General Requirements >> Electrical Circuits and Distribution Boards

Electrical Circuits and Distribution Boards

Text version of flowchart:

Note: Typically all levels may be fed by more than one source.

There are two sources of electrical power used during building and repair of a vessel -- shore side and vessel generated. (See diagram).

The potential for electrical shock hazards is greater in shipbuilding and repair than in other industries, because workers stand on metal decks and often work in a wet environment. Work on or around energized electrical equipment can expose workers to electrocution, burns, or electrical shock. Before work is performed, energized equipment must be guarded, deenergized, or appropriate PPE used to prevent worker exposure. [29 CFR 1915.181, 29 CFR 1915.157(c)]

Note: 1910 Subpart S: Electrical and the National Electric Code (NFPA 70) do not apply to the vessel's electrical system.

Use of portable electrical tools and lighting can also be found in the following modules:

For shipbuilding:

For ship repair:

Note: Confined space entry is one of the leading hazards associated with barge cleaning. Review the Ship Repair: Confined or Enclosed Spaces and Other Dangerous Atmospheres chapter for information on how to protect workers from this hazard.

Figure 1: Improper practice - Faulty breaker box presents shock hazard

The Electrical Circuit and Distribution Board Standard [29 CFR 1915.181] applies to the vessel's permanently installed electrical circuits and distribution systems. Temporarily installed electrical systems (such as extension cords, portable service panel, "spider box") used for repairing of the vessel is covered in Tools and Related Equipment [29 CFR 1915.132] and General Working Conditions [29 CFR 1915.82 and 29 CFR 1915.83].

Figure 2: Portable distribution panel, "spider box" used to supply temporary electrical power

Potential Hazards

  • Worker electrical shock, burns, or electrocution due to contact with or near to energized electrical equipment.
  • Falls from elevations.
Figure 3: Circuit breakers in panel box can be used to deenergize circuits (and appropriately tagged) before working on the circuit

Requirements and Example Solutions

  • Before work is performed on circuits, except those being tested or adjusted, circuits must be deenergized and checked at the point where work will be performed to ensure the circuits are actually deenergized. [29 CFR 1915.181(b)]
  • When testing or adjusting energized circuits, a rubber or other suitable insulated deck mat must be used. [29 CFR 1915.181(b)]
  • Deenergizing the circuit must be appropriately completed by opening the circuit breaker, opening the switch, or removing the fuse. [29 CFR 1915.181(c)]
  • The circuit breaker, switch, or fuse location must be tagged to indicate work is occurring on the circuit. Such tags must not be removed nor the circuit energized until the work has been completed. [29 CFR 1915.181(c)]
  • When work is performed immediately adjacent to exposed energized parts, these parts must be covered (for example, insulated) or other equally safe means provided. [29 CFR 1915.181(d)]

Note: Control of Hazardous Energy Sources (Lockout/Tagout) standard [29 CFR 1910.147] does not apply to Ship Repair.

  • Insulating materials (such as mats and gloves) should be periodically tested or inspected.
  • All electrical tools or equipment should undergo a visual inspection before use.
  • All portable electric hand tools and temporary lighting systems should utilize Ground Fault Circuit Interrupters (GFCI).
  • Electrical tools and equipment should correspond with the requirements of the job.
  • Electrical equipment and tools should be used with proper circuit protection for the voltage and amperage used.
  • Only qualified electricians should attempt repair of electrical tools and equipment in use.
  • A Ground Assurance Program should be in place for all electrical tools and equipment used including:
    • Records of tools inspected and repaired.
    • Records of electrical boxes inspected and repaired.
    • Records of electrical extension cords inspected and repaired.
    • Recall of records of the above.
  • The requirements of the Ground Assurance Program should be performed on a regular basis.