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A GCM or ground continuity monitor (also called a ground integrity monitor or ground continuity tester) is an electrical safety device that monitors the impedance to ground of a temporary electrical circuit and can provide indication (or protective trip) in the event impedance rises to an unsafe value. A GCM is either an external testing device or a cord mounted device that measures the electrical continuity of a circuit’s path to ground. == Regulatory == Ground continuity monitors are a means to provide protection to workers as part of OSHA regulations.〔Safety and Health Regulations for Construction, Wiring design and protection. 29 C.F.R § 1926.404 (1996) https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=10705.〕 This OSHA regulation applies only to construction sites. (e.g. early stages of construction where access to a reliable ground might not exist or where portable generators might be used) The use of ground continuity monitors is one option in these environments. GFCI protected circuits are also one option under the OSHA standard. Specifically, the OSHA regulation specifies “The employer shall use either ground fault circuit interrupters … or an assured equipment grounding conductor program … to protect employees on construction sites.” 〔Safety and Health Regulations for Construction, Wiring design and protection. 29 C.F.R § 1926.404(b)(1)(i) (1996). https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=10705〕 The OSHA regulation also requires that each ground conductor and/or cordset shall be inspected each day, prior to use and after maintenance. The ground is required to be checked for electrical continuity and this test must be documented. The automatic cord mounted GCMs eliminate the need to test each cord or circuit, since the electrical impedance to ground is measured at the attached cord device and visibility indicated there via an LED. These inspections are required by the OSHA regulation on “receptacles which are not a part of the permanent wiring of the building”.〔Safety and Health Regulations for Construction, Wiring design and protection. 29 C.F.R § 1926.404(b)(1)(iii)(D) (1996). https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=10705〕 As discussed earlier, the permanent wiring of a building might not be established during the early stages of a construction site and therefore would necessitate some assurance of ground protection. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Ground continuity monitor」の詳細全文を読む スポンサード リンク
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