• Testing of a non-UL certified transfer switch prototype

    Hello all!   I have designed and built an automated battery transfer switch that currently fits into a 70 AMP breaker box. The current setup is home breaker box -> Romex -> device -> Romex -> breaker...
    jeremiah
    last modified by jeremiah
  • Rationale and Application of 50 V Threshold in NFPA 70E

    Good Day,   In the process of setting appropriate safe work conditions for use on various pieces of electrical equipment, the team at my organization has uncovered some questions on appropriately applying the 50...
    nicholas.harknett
    last modified by nicholas.harknett
  • Removing cover from electrical panel with dead front in place

    Good Afternoon,    When removing covers from electrical panels but leaving the deadfront in place are employees required to wear Arc Flash protection and follow approach boundaries? This is commonly done fo...
    safetysaves2019
    last modified by safetysaves2019
  • Ampacities for Conducors in Cable Trays

    Conductors in a cable tray are installed per 392.80(A)(2)(d) and both ends of the conductors emerge from the cable tray and terminate in equipment with 75C rating. Since the conductors are installed per 392.80(A)...
    nsaro
    last modified by nsaro
  • Hot Water Heaters

    Greetings, Are there any NFPA mandated requirements that require HWH for emergency eyewash to be powered from stand-by system bus as opposed to "normal" system bus?  I have a system that has a normal bus supplie...
    stepandmit
    last modified by stepandmit
  • Paralled Conductors-Derate Q

    I have parallel feeders to a 800 Amp MCC in separate raceways from the distribution breaker.  Does the wire have to be derated according to Table 310.15(B)(3)(a) from NFPA 70 code.  We are having a debate on...
    matt.rudolph
    last modified by matt.rudolph
  • Garage door opener receptacle

    In the 2017 NEC, MUST this receptacle have GFCI protection?   From what I'm reading I cannot determine if they mean ONLY the garage receptacles in "storage areas, work areas, and areas of similar use."
    chiefns830
    last modified by chiefns830
  • Access floor and grounding

    Is as access floor required to be grounded?  In an office building, carpeted tiles.  Power under floor in raceway.  Non-stringered flooring spec'd (tiles screwed down at each corner) and ground straps a...
    bwy
    last modified by bwy
  • What Are You Thankful for?

    I thought that as I close out this work week I would say thank you to all that contribute to making the use of electrical energy safer, more efficient, and easily accessible. Have a blessed holiday ! 
    Steve Benton
    last modified by Steve Benton
  • *Electrical Safety Concerns*

    I thought that I would open up a discussion where viewers of this thread could share what they perceive to be the greatest electrical safety concern that they encounter or perhaps the most frustrating electrical safet...
    Steve Benton
    last modified by Steve Benton
  • RTD Wiring Requirement in C1D2 area

    I am installing temperature monitoring and alarm devices in a Class 1 Division 2 area  I'd like to get confirmation of my understanding from other professionals regarding the installation.  The alarm co...
    jon.sarrocco
    last modified by jon.sarrocco
  • When did the rule forbidding garage outlets on Small Appliance Branch Circuits begin?

    When did the rule forbidding garage outlets on Small Appliance Branch Circuits begin? I know that it's 210.52(b) in 2014, 220-3(b) in 1974, 1962, and 1959, and 2115-b in 1956.
    david_wise
    last modified by david_wise
  • Minimum Area required for Fire alarm system

    As per NFPA 72, what is the minimum required area of the room or building where fire alarm control system is not required? 
    sheraz.baig
    last modified by sheraz.baig
  • NEC 250.122(B)

    In regards to NEC 2014 250.122(B). [Conductors are based on THWN-2, 75 degree terminations and 86 degree F ambient temperature]:   Question/Condition 1: Engineer selects (1) run of (4) #350 KCMIL copper conducto...
    dmatern
    last modified by dmatern
  • Touchscreen in C1D2 location

    I have a touchscreen HMI display that I want to locate in a Class 1 Div 2 area. The display is not rated for the area so I plan to mount it in a purged and pressurized enclosure. The question is, is that good enough? ...
    thomas.black
    last modified by thomas.black
  • Aerosol Plant Flame detector ?

    Can i use Flame detector for Aerosol plant according to NFPA 30B.
    abrar.b
    last modified by abrar.b
  • i am going to active the deluge system with it and its inside

    i am going to active the deluge system with it and its inside  
    abrar.b
    last modified by abrar.b
  • ELECTRICAL ROOMS - FIRE RATING

    ELECTRICAL ROOMS - FIRE RATING I'm looking for required fire ratings of Elec Rms in office bldgs, as well as other bldg types. What is the best manual to research: NFPA 101, NFPA 75, or other? Thanks, jksjim
    jsworks
    last modified by jsworks
  • 312.2 damp and wet locations

    312.2 says in wet or damp locations to cabinet or cutout boxes shall be mounted so there is at least 1/4 inch airspace between the inclosure and the wall or supporting surface. My question is how to achieve this spaci...
    charlesvanmeter
    last modified by charlesvanmeter
  • Meter main combo wiring

    With a meter main disconnect combo. Using the main lugs from the disconnect (not one of the additional breakers in the M M combo) to run cable to a interior panel board. Would this designate my Interior panel board as...
    charlesvanmeter
    last modified by charlesvanmeter