For example, one common wire size used in the NEC has a cross-section of 250,000 circular mils, written as 250 kcmil or 250 MCM, which is the first size larger than 0000 AWG used within the NEC. 1000 circular mil equals 0.5067 mm2, so for many purposes, a ratio of 2 MCM ≈ 1 mm2 can be used with negligible (1.3%) error.
Copper wiring has a high tensile strength to protect against breakage as well as other forms of physical damage. Copper wiring also has a lower thermal expansion coefficient than its aluminum counterpart. In other words, it doesn't expand as much as aluminum wiring when exposed to heat.Jan 3, 2020
Which is better wire copper or Aluminium?
It's often preferred, in fact, over aluminum wiring because of its high tensile strength. The tensile strength of copper is roughly 40% higher than that of aluminum. With a higher tensile strength, copper wiring is less likely to break than aluminum wiring.Jan 3, 2020
Should I use copper or aluminum entrance cable?
In addition to a lower price tag, aluminum wiring is somewhat easier to work with an copper wiring. Copper wiring is stronger, so it's less likely to break. Aluminum wiring, however, is more flexible, making it easy to work with in small spaces.Jan 3, 2020
Why is aluminum wire used for service entrance?
Aluminum provides a better conductivity to weight ratio than copper, and therefore is also used for wiring power grids, including overhead power transmission lines and local power distribution lines, as well as for power wiring of some airplanes. ... It has cost and weight advantages over copper wires.
What type of wire is used for service entrance?
SE-U is most commonly used for service entrance applications, to connect the meter socket to the main breaker panel. It is also commonly used for overhead service drop applications, to connect the overhead service cable to the meter socket.