Case Studies » Case Study 7: Overhead Crane Servicing and Maintenance

A millwright is assigned to a servicing and maintenance task on an overhead crane. The employee initiates the prescribed energy control procedure by turning "off" the crane's electrical disconnect switch and placing his lock onto this energy isolating device.

However, the disconnect switch lever is corroded, allowing it to physically separate from the disconnect switch assembly. As a result, when the millwright places the lock on the lever in the "off" position, the stub located inside the electrical box remains in the "on" position. The employee does not attempt to verify deenergization by using the crane start button. When he contacts the energized electrical bus bar located near the bridge railings, fatal injury results.

This repairman was trained in the requirements of the Lockout/Tagout standard as an authorized employee. He was not, however, trained as a qualified person under the Electrical-Safety-Related Work Practices standard.

Question 1

Is the employer required to shut down and lock out related machinery operating in the area of the covered service and maintenance, if that machinery could cause injury?

  • Incorrect. In this case, this activity would not be covered.

    The activity that resulted in the electrocution would be covered by 29 CFR 1910.333, the Electrical-Safety-Related Work Practices standard. The Lockout/Tagout standard under, 29 CFR 1910.147(a)(1)(ii)(C), specifies that the Lockout/Tagout standard does not cover exposure to electrical hazards from work on, near, or with conductors or equipment in electric utilization installations.

    29 CFR 1910.333(b)(2) establishes lockout/tagout requirements for work on, near, or with electrical conductors. Among these requirements are specific provisions under 29 CFR 1910.333(b)(2)(iv) to verify that circuits and electrical equipment are deenergized. These provisions include:

    1. (b)(2)(iv) - Verification of deenergized condition. The requirements of this paragraph shall be met before any circuits or equipment can be considered and worked as deenergized.
    2. (b)(2)(iv)(A) - A qualified person shall operate the equipment operating the controls or otherwise verify that the equipment cannot be restarted.
    3. (b)(2)(iv)(B) - A qualified person shall use test equipment to test the circuit elements and electrical parts of equipment to which employees will be exposed and shall verify that the circuit elements and equipment parts are deenergized. The test shall also determine if any energized condition exists as a result of inadvertently induced voltage or unrelated voltage backfeed even though specific parts of the circuit have been deenergized and presumed to be safe. If the circuit to be tested is over 600 volts, nominal, the test equipment shall be checked for proper operation immediately after this test.

  • Correct. The activity would not be covered.

    The activity that resulted in the electrocution would be covered by 29 CFR 1910.333, the Electrical-Safety-Related Work Practices standard. The Lockout/Tagout standard under, 29 CFR 1910.147(a)(1)(ii)(C), specifies that the Lockout/Tagout standard does not cover exposure to electrical hazards from work on, near, or with conductors or equipment in electric utilization installations.

    29 CFR 1910.333(b)(2) establishes lockout/tagout requirements for work on, near, or with electrical conductors. Among these requirements are specific provisions under 29 CFR 1910.333(b)(2)(iv) to verify that circuits and electrical equipment are deenergized. These provisions include:

    1. (b)(2)(iv) - Verification of deenergized condition. The requirements of this paragraph shall be met before any circuits or equipment can be considered and worked as deenergized.
    2. (b)(2)(iv)(A) - A qualified person shall operate the equipment operating the controls or otherwise verify that the equipment cannot be restarted.
    3. (b)(2)(iv)(B) - A qualified person shall use test equipment to test the circuit elements and electrical parts of equipment to which employees will be exposed and shall verify that the circuit elements and equipment parts are deenergized. The test shall also determine if any energized condition exists as a result of inadvertently induced voltage or unrelated voltage backfeed even though specific parts of the circuit have been deenergized and presumed to be safe. If the circuit to be tested is over 600 volts, nominal, the test equipment shall be checked for proper operation immediately after this test.

Question 2

Would the Lockout/Tagout standard apply to any aspect of this maintenance activity?

  • Correct.

    The Lockout/Tagout standard would apply to the control of any hazardous energy related to the activity not covered by 29 CFR 1910.333. For example, the Lockout/Tagout standard would require that the crane be secured from movement, and that hydraulic or pneumatic lines that could become energized and cause injury be locked out.

  • Incorrect. Actually, Lockout/Tagout is applicable here.

    The Lockout/Tagout standard would apply to the control of any hazardous energy related to the activity not covered by 29 CFR 1910.333. For example, the Lockout/Tagout standard would require that the crane be secured from movement, and that hydraulic or pneumatic lines that could become energized and cause injury be locked out.

Question 3

Was the repairman (a millwright by trade) qualified to verify that the circuit was deenergized?

  • Incorrect.

    The repairman was not adequately trained as a qualified person under the Electrical-Safety-Related Work Practices standard to perform lockout and tagout of electrical components. As a result, he could not have adequately verified that the circuit was deenergized.

  • Correct.

    The repairman was not adequately trained as a qualified person under the Electrical-Safety-Related Work Practices standard to perform lockout and tagout of electrical components. As a result, he could not have adequately verified that the circuit was deenergized.

Question 4

Would the employer be required to develop two separate energy control programs to meet the requirements of both the Lockout/Tagout standard and the Electrical Safety Related Work Practices standard?

  • Incorrect. The employer is not required to develop two separate energy control programs.

    The employer could develop and implement a single written energy control program provided that this program addressed the applicable requirements of both 29 CFR 1910.147 and 29 CFR 1910.333.

  • Correct. The employer is not required to develop two separate energy control programs.

    The employer could develop and implement a single written energy control program provided that this program addressed the applicable requirements of both 29 CFR 1910.147 and 29 CFR 1910.333.