diagnosis and the message may disappear after a time.
  2. If the inverter screen is blank, is it dark outside?  Most inverters won’t liven up unless your solar panels are generating.  If there is enough light outside for the panels to generate and the inverter screen is not showing anything then there’s a good chance there’s no grid supply to the inverter.  
    • Check all MCBs (miniature circuit breakers) and RCDs (Residual Current Detectors) to ensure they’re all in the ON position (up). RCDs may trip to a mid position and may need to be pushed all the way down before they can be pushed in to the up position and stay there. 
    • Check the Total Generation Metre (TGM).  If there’s a solid red LED then there is grid power to the TGM but nothing is being generated. If the TGM’s Red LED is blinking then the system is generating. The rate of the blink is determined by the power the panels are generating. If it’s a really dull day then it may only blink once every 20-30 seconds, so check carefully. If the sun’s out in full then the blinking may occur more than once a second.  If the screen of the TGM is blank and the Red LED is never blinking then it looks like there is no grid power to the TGM.
    • Check your AC & DC Isolators. These are near your inverter and there may also be one near your Consumer Unit (fuseboard) if the Consumer Unit is in a different room to your inverter.  
  3. If all the switches and isolators are on and you’re still not getting any juice from your solar PV then it’s probably time to give us a call.  We’ll help as much as we can over the phone and may ask you to email any photos so we can see if we can get you up and running without having to wait for us to come out and avoid the possible costs of a call out.


There’s grid power to my PV inverter but still no generation.

You’ve confirmed there is a grid connection to the inverter but there’s still no juice.  Here’s some of the more likely issues.

RISO/ISO fault

  • These types of fault are often caused by excess moisture so may only happen on damp/wet days.  It’s quite common for them to clear as the day warms up and dries any moisture out.  If you’ve got monitoring on your system then you may see your system starting to generate later and later in the mornings, especially on damp or wet days.
  • Your inverter is able to detect these faults so will not allow the system to generate until it is cleared.  This will usually be displayed on the inverter screen too.
  • These faults will need an expert to identify and may require investigation.  Give us a call or email and we’ll be happy to help.


MCB/RCD tripping

  • This can happen when the system is starting up in the morning. Sticky relays in the inverter can mean too much current will flow and trip your switches in your consumer unit.  You’ll need to contact us for further investigation.
  • RCD tripping is caused when there is excess leakage current.  RCDs are designed to prevent electrocution and can be very sensitive.  Certain appliances, like PCs, electronic goods and inverters will have a small amount of leakage current in their normal operation.  If several appliances combine on the same RCD then nuisance tripping may occur.  Try turning off different devices to see if you can identify the cause using a process of elimination.  If you still can’t fathom out the cause then give us a call or email.

If your inverter is underperforming or near its sell by date, it might be a good time to consider upgrading to a SolarEdge system. SolarEdge inverters and optimisers have many features which automatically identify problems often before you even know about them. They can also be set up to alert Naked Solar where we can often fix the problem remotely.


Error code - SolarEdge inverter


Consumer Unit MCBs RCDs & Main Switch


Total Generation Meter


DC and AC isolators