In Part 6, we started talking about Part III of Article 230 in the NEC. Specifically, we noted that it begins by requiring that the conductor be insulated for the applied voltage [230.30].
New with the 2014 NEC, 230.30 has a Part B. This is a list of wiring methods permitted for underground service conductors. If you look in the Chapter 3 Table of Contents, you will see an Article for each of these wiring methods. It’s nice to have a list right at this point. This is a usability improvement.
Some people believe you’re not allowed to splice service conductors. While it makes sense to splice as little as is practical, you can splice them [230.33]. When you do, you must meet the requirements of 110.14, 300.5, 300.13, and 30015.
Notice we said as little as “practical” and not “possible.” Sometimes, it’s better to have an extra splice. How can this be? Suppose the conductor is running under one of the driveways that feeds your facility’s employee parking lot. If you get to the end of the spool, the splice will end right under that driveway but it will be the only splice needed. If you put a splice on each side of the driveway, you improve accessibility for testing and repair. Consider installing a manhole at each location.
