Types, Construction, Applications and Installation of URD Cables
Here’s some basic information you should have on URD
• Underground Residential Distribution cables supply power from transformer to the meter of a structure. They can be used for underground duct application or direct burial. They are available in duplex, triplex, quadruplex, and single conductor options. Each type of URD cable is structured differently than the other and thus performs different functions according to their ratings and construction. On this post, we share answers to some of the commonly asked questions about the different kinds of URD cables.
1. Can the 4/0-4/0-2/0 URD be used from weather head to meter for 200 amp service?
• Yes. The 4/0-4/0-2/0 underground residential distribution cable can be used from the weather head to meter 200 amp service. This is because the cable comes with four conductors. It is stranded, the stranding provides sufficient surface area for transmission of more than 200 amps current.
• There is no ground on the service drop which starts at or after the meter can. Looking at where the wire feeds the house from the pole, you’ll find out that there are two insulated conductors, also called the hots, as well as an uninsulated wire called the neutral. The third cable performs the duty of the neutral and also acts as the physical support for the hots.
• When putting up the meter poles, the weather head needs to be a minimum of18 inches from top of the pole. The meter pole should be trimmed to a minimum of 14.5 feet above the surface of the earth.
2. I was looking at the converse triplex URD 2/0-2/0-1 Is this a great wire to run inside of conduit?
• Yes. It is better that it is installed in a conduit due to possible structural failures which could occur if they were installed by direct burial. A direct burial cable can be run inside a conduit up to 24 inches deep. Since this cable is not a THHN or THWN cable, a PVC conduit is the most ideal setting to install cable. This conduit has a good resistance to corrosion and is easy to install.
• The National Electrical Code (NEC) stipulates that if a conduit only has three or more wires the maximum fill percentage should be 40%. The maximum operating temperature for the converse triplex URD 2/0-2/0-1 should not be more than 90°C in both wet and dry places. The operating voltage should be 600 volts.
3. What size PVC raceway would Notre Dame 1/0-1/0-1/0-2 Quadruplex Aluminium URD Cable be able to pull into for 300 ft run? Is 2 inch PVC schedule 40 the right size to pull into?
• According to NEC, the PVC should give a 40% space allowance in the PVC for fill. When you pool the Notre Dame 1/0-1/0-1/0-2 Quadruplex Aluminium URD Cable through a 2 inch PVC conduit, the space that remains for fill is more than 40% so, yes, it’s the right size.
4. I’m looking at the 2/0-2/0-2/0-1 Syracuse Quadruplex Aluminium Conductor 600V URD 170 feet. What is the minimum conduit size for this cable?
• The minimum conduit size for this cable is 2"schedule 40 PVC conduit.
5. I’m putting in a 100 amp subpanel in pole barn 650 ft house. The electrician says he will need 2 runs of 4/0 aluminum direct burial wire (4 hots) and 1 run of 2/0 direct burial wire for the neutral. Will 4/0-4/0-4/0-2/0 quadruplex aluminum URD cable work?
• Yes. That would be sufficient; 4/0-4/0-4/0-2/0 will work.