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Solar panels need a bit of cleaning every now and then, but how high is the risk of getting electrocuted? These panels generate electricity after all, so is it really safe to clean these modules? Just like with any electrical component, you have to be careful when handling solar current.
Solar cells are covered by glass, but if it breaks and water seeps through, electrocution is a real possibility. Solar panel systems should be turned off before cleaning to reduce the risk, and there should be proper array grounding to prevent lightning induced electric shock.
How Likely is Solar Panel Electrocution?
If the solar panel is installed properly, with fault protection and grounding, the chance of being electrocuted are low. To be safe however, clean the panels during clear weather, and there should be no current passing through the system.
Solar panel systems have built in protection against arcing LNK and electrocution. The glass covering each cell is durable and has sealant around it. Even if the glass gets cracked, you won’t be able to step on the conductive surface unless the seam is significant.
With proper grounding wire sizes LNK, lightning strikes will not lead to electrocution, and fault protection will indicate if there is loose insulation or wiring. Building codes also provide strict rules to minimize electrocution, so if the system was installed properly, the risk will be low.
Solar batteries, inverters and charge controllers also have protection against overloading and overcharging. A charge controller is designed specifically to keep battery charging at a safe level. As current is transmitted from the modules into the battery bank, the controller ensures the battery receives only the proper amount.
inverters have surge protection built in to shield electronics from power spikes, power outages etc. Even portable solar chargers and solar generators have protectors. You probably will not be electrocuted form a single solar cell. The risk is if the wires connecting the system gets shorted or damaged.
And that is the reason why you should not get careless. If you are going to clean solar panels take all the necessary precautions. Any voltage above 10ma produces shock, while 100ma is lethal. Solar panels can reach up to 375V and over 15ma, so you need to be careful. The following tips apply not just for cleaning but also if you want to inspect the modules.
How to Protect Yourself From Solar Panel Electrocution
The best way to protect yourself is to use the right equipment for inspection and cleaning. Your modules should also be inspected by an expert for loose wires on a regular basis. These two steps will go far in ensuring your system runs smoothly and there is minimal risk of electrocution.
Turn Off Solar Panels Before Cleaning
Solar panel systems have two electrical components, AC and DC. The DC is linked to the input while the AC is connected to your house and the grid (if you are on a grid tied system).
To shut down your solar panel:
- Turn off the inverter AC main supply on the meter box. Grid tied systems usually have two AC breakers, one on the critical load and the other on the main panel board. Turn both off.
- Turn off the AC breaker. Your solar panel will no longer supply electricity to the grid.
- Shut off the DC breaker. This is usually in the combiner box. This prevents current from getting to the inverter. Your solar system is completely shut down.
To turn the system back on, repeat the steps above but in reverse. Start by switching on the DC breaker first.
The steps above are for grid tied systems. If you are off the grid, or on the grid but have battery storage, shut down the DC breaker on the battery bank after turning off the combiner box DC breaker.
You have to perform all these steps every time you clean or inspect your solar panels. You should also look up the safety features on the charge controller and inverter for safe shutdown. This will ensure it is safe to work or clean the modules.
The steps above is a general overview. Your solar panel system may have a different configuration. Read the instructions for specific steps on how to shut down your panels.
Install a Rapid Shutdown System
The NEC codes states that a rapid shutdown system should be included in a solar array. This is a precaution in case of fire, allowing the system to be turned off quickly and to safeguard firefighters and emergency personnel.
The NEC code is not a law, so states may or may not choose to follow it. Check the local codes in your area. If it is required, contact an installer to have this feature added to your system. But even if it is not required, having a rapid shutdown system is a good idea. You may have to spend a little extra, but it is worth in case of an emergency.
There are many types of rapid shutdown systems, but basically it consists of a box with an on/off button. This allows you to quickly turn the whole system off in case of electrocution or fire. This is also where firefighters would look to de-energize the PV system. So while the NEC code is not law, it makes sense to have this feature.
Turning off an inverter will not always shut off a solar power system. In some cases, solar cables and wires still retain electricity. This poses a risk not just to firefighters but to anyone who wants to clean or check the solar panels. With a rapid shutdown button you can turn off the power with one switch.
Rapid shutdown systems are designed mainly for fire protection. But you can also use this in case of an emergency. If someone gets electrocuted, you can press the button and turn the PV system off.
Fortunately microinverters and power optimizers today have quick shutdown features. String inverters may require you to install additional components to avail of speedy shutdowns..
Tips For Avoiding Solar Electrocution
While solar panels are generally safe, you should always exercise caution. Follow these guidelines every time you clean your solar modules.
Clean Solar Panels Properly
Clean the modules when the sun is out. Avoid cleaning during the rainy season because the roof is slippery, lightning could strike and strong winds could break the glass. Water could get in the panel and short a circuit or wire. Also, rain does a good job of cleaning solar panels, saving you the task.
Second, use the right tools. For solar panels that means water. You can hose the panels from the ground if possible, or wipe the panels with a mop. Use soapy water for hard to remove dirt. In many cases soapy water isn’t even needed. Water is enough unless there are birds’ nests or other debris scattered around.
Avoid using harsh chemicals because it might stain the glass or worse crack it. If chemicals get on the surface it could render the system inoperable. Left unattended the chemical cold reach wiring and cause an electric shock.
Follow all the safety rules and precautions. The instructions and safety guidelines are there for a reason.. Follow directions for how and when to clean the modules. Doing these will go far in keeping you safe.
Solar panels may need infrequent cleaning , but you should monitor the wires and cables every so often. Your system comes with a performance tracker. If there are dips or sudden changes, it could be due to arcing, blown fuse or other electrical problems.
Use the Right Equipment
If you are going to build your own solar panel or will perform the inspection yourself, be certain you have the appropriate tools.
- Voltmeter. Choose a meter that is suitable for your system voltage. it must be capable of handling the regular voltage and sudden spikes due to arcing. Warless meters are ideal so you can inspect the panels from a distance.
- Test Leads. Buy test leads that are appropriate for your solar panels.
- Protective Gear. Put on safety goggles, gloves, hearing protection and arc rated clothing
- Probes. Accidentally touching metal with metal can short a circuit, so use probes.
- Fuses. Fuses are designed to contain electricity produced by the system. These are critical so always get the best fuses you can buy.
DC and AC Arc Protection
Arc flashes and other electrical hazards can be avoided with AC and DC power protection. AC arc prevention includes switch gear that points arc energy away from you and the system components. DC control measures consists of several string inverters that can combine strings in parallel.
To recap, modern solar panels have built in protection against electrocution, but you can never be too careful. You should only clean the panels when the sky is clear, and always shut the system off first. By taking the right steps you can protect yourself and your system.