Lightning during heaving thunderstorms can destroy sensitive electronic gadgets even when there is no electricity at that moment. Lightning strikes at power lines can send a surge of electricity down the wires and into your household appliances. Appliances that run on 220-volt alternating current can handle momentary voltage surges up to 279 volts, but surges beyond that point will cause severe damages to those electronic gadgets. Lightning-induced surges can spike to several hundred volts. You can help protect your devices from lightning strikes by using surge protectors. However, in severe storms, the best protection is to unplug your appliances and disconnect inverters, computers, and cable lines.
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The only danger during thundering storms and lightening is the passing of surge voltages (momentarily high voltage shots from lightning) through the TV antennas, Cable discs or any electrical wiring on the rooftops in the house. These are the ideal carriers of the surge voltages to down the house through the wiring and can damage anything or any electrical or electronic appliance coming in their way. In the homes, equipped with electrical earth conductors on the rooftop connected to the ground generally, this surge voltage will pass on to the Earth without doing any damage to the other things. Many times these electrical conductors are not properly grounded and do not work for the intended purposes.
These surge voltages are of high magnitude, but their duration is small, and that is the reason that many times they do not damage much as they subdue very quickly.
From electricity flow principles, there should not be any appliance connected to the electrical lines during that time and also any other backup like generator or Inverter should also be turned off and not to be used. However, in an instance where you have set up solar panels on your rooftop, there is no way to escape this damage because the bolts of lightning will hit the panels that will immediately transfer current directly to your indoor inverter thereby causing sensitive damages to it (as in the case of my Luminous EcoVolt inverter).
The most common source of lightning-related damage is not the direct strike but voltages and currents induced as a result of the strike.
These tend to divide up into two general categories:
- Damage caused by voltage gradients produced the flow of lightning current through the earth. This can cause ground rods at opposite sides of the building to be at different potentials. Proper earth ground and Equipment Grounding Conductor layout can mitigate this. Connecting the frames of your panels directly to their own ground electrode can make this far worse.
- Damage caused by voltages induced directly into the AC and DC wiring systems by the electric and magnetic fields produced by the lightning. These tend to be able to provide large but limited currents and so Surge Protective Devices (SPDs) in the right places can help mitigate the damage. A quick rule of thumb for the AC side is a large SPD at the main panel and additional smaller ones as close as possible to sensitive equipment. You can also reduce induced voltages by keeping all of the wires for a particular circuit close to each other and if possible twisted, and by putting wiring into shielding raceways such as properly grounded conduit.
My inverter was a victim of this; this morning, at around past 4 o'clock I was awakened in the middle of a thunderstorm by an almighty BANG from the front of the house, and the room went dark. Not so great since my solar system was supposed to prevent that from happening! I got up and headed for the inverter room - and noticed that the inverter led light that was supposed to show GREEN that signifies ON or ORANGE color that signifies OFF on the inverter was showing nothing; only the inverter fan kept working non-stop till morning. In the room there is no smell of cooked electronics, the charge controller is still working, and the batteries were getting charged from the little sunlight out there.
Surge protectors can’t help you in most cases because it protects the voltage difference after a Brownout occurs and lightning works differently.
Just after thinking of the amount to spend on the inverter to fix this damage, I came up with a GREAT and simple solution. There is no need to screw open the inverter or to change your batteries; in fact, no need to spend a dime.
What is this solution? I took a plier instead of a spanner to carefully unscrew the nut that holds the black negative (-) cables to the battery so as to avoid shock and then reconnected it back to its position; this reboot/reset the inverter by blinking all lights while making an uninterrupted beep sound for like 3-5 seconds and then power is restored in the house. Also, no other devices in the house and on the same circuit as the switch were damaged.)
This simple solution has saved me a few bucks to drink Pepsi for some months.
Why just inverter? Don't forget that any equipment in your home is equally vulnerable to lightning. Any other equipment, which could even be costlier than an inverter, also can get damaged, so turn off all your appliances when it's raining.
Sometimes it is good to manually shutdown and restart your solar inverter, or reboot, as it may be called. You may want to do this if you have an error message on your inverter, or just to check that all the switches are on, as sometimes they will go off for no apparent reason.
Hopefully, you have a user manual from the company that supplied your inverter, but if you don’t just follow these steps.
Step 1 – AC off
Switch off the AC isolator. You will always have one in your switchboard, or meter box, and you may also have one by your inverter. This could be labeled up as ‘AC switch’ or ‘Solar Supply Main Switch.’
Step 2 – DC off
Switch off the DC isolator which should be located underneath the inverter.
The screen should go blank, and the lights should go off. Leave it like this for 5 minutes or so, and then switch back on.
Step 3 – DC on
It is very important that you restart by switching the DC isolator on first, as you shouldn’t switch DC under load (ie with the AC on), as the isolator could arc.
Step 4 – AC on
Put the AC switch (solar supply main switch) back on, and then wait. All inverters take at least one minute to restart, and you may see the lights flashing while the inverter does internal testing. There will also be a variety of messages on the screen again as it tests. This is quite normal.
Knowledge is power.