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ISSUE DATE: April 13, 2016
LAST VALIDATED: 03/31/2021



Administrator for
Coal Mine Safety and Health


Reissue of P10-02 Examination of Electrical Underground Coal Mine Equipment

Who needs this information?
Operators of underground coal mines, miners’ representatives, Mine Safety and Health Administration (MSHA) enforcement personnel, and other interested parties should have this information.

What is the purpose of this bulletin?
This Program Information Bulletin (PIB) is a reissuance of PIB No. P10-02. It provides information to the mining community on examination of electrical underground coal mine equipment, under 30 C.F.R. §§ 75. 512, 75.800-3, 75.821, and 75.900-3, regarding equipment that is put into service for the first time, out-of-service equipment, and idled equipment. In addition, this PIB provides information for consistent enforcement of 30 C.F.R. §§ 75.512, 75.800-3, 75.821, and 75.900-3.

Electrical Equipment Put Into Service For The First Time.
To ensure that electrical equipment put in service for the first time in an underground mine is properly installed to prevent fire, electrical shock, or operational hazards, it should be examined before use. In addition, the equipment must be examined at least weekly under 30 C.F.R. § 75.512-2, at least once every 7 days under 30 C.F.R. § 75.821, and/or monthly in accordance with 30 C.F.R. §§ 75.800-3 and 75.900-3.

Out-of-Service Equipment.
Equipment may be out of service due to scheduled vacation time at a mine, for maintenance or repair, or for any reason other than being idled as discussed below.  Out-of-service equipment should be de-energized.  De-energization can be achieved in a number of ways: removing power from the equipment by disconnecting circuit breakers or cable couplers; disconnecting the cable from the power center and rolling up the cable to the equipment; or other methods dependent on the system.  To ensure that equipment remains de-energized, it should be locked out and tagged at the equipment or the power center.  When equipment is out-of-service, it should be labeled with a tag to identify it as “out of service.” Locking out and tagging equipment alone does not indicate that the equipment is out of service unless the tag actually says that it is out of service, since there are other reasons equipment may be locked out and tagged.

Out-of-service equipment should be listed as “out-of-service” in the electrical examination records, either in the weekly examination record or in the monthly examination record for circuit-breakers, whichever applies.  Defective circuit breakers and receptacles cannot always be locked out.  In these instances they can be de-energized by removing the conductors from the line or load side of the circuit breaker and/or removing the conductors supplying the receptacle, and suitably tagging the defective circuit breaker or receptacle to indicate how the circuit breaker or receptacle was removed from service.  Before such equipment is returned to service, it must be examined, in accordance with 30 C.F.R. §§ 75.512, 75.800-3, or 75.900-3, if the equipment was out of service for a period of time exceeding the examination frequencies prescribed by these standards. 

Idled Electrical Equipment.
Idled electrical equipment is equipment that is not in use, but is ready to be used at any time when the need arises.  Idled equipment should be maintained in a safe operating condition so that it can be used safely when needed.  This equipment must be examined weekly, in accordance with 30 C.F.R. § 75.512-2, at least every 7 days in accordance with 30 C.F.R. § 75.821, or monthly, in accordance with 30 C.F.R. §§ 75.800-3 or 75.900-3.

What is the background for this PIB?
Several accidents have occurred where miners have been shocked by electrical equipment that had not been examined prior to being placed in service. 

In addition, questions have been raised regarding what constitutes out-of-service equipment, how enforcement personnel determine whether equipment is out of service, and how enforcement personnel apply 30 C.F.R.  §§ 75.512, 75.800-3, 75.821 and 75.900-3 to such equipment.

What is MSHA’s authority for this PIB?
The Federal Mine Safety and Health Act of 1977, as amended, 30 U.S.C. § 801 et seq.; 30 C.F.R. §§ 75.512, 75.800-3, 75.821 and 75.900-3.

Is this PIB on the Internet?
This PIB may be viewed on the Internet by accessing the MSHA home page ( ) then choosing “Regulations”, then “Policy and Procedures”, and “Program Information Bulletins.”

Who is the MSHA contact person for this PIB?
Mine Safety and Health Enforcement, Division of Safety
Rodney Adamson, (202) 693-9549

Who will receive this PIB?
MSHA Program Policy Manual Holders
Underground Coal Mine Operators
Coal Special Interest Groups