Tools

Use tools, meters, and other equipment that are suitable for the voltage and current levels present when performing all electrical work. If dropped or slipped while working on live equipment, they may reduce the possibility of creating an arc flash incident. In addition, using proper torque control limits the use of excessive force being applied which could lead to the tool slipping off.

Insulated tools or equipment are designed to provide insulation from an energized part or conductor. They may have conductive parts and be adequately coated or covered by a dielectric material, or may be composed entirely of insulating materials. Insulated industrial hand tools are typically V-rated (voltage rated) stamped on the handle with an emblem of a double triangle. Such tools must be certified that meet ASTM F1505 Specification for Insulated Hand Tools and OSHA 29 CFR 1910.335(a)(2)(i) standards.

NFPA 70E 2015 130.7(D)(1) Insulated Tools and Equipment states that employees must use insulated tools when working inside the limited approach boundary. The NFPA 130.7(C)(15)(a) Hazard/Risk Category Classifications table list tasks that require insulated hand tools.

When working on energized equipment:

  • Hand tools must be rated at least 1000 VAC/1500 VDC and are tested to 10,000 VAC for a ten-fold margin of safety.
  • Use tools that are insulated to at least the level of the voltage levels that they will be exposed.
  • The manufacturer, year of manufacture, part or code number must be identified on tool.
  • All tools must be inspected/tested for damage prior to each use.
  • If tools are found to be damaged, immediately remove from service.

NOTE: Wrapping a tool in electrical tape or non-conductive material does not qualify it as an insulated tool.

Testing Meters

Electrical testing devices such as voltage meter, ohmmeter, etc., can be the cause of an arc flash incident:

  • Defective equipment:
    • probe leads that may detach and make contact with live conductors
    • failure of internal components and safety features
    • faulty readings giving false information regarding status of equipment
  • Human error:
    • probe tip slips off connection point and makes contact with live conduit
    • hand slips off probe and makes contact with live conductor
    • probe leads in wrong jacks
    • meter set incorrectly for input voltage rated on equipment
    • readings interpreted incorrectly giving false information regarding status of equipment
    • using testing equipment not sufficiently rated for the equipment being tested

Testing meters should be carefully selected on their intended use, safety features, and voltage ratings and used strictly according to the manufacturer's instructions.

 

NFPA 2015 Article 250.4 Test Instruments and 110.4 Use of Electrical Equipment requires that test instruments and the leads used for the purpose of detection of voltage need to be functionally maintained and verified.

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Figure 1: Voltage Rated Tools

 

 Using_V-Rated_Tool_on_De-energized_Equipment.jpg

Figure 2: Using V-Rated Tool on De-energized Equipment

 

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Figure 3: Voltage Tester