General Or Gc Electrical Safety
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General Or Gc Electrical Safety

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Construction Electrical Safety.

Construction Electrical Safety.

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General Or Gc Electrical Safety General Or Gc Electrical Safety Presentation Transcript

  • Electrical Safety
  • AGENDA
      • Electricity's Beginning Onsite
      • Temporary Power/Lighting
      • GFCI vs. Circuit Breaker
      • Power Tools
      • Safe Guarding Permanent Power
      • Energized Work
  • Electricity’s Beginning Onsite
  • Electricity's Beginning On Site
    • The First Point of inspecting an electrical system is at it point of origin (1926.404(c))
    • Ensure Overhead Lines (insulated) will be more than 8 feet away from future or existing buildings (NEC 225-19).
  • Electricity's Beginning On Site
    • Ensure Service entrance lines have appropriate clearance distances from the ground (NEC 225-18)
      • 10’ sidewalks, accessible to pedestrians only, ect.
      • 12’ over residential property and driveways no subject to truck traffic
      • 15’ Same as 12’ but when voltage exceeds 300V
      • 18’ Over public streets and areas subject to truck traffic
  • Electricity's Beginning On Site
    • Ensure the connection at the weatherhead is secure and seems capable of safely holding.
    • Ensure underground services are protected from damage (NEC 230-49 refers to table 300-5)
  • Temporary Power
  • Temporary Power
    • After the Service entrance has been confirmed as safe the next step is to follow the conduits to the first Panel
  • Temporary Power
    • Ensure Appropriate warnings and Labels are in place
      • Flash Hazard (NEC 110.16)
      • Danger High Voltage (110.34 (c))
      • For rooms and other guarded locations – Qualified Persons only (NEC 110.27(c))
      • Reference Index of NEC:
        • Labels Required and Warning Signs
  • Temporary Power
    • Open the Panel and ensure:
      • That no energized parts are accessible (1926.405(d))
      • Circuits are identified for disconnecting purposes (1926.403(h))
    • Verify that all circuits are in the “on” position.
    • This is especially important in verifying that an effective lockout/tagout system is in place.
    • If a circuit is off, ask and verify why???
    Temporary Power
  • Temporary Power
    • Ensure that access to electrical rooms and panels are limited to qualified persons NEC 110-27
  • Temporary Power
    • Ensure Temporary Power (Plugs) are separate circuits from Temporary Lighting. (1926.405(a)(2)(ii)(c))
  • Temporary Lights
    • All bulb types must be protected from accidental contact or breakage at all times. (1926.405(a)(2)(ii)(E))
    • Any empty light socket that does not contain a bulb exposes energized parts that can be a violation of 1926.416(a) or 1926.403(i)(2) exceptions listed A-D
  • Temporary Lights
    • Temporary Lights are to be installed so as to protect the conductors from damage
      • Hang fixtures as designed and not with conductive material. 1926.405(a)(2)(ii)(f)
      • Flexible cords are permissible if protected correctly. 1926.405(a)(2) – (ii)(I) and (ii)(J)
  • GFCI vs. Circuit Breakers
  • GFCI vs. Circuit Breakers
    • GFCI Specifications
      • Will trip at 4-6mA
    NOTE: A Ground Fault Circuit Interrupter (GFCI) limits the duration of an electrical shock to a period considered safe for healthy people. It does not prevent electric shock. This device does not protect against electric shock due to contact with both circuit conductors or a fault in any wiring supplying this device.
  • GFCI vs. Circuit Breakers
    • Required to protect all Temporary Power circuits.
      • Extension Cords become “temporary Power circuits” when plugged into permanent Receptacles.
  • GFCI vs. Circuit Breakers
    • Circuit breakers are Overcurrent protection devices which is one part of the overcurrent protection system.
    • Breaker/Fuse – Wire – Device
  • GFCI vs. Circuit Breakers
    • GFCI for Portable Generators
      • Required at 5KW (LOI 8/24/77)
      • Frame not required to be grounded NEC 250.34 and 1926.404(f)(3)
    • GFCI Circuit Breakers
      • For any Voltage
  • Extension Cords
  • Extension Cords
    • NEC References:
      • 240.5 Overcurrent Protection
      • Table 400.5(a) Flexible Cord allowable amps
      • Or 240.5(b)(3) extension cords considered protected when applied within the extension cord listing requirements
  • Extension Cords
    • guide for cords less than 50 ft.
    • #12 gauge - 1920 watts - 16 amps – large bench saws
    • #14 gauge - 1440 watts - 12 amps - portable power saws, routers
    • #16 gauge - 840 watts - 7 amps –Belt Sanders
    • , recip saws
    • #18 gauge - 600 watts - 5 amps - drills, small sanders
  • Extension Cords 25A 14A 9A 7A 10 17A 8.5A 5.7A 4.25A 12 11A 5.5A 3.7A 2.75A 14 50' 100' 150' 200' Cord Size Extension Cord Length Extension 120 V Extension Cord Maximum Ampacity
  • Extension Cords
    • Prohibited Uses 1926.405(g)(1)(iii)
      • as a substitute for the fixed wiring of a structure
      • Where run through holes in walls, ceilings, or floors.
      • Where run through doorways, windows, or similar openings not protected from pinch points.
      • Where attached to building surfaces or concealed behind walls, ceilings, or floors
  • Extension Cords
    • Shall be designed for hard or extra-hard usage.
      • 1926.405(a)(2)(ii)(J)
      • NEC Table 400.4
      • Common Examples include – S, SO, SJ, SJT
    • Shall be used only in continuous lengths without spice or tap. 1926.405(g)(2)(ii)
      • #12 or larger may be repaired if spice retains insulation and usage characteristics
  • Extension Cords
    • NEC 400.21 Insulation shall not be less than specified
      • If a visible amount of insulation has been removed it is in need removal or repair
  • Power Tools
  • Power Tools From NFPA 70E 110.9(B)(1)
    • Portable equipment must be handled in a manner which will not cause damage. Flexible electric cords connected to equipment may not be used for raising or lowering the equipment.
    • Flexible cords may not be fastened with staples or otherwise hung in such a fashion as could damage the outer jacket or insulation.
  • Power Tools From NFPA 70E 110.9(B)(3)
    • Portable cord and plug connected equipment and flexible cord sets (extension cords) shall be visually inspected before use on any shift for external defects:
      • Loose parts
      • Deformed or missing pins
      • Damage to outer jacket or insulation
      • Evidence of possible internal damage
  • Power Tools
    • If there is a defect or evidence of damage to any electrical tools or equipment…
    • Take it Out of Service
    • Imagine an employee dies while using the Power tool that you repaired.
    • Fatality at Trussville High
  • Ladders….
      • Portable ladders must have non-conductive side rails if they are used where a workers or the ladder could contact exposed energized parts.
      • Keep all ladder parts at least 10 feet away from overhead power lines
  • Controlling Permanent Power Through an effective Lock out / Tagout System
  • Controlling Permanent Power
    • Prior to Energizing Permanent Power There are a few things to check
  • Controlling Permanent Power
    • Check Main Switch Gear for Empty Conduits
      • Why are they empty?
      • Are they capped?
      • Will Duct Tape work?
  • Controlling Permanent Power
    • Once the gear is energized there should be no reason to re-enter.
      • Re-entering energized gear would require a scheduled “shut-down” with local utility company.
      • Or Gear must be designed to shut-down in sections.
  • Controlling Permanent Power
    • Check to Verify Lockout/Tagout Equipment is available.
    • Is there a LO/TO plan, who is the authorized person(s)?
    • Reference NFPA 70E 120 Establishing an Electrically Safe Work Condition
  • Controlling Permanent Power MSG EQ DP2 DP1 PP LP HVAC
  • Energized Work
  • Energized Work From NFPA 70E 130
    • Safety Requirements are the same wither the employee is working on or near energized parts
    • Voltage Testing, Trouble Shooting, working in a panel with the main in the off position but the lugs are energized.
  • Energized Work
    • You must have justification to work on energized circuits or parts
      • In short, if you are going to put other people’s lives in danger by turning off the power – you have justification.
      • A work permit and Job briefing/planning checklist must be completed before working energized
  • Energized Work
    • If there is any chance circuits or parts may be energized, they are to be treated as energized until verified as de-energized, meaning PPE required.
  • Energized Work
    • Use barricades to prevent or limit access to work areas with un-insulated energized conductors or circuit parts
    • Or an attendant shall be stationed to warn and protect employees
  • Topics Discussed
      • Electricity's Beginning Onsite
      • Temporary Power/Lighting
      • GFCI vs. Circuit Breaker
      • Power Tools
      • Safe Guarding Permanent Power
      • Energized Work
  • QUESTIONS?