[Code of Federal Regulations]
[Title 30, Volume 1]
[Revised as of July 1, 2006]
From the U.S. Government Printing Office via GPO Access
[CITE: 30CFR77]

[Page 648]
 
                       TITLE 30--MINERAL RESOURCES
 
  CHAPTER I--MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR
 
PART 77_MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK 
AREAS OF UNDERGROUND COAL MINES--Table of Contents
 
     Subpart J_Low- and Medium-Voltage Alternating Current Circuits
 
Sec.  77.900  Low- and medium-voltage circuits serving portable or 
mobile three-phase alternating current equipment; circuit breakers.


    Low- and medium-voltage circuits supplying power to portable or 
mobile three-phase alternating current equipment shall be protected by 
suitable circuit breakers of adequate interrupting capacity which are 
properly tested and maintained and equipped with devices to provide 
protection against undervoltage, grounded phase, short circuit, and 
over-current.