What to Know About Direct-Burial Underground Cable?

What is a direct-burial cable?

Direct-burial cable is a type of electrical service wire designed for straight placement in underground trench construction without any extra conduit protection. Most of these cables can withstand direct moisture, heat, and soil exposure as they come with waterproofing features that protect them from moisture damage. They also stay protected from damage due to storms or fallen trees. Direct-burial underground cable offers added protection to any electrical system when run inside the conduit.

While standard cables comprise thin insulation layers with an outer waterproof cover, direct-burial wires come with several layers of heavy metallic-banded sheathing, shock-absorbing, waterproofing gel, waterproof tape, and PET tape wrapped around the internal wires, followed by another tape for added shielding.

Direct-burial underground cables have jacketed insulation rated for use in a dry and wet environment, offering it protection from natural elements, facilitating direct burial into the ground. Once installed underground, direct-burial cables are not visible above the ground surface. 

Which underground cables qualify as direct-burial?

For a cable to pass the direct-burial claim, it needs to go through third-party ratings and testing to ensure that it possesses the required mechanical properties for enduring the severities associated with underground and outdoor applications. It has to pass the same stress that a typical conduit withstands. These wires are rated and approved according to the National Electric Code (NEC). People looking to avoid conduits in their electrical installation can use cables with direct-burial ratings.

Direct-burial underground cables are easier and faster to install than other cables. Some industries that commonly use direct-burial cables include oil field construction, gas, communication, power, other utility construction, and projects undertaken by the department of transportation (DOT). In homes, direct-burial cables help extend electrical services to various outdoor applications, like solar panels, landscape lighting, lampposts, detached garages, and sprinkler systems from a particular distribution point.

Types of direct-burial underground cables

For residential projects, electricians use two types of direct-burial cables—underground service entrance (USE) and underground feeder (UF) available with thermoplastic insulations. USE cables are black and often used for electrical services bringing power to the houses through the electric transformer. Only professionals should handle USE cable. 

Underground feeder cables are gray and available in rolls resembling non-metallic sheathed cables. However, unlike standard non-metallic wires, UF’s are meant for use both indoors and outdoors. UF cables are enclosed in a solid plastic sheath to offer protection from external elements. 

Several electrical and building codes govern the direct-burial cable installation for safety reasons. Most local codes require the burial of direct-burial wires at least 18 inches underground. However, check with the electrical inspector for the rules prevailing in the locality. Digging is a difficult task while installing direct-burial cables. Hire a licensed electrician for direct-burial underground cable installation to ensure correct installation after considering local codes governing the area.

A.B.T. Electric is a licensed residential and commercial electrical contractor in Anthem, Az. We are committed to continuing expertise, safety, and customer satisfaction. Call (623) 521-3939 today!