An educated customer is my favorite customer. Today I will discuss the installation of various types of outdoor wiring. Many residential electrical contractors in N.E. Georgia (Cleveland & Lumpkin) are installing underground wiring in a manner that robs the customer of a quality product in order to make a few extra dollars. Customers need to be aware of the facts. First let’s talk methods.
- Type UF cable. This cable is designed for direct burial. UF cable should not be encased in concrete or exposed to direct sunlight. UF cable is required to be buried 24″Â deep unless it is protected by a GFCI device at which point it can be 12″ deep.
- Type USE (underground service entrance cable). This cable, as well is designed for direct burial. You will see this used for feeding dwellings, out buildings, docks, outdoor pumps, etc. This cable is mostly used for larger loads and long distances. The burial requirements are the same as UF.
- PVC coated low voltage cable. Used for low voltage landscape lighting, not more than 30 volts. minimum depth 6″
- Schedule 40 orÂ 80Â PVC conduit. Designed for direct burial. This conduit is damage, sunlight and water resistant. It is common to install type THWN copper conductors with in this type of conduit. The burial depth of this conduit is 18″ unless GFCI protected in which case 12″ is standard.
- Rigid Metal Conduit or Intermediate Metal Conduit. These conduits are suitable for direct burial only if they are installed with a corrosion resistant material. These types of conduit are rarely seen in a residential settingÂ and are mostly used in areasÂ in which they are subject to heavy damage, corrosive materials, heavy traffic, industrial settings, banks, etc.
In my opinion rigid PVC conduit is the best material to use in residential out door wiring projects. PVC is highly resistant to residential traffic (weed eaters, kids, dogs, etc.) and is quite easily installed. PVC canÂ also be reused. If the conductors inside get damaged orÂ additional circuits are needed it is easy to pull the old out and new back in. Â UF cable on the other hand has seen its problems. It is easily damaged, highly corrosive(ir installed improperly), and rodents love to chew on it. It has a certain protien in the outer jacket that rodents love. I would not recommend its useÂ for more than 10 foot runs. Some electrical contractors prefer to use UF cable because of the ease of use and cost if install. It is true that it is cheaper to use UF cable initially and it is more expensive to install PVC initially. However the end result with PVC is a far better, more versatile, longer lasting product that has a very low failure rate.