Maybe you also have this question: Does wood conduct electricity? The answer to this question can be very important for woodworkers and all those who deal with wood.

Also, if you are looking for useful information in this field or you are a researcher, this article will provide you complete information.  

Electrical Resistance and Conductance of Wood

Dry wood is a good electrical insulator and cannot conduct electricity.

A block of completely dry wood like seasoned wood that uses as firewood is an excellent insulator, which can be compared with insulators such as phenol-formaldehyde resin.

But with increasing moisture, its electrical resistance decreases.

The electrical resistance can be calculated from the following equation:

P=R*A/L  

Where

  • R is the electrical resistance of a uniform specimen
  • L is the length
  • A is the cross-sectional area of the specimen  

Affecting factors in the electrical conductivity of wood

In general, there are many factors in the electrical conductivity of wood. Factors like:

  • Temperature
  • Moisture
  • Wood species
  • Impurity

It can be said that moisture is the most important factor in the electrical resistance of wood.

This is a very important point in the construction of the tool with a wooden handle because they are in constant touch with moisture.

In order to increase the durability and insulation of hand-held electric tools that have a wooden handle, the wood part is saturated with phenol-aldehyde resin to prevent water absorption and increase the electrical insulating property.    

The Relation of Moisture Content and Electrical Conductance of Wood

The relation of moisture Content and electrical conductance of wood

The electrical conductivity of wood increases one million times with increasing moisture from 0 to 30 percent, but with increasing moisture from 30 percent to over (full saturation), the electrical conductivity of wood can be only 50 times higher.

Of course, if the water is pure, it has a lot of electrical resistance and insulation, but due to the presence of solutes in water, conductivity is created in water and the wet wood is similarly conductive.    

The Electrical Resistance of the Wood in Different Directions

The specific electrical resistance of the wood has different values in different directions.

With that said, in parallel to the fibers, it is about half of the direction of the vertical on fibers, and this resistance is in the radial direction equal to or at most 15% less than the tangent direction.

Specific masses and species of wood are less important in their electrical resistance variations.  

Can electricity pass through the wood?


Yes of course. Wood is actually an insulator but it’s not a good one.
At high voltage, it’s easier to get electricity from the inside of wood.
You can learn more about the effects of electricity passing on wood in the fractal wood burning.
If the wood is wet, the equation will change and electricity will be conductive through the wood, even at low voltage.
So be careful when standing up on a wooden ladder while working with electricity.

Why wet wood is a conductor?


The molecules in the wood are spaced apart, so it is difficult to pass the flow of electricity, and it must move from one molecule to another molecule.
If the wood is wet, water molecules fill the gap between the wood molecules and cause the electricity to pass through the wood.    

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