"NEMA Enclosure Types"(PDF). National Electrical Manufacturers Association. November 2005. pp. 7–9. Archived from the original(PDF) on 10 June 2018. Retrieved 10 January 2017.
"NEMA Enclosure Types"(PDF). National Electrical Manufacturers Association. November 2005. pp. 7–9. Archived from the original(PDF) on 10 June 2018. Retrieved 10 January 2017.
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International Electrotechnical Commission (2013). IEC 60529 - Degrees of protection provided by enclosures (IP Code). International standard (2.2 ed.). p. 21. ISBN9782832210864. OCLC864643678.