Can de-ionised (DI) water conduct DC electricity when solar panel cleaning?  This is an excellent question.  In this article, we will break the question down and discuss a few things.  Firstly, what is DI water?  Secondly, what is DC electricity?  Thirdly, what happens when you mix DI water and DC electricity when solar panel cleaning?

What Is DI Water?

De-ionised water is water that is demineralised.  It is water that has most of the ions removed.  Ions are present in tap water everywhere as they are picked up from the pipes, the natural environment or from other sources.  Usually, these include Calcium, Sodium, Copper and Iron.  The de-ionisation process removes these mineral ions.  In the case of solar panel cleaning, this is done with a DI or reverse osmosis (RO) system.

DI systems vary in nature and structure and different areas require different stages of de-ionisation purification due to the local water hardness and other factors.  The main principle of all of them though, is to remove ions from water and make it ‘pure’ or de-ionised.

When the water is de-ionised, it is used in a variety of applications.  It is often used in chemistry and laboratory applications, industrial processes, cooling applications, boiler feed, aquariums and in the automotive industry.  In our application, it is used for solar panel cleaning.  Why?

Why Use DI Water For Solar Panel Cleaning?

Put simply, DI water has great capacity to absorb ions, dirt, dust and other particles. Water’s natural propensity is to accumulate dirt. So the purer the water, the more quickly it will accumulate ions and dirt. This is important for solar panel cleaners to know. DI water provides an excellent quality of cleaning on solar panels because it removes a greater amount of dirt quicker and leaves a spot-free finish. There are no mineral deposits left on the solar panels, reducing hotspots.

What Is DC Electricity?

Direct Current (DC) electricity is a one-directional flow of charge. The electricity flows in a constant direction, making it different from alternating current (AC). DC has many uses including charging batteries, smelting aluminium and other electrochemical processes. It is also used on railways and to transmit large amounts of power from remote power generators.

It is important for solar panel cleaners to know that solar panels create DC electricity. Electrocution from DC electricity is a solar panel cleaner’s biggest risk. The most likely entry points are the hands and feet. Below is a photo showing a mmild injury from a DC shock. Injuries and burns can be A LOT worse, resulting in losses of limbs or death.

Does Water Conduct Electricity?

No.  Water does not conduct electricity.  This is a common misconception.  It is not water itself that is the conductor for electricity, it is the ions within the water that conduct the electricity.  This is the reason that DI water does not conduct electricity.  There are no ions present, so electricity does not flow through the water.  However, ionised water, water with mineral content, does conduct electricity as there are ions for the electricity to travel through.

When Will My DI Water Conduct Electricity?

It is important to repeat two important points that we have stated:

  1. De-ionised water does not conduct electricity.
  2. De-ionised water has a great propensity for collecting dust, dirt and ions.

Therefore, at the point where your DI water leaves your filtration system, you could hypothetically spray it onto a live DC circuit, such as an open solar panel.  But we do not recommend it, even then!

Your DI water may pick up mineral impurities from your water tank, hosepipes and brush.  If it does, it is no longer de-ionised.  It has picked up ions along its journey from filtration system to solar panel.  If you have had your solar panel cleaning setup running for some time, your DI water may have flushed all impurities out of your kit.  You may test your water fresh out of the brush head or hose and the Total Dissolved Solids (TDS) meter reading may be zero.  At that point, your water is still de-ionised and it cannot conduct electricity.

However, the moment your water picks up ions, it will conduct electricity again.

Can DI Water Conduct Electricity When Solar Panel Cleaning?

It is technical, but we must be exact.  Pure DI Water cannot conduct electricity.  However, as soon as you place your brush on the solar panel and your pure DI water comes into contact with dust, dirt and ions sitting on the solar panel, it will become conductive.  It will start to conduct electricity.  So the moment your brush hits the glass of the panel, electrocution is a possibility.  This is an instantaneous process.

Remember how we said that DC electricity has a constant, one-way flow?  Well, if your water-fed pole is made from carbon fibre, you should understand it is a good conductor of electricity.  If DC electricity comes into contact with ionised water via your conductive water-fed pole, you will receive a constant electric shock.  The effect of DC electric shock on the body is discussed in another article. It is important to understand that the effects of a DC electric shock are severe.

This guy for instance, is not only at risk of a fall on a wet roof, but is also at risk of DC electrocution.

man cleaning solar panels unsafely on a roof

So our original question was ‘Can DI water conduct electricity when solar panel cleaning?’  The answer is that DI water can never conduct electricity.  However, the moment that you start using DI water to clean a solar panel, it becomes ionised and the risk of electrocution become immediately present.

It is for this reason that one of the subjects covered in ISCA safety awareness courses is DC electricity.  The safety awareness courses answer the following questions:

  1. Where are the main points of electrocution on a solar array?
  2. What faults should you be looking for to protect yourself from electrocution whilst solar panel cleaning?
  3. What steps can you take to protect yourself from electrocution whilst solar panel cleaning?

After completing an ISCA course, you are issued with certification.  This proves to solar array owners that you have awareness of the equipment that you are working on.  It shows you have paid attention to your health and safety, the health and safety of your employees and removed the solar array owner of any liability, should an accident occur to you.

ISCA trainings provide peace of mind for you, your family, your employees and your clients.  They set you apart as a solar panel cleaning professional.