The national electric code is 6″ deep for low voltage wire. I am amazed how often this is not followed. I recently visited a competitor’s website who also works in Northern Virginia and the web site stated that they bury their wires between 2-12″. I am sure that given the choice to bury wire 2″ versus 12″, the 2″ depth is going to be chosen more often, because less work is involved.
It is rare to find someone willing to bury the wire the proper depth per code. Most of the time this is the last thing people think to ask about on their design consultation when interviewing outdoor lighting companies. Read this post on the benefits of hiring an outdoor lighting specialist versus a regular landscaper who does not specialize in lighting, and what you should look for when choosing a lighting contractor.
Below are some pictures of a poor landscape lighting wiring job, and pictures of the high quality trench/wiring our company does.
POOR JOB: This was an installation by a landscaper about 2 months ago (Jan. 2009) at an entranceway in Prince William County, VA. The landscaping company did not even bother to bury the low voltage wires under the mulch.
GOOD JOB: This is one of our specially designed trenching tools that we use. Here it is submerged in the ground. My hand marks the place on the handle which in the next picture shows the depth of the trench.
GOOD JOB: Here my hand marks the exact depth that the trenching tool went into the ground to create the trench, approximately 12 inches.
GOOD JOB: This is our open trench, 12 inches deep. Notice the minimal disruption with respect to surrounding landscape/lawn. In the next step, we will bury the wire and close the trench.
4 Comments
March 24, 2009 at 9:01 am
[...] Outdoor Lighting franchise partners from Northern Virginia does a great job blogging. They wrote a post about burying low-voltage wires. This is the subject. The third part, the message, is the relate. [...]
August 8, 2009 at 10:46 pm
Not personalizing this is hard because the advice so overly complicates installation of a 12 v system that its likened to mandating the brushing teeth only with the proper sized bristle in tight little circles one at a time, flossing only parallel to the earth and three times daily. The low voltage system is designed to provide a safer voltage carry and can be disrupted by inadvertent digging without serious harm to pets or humans. There is as much need for the pros and the six inch trenches on a 12 volt installation as there is for a monthly trip to the dentist.
August 13, 2009 at 2:25 pm
Thank you for the comment Sizemoore.
I decided to write another blog post addressing your comment on the burial depth needed for low voltage wiring. It’s obviously a topic where disagreement exists. A quick response is that it is not just our opinion, it is a regulation under the National Electric Code in the United States. My blog post with more information on this is here:
http://outdoorlightsblog.com/2009/08/13/wire-burial-depth-for-landscape-lighting-there-is-actually-a-national-electric-code/
August 13, 2009 at 2:20 pm
[...] – There is actually a National Electric Code! Jump to Comments We recently received a comment on our blog post How Deep Do You Bury Low Voltage Wire? that I thought was worth mentioning in a [...]