• Why no PPE Class on Incident Energy Analysis label?

    Referring to NFPA 70E 130.5(D) - What is the reason that the PPE category can't be included on an Incident Energy Analysis label?
    last modified by ral@livelinesafety.com
  • New Construction Low Voltage Prewiring

    Was told by DuPage County in Illinois they require all low voltage wiring to be in pipe or raceway per Nec code for 2014 and 2017. As far as I know it does not. Especially speaker wire, cat6, cat5 and RG6(coax) which ...
    last modified by caltek.steve
  • PV Disconnect Switch

    Residential PV disconnect requirements   I have a 4 wire 120/240 do I need a 2 pole or a 3 pole disconnect switch one person told me that I needed a 3 pole and run the neutral through the disconnect switch.Is th...
    last modified by power4200
  • Using Double Pole breakers as single pole in Housing Tract Residential

    I have always been taught for the past 30 years that you cannot use double pole (220/240V) breakers as single pole. When I moved into my newly built home, I ofcourse checked the checked the main panel.  When I op...
    last modified by barneyw6
  • NFPA 70E using fall protection with high ceilings...

    NFPA 70E using fall protection with high ceilings that have limited achorage points. How can additional anchorage points be added that will comply with the standard?
    last modified by kevin.elkins
  • Infra Red Scanning

    I work at a major East coast university and I want to research what the industry is using for infra red scanning and thermography.  The intended use of the equipment will be scanning electrical panels and conduct...
    last modified by johnc0310
  • when ZCV are not requirred

    I just want to ask when Zone Control Valve are not required for sprinkler system  If i have a small area need only for 4 sprinkler - do i need to inslaa ZCV for this small room      thanks a lot&...
    last modified by hdighidy
  • PV Solar connection to AC Generator Transfer SW

    I am inspecting a PV system protected by  40 amp fuses at the AC Disconnect for the PV system. The AC system has a 20 KW Generac Generator serving the hole home. The transfer sw is the main AC disconnect and th...
    last modified by wbculleysr
  • powder extinguishing system

    Hi All, regarding NFPA 17 what are the minimum density that we can apply for the total flooding (for example a room) and an object ( for example transformer) compare to NF EN 12416-2 that the minimum density is 1.2 k...
    last modified by sammy.kadouri
  • NFPA-496 7.4.10

    How to interpret the power source requirement in NFPA-496 7.4.10 "The electrical power for the positive pressure air system shall be taken off the main power line ahead of any service disconnects to the control room o...
    last modified by chenting.elec
  • NEC Training: What's in it for you?

    When it comes to NEC training, there are almost as many different providers as there are letters on the pages within the Code. What makes one provider stand out compared to the other options? What do they offer that a...
    last modified by dvigstol
  • journey man electrician

    What work can a journey man electrician do? this pertains to work on his/her employers buildings.
    last modified by jack.clark
  • Filling inside the wireway

    The article of NFPA79 clearly state the following:   13.5.2 Percentage fills of Raceways (Ducts) "The combined cross-sectional area of all conductors and cables shall not exceed 50% of the interior cross-section...
    last modified by abderrazak.dabbagui
  • Copper Busbar installation - exposure and corrosion

    In NEC article 300.37, it states that exposed busbar may be installed in areas that are accessible to qualified persons only. Does this imply that this given area must be enclosed or fenced off in some manner? Also, i...
    last modified by mylumbermill
  • NEC EGC Size Compliance for Grounded Systems Power Circuits in Conduits and/or Cable Trays

    EGC sizing for Grounded Systems of ungrounded conductors, multiconductor cable, multiple circuits, and conductors in parallel when installed in conduits or Cable Trays shall comply with NEC Section 250.122 (A), (B), (...
    last modified by manuelparedespe
  • Arc Flash Equipment Labeling Requirements

    Greetings, I am needing some clarification on what appears to be a contradictory statement pertaining to the content of the equipment labeling requirements of NFPA 70E-2015, Article 130.5(C), 130.5(D)(3), and the comm...
    Steve Benton
    last modified by Steve Benton
  • Failure Mode of GFCI

    I disassembled a "failed" GFCI.  (If you've not done so, I strongly encourage it....they are  complex.) There are "springy" metal contacts that open when the GFCI trips.  On both sides (hot and "neutral...
    last modified by mhl24
  • NEC 250.122 (A) and (B) applications and interpretations

    NEC requires to size the EGC by using Table 250.122 as indicated in Section 250.122(A), and add requirements to comply with sections 250.4(A)(5) or (B)(4) for voltage drop consideration and to provide a retu...
    last modified by manuelparedespe
  • Vacuum excavation to expose underground electrical utilities

    We use vacuum excavation to expose underground utilities to precisely locate them.  When using this technique on buried electrical utilities, we are concerned about both arc flash and electrocution if we inadvert...
    last modified by brian.britain
  • IP Rating For Cabinets in Automatic Sprinkler Room.

    What is the minimum IP rating of pump controller cabinets which are to be used in a fire pump room protected with Automatic Sprinkler system as per NFPA. Please note we are proposing a controller cabinet with IP rati...
    last modified by gm@novazen.com