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NOVEMBER 2, 2022

Trenching for EV charger installation

In some situations, the best option for wiring your EV charger installation is to go underground - this is where trenching comes into play! 

Even if a trench is required, not all electricians will include digging in their estimate. It may end up as your responsibility to coordinate and schedule the digging of the trench. If you find yourself in this situation, contacting a landscaping contractor is your best bet for this type of work.

When sourcing a "trenching" contractor for your EV charger installation, there are a few things to keep in mind. 

  • Usually, 18 "full inches" of fill are needed to cover the conduit, meaning contractors must dig a minimum 20-inch deep trench.

Aside from depth, the length of the trench is also essential. This is calculated by measuring from two points:

  • Where the wiring exits the building/electrical connection.
  • The remote location of the charger.

Common issues when digging a trench can arise from anything: a nearby tree's root system (the larger the tree, the bigger the roots), sprinkler lines, and drainage lines. Your neighborhood utilities like water, gas, and electricity may also cause an issue - however, these are all typically easy to spot.

A good rule of thumb is that anyone living in densely populated urban areas will likely run into digging issues and have to take extra precautions beforehand. If burial depth is a problem, 4" of concrete over the top of the conduit will suffice and meet code requirements.

Other things to consider:

  • Would the wiring path need to go under a driveway or sidewalk? This will most likely require a site visit before the commencement of work.
  • Are there other features of your property that may interfere?
  • Features might include large plants, rockeries, paving stones, rose gardens, irrigation, septic systems, and drainage systems that won't allow for easy digging with a shovel.
  • How will the charger be mounted:
  • On a sturdy fence post? A new post installed with an adequate foundation? A landscape contractor is also a good point of contact for any post-installation questions. 

Many trenching installations require a site visit and coordination between the electrician and the persons providing the digging services. Unless otherwise specified, customers should assume that they will be responsible for facilitating any coordination. In some scenarios, your electrician will take care of the needed steps for trenching - we recommend discussing this beforehand to avoid any confusion.

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