The April 2005 edition of NEC Digest contains a ground-breaking article entitled “Handholes and Underground Electrical Enclosures”. This educational article presents a thorough understanding of issues relating to the performance of underground enclosures and explains the importance of safety standards, including the 2011 NEC, ANSI/SCTE 77-2010, and UL listing.
The 2011 edition of the National Electric Code addresses underground enclosures. The NEC now states in article 314.30 that enclosures “shall be designed and installed to withstand all loads likely to be imposed,” and addresses issues related to enclosure size, wiring entries, enclosures without bottoms, and bonding requirements for covers.
The Code references the ANSI/SCTE 77-2010 “Specification for Underground Enclosure Integrity” National Standard 2, which outlines various tests that enclosures must pass to meet the standard. ANSI/SCTE 77-2010 also provides load charts with Tier ratings to help end users determine the appropriate enclosures to select depending on the loadings expected in the application.
All QUAZITE® enclosures meet or exceed the test provisions of ANSI/SCTE 77-2010 and most Polymer Concrete enclosures sized 30” x 48” and smaller are even UL Listed to the ANSI National Standard as referenced in the 2011 NEC. This means that QUAZITE® enclosures have undergone rigorous physical, environmental and internal equipment protection tests and have been found by UL, a neutral third party, to meet the test requirements of the ANSI National Standard.
No one wants to be responsible for an accidental electrocution from a collapsed enclosure or energized cover. By using the 2011 NEC, ANSI/SCTE 77-2010 and UL Listing requirements in the enclosure selection process, end-users will help ensure long service life, increase safety and reduce potential liability associated with failed underground enclosures.
Underground enclosures must successfully pass numerous material and product performance tests before they can meet ANSI/SCTE 77-2010. These tests include:
NOTE: Quazite recommends testing by third party organizations such as UL to verify that enclosures meet all test provisions of ANSI/SCTE 77-2010.