Direct Burial Speaker Wire: Do you need it?
So you have your back yard all landscaped, you have the barbeque installed, the patio furniture is on the way and now you decide it is time to install some outdoor speakers. You realize that the outdoor patio speakers are a piece of cake to wire but now you realize you want to install some rock speakers on the other side of the garden, out by the pool, or out by the new patio furniture in the yard. So now you start to strategize on how you are going to get speaker wire out to the areas you want to place the speakers. So you decide to start looking for some direct burial speaker wire because you have decided just to dig a little trench, put the direct burial speaker wire in the ground, and just bury the wire. The truth is that this installation method in not at all recommended. Your first response to this may be to ask why not? The reality is that burying any wire or cable directly in the dirt is never recommended. Especially if you desire a long lasting installation!
The truth is only a few cables are truly rated to be buried directly into the ground. And for sure direct burial speaker wire is not. Most true underground cables have special jackets along with a special material in the cable such as gel, powder, or water block tape that assists the cable from keeping out moisture while buried. Direct burial speaker wire does not offer any special material internally to protect the internal conductors. Commonly most direct burial rated speaker wire products offer a thicker than average PE rated jacket that give the internal conductors some extra protection against the weather and the sun. But it is still not made to be put directly in the dirt.
The best strategy when installing speaker wire in the ground is to dig a trench and drop some PVC or flexible conduit into the trench for you to later pull your cable through. This will give your direct burial speaker wire a longer installation life. The reality is if you bury the speaker wire right into the ground you will eventually have corrosion which will lead to damaged or non-working cables. The kicker is once the cable is corroded and damaged you will have to re-dig your trench to pull the damaged cable out while having to re-install new wire. If you have a conduit in place and for some reason your direct burial speaker wire has issues it is very easy to simply pull the cable out of the conduit at the same time you pull a new cable. No digging is needed. Not to mention you may realize later you want to install other cable types in those conduits, so it may be smart to leave a pull string in the conduit just in case. You never know about the future with so many new high tech products coming out in the market place. There is a good chance that one day you may want to use that same conduit to install different cable types. So plan for the future!
In the end you can bury direct burial speaker wire in the ground but the question will be how long will it take for it to corrode and have to be replaced. Do you really want to re-dig your back yard up every few years? Or does it make sense to put conduit in those trenches and do it right the first time. Remember direct burial rated does not actually mean just throw the cable in the ground and bury it! We always suggest you use the best installation practices when installing any low voltage cables.