• 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
  • 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
  • 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
  • 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
  • NFPA 70 517.31(B) (2014) downstream distribution system

    NFPA 70 517.31(B) (2014) says "one transfer switch and one downstream distribution system shall be permitted to serve one or more branches in a facility with a maximum demand on the essential electrical system of 150 ...
    dan@spectrumsystem.com
    last modified by dan@spectrumsystem.com
  • Double Tapping Breakers?

    What type of breakers are available today that will allow "Double Tapping" in a residential breaker panel?
    david.sparkes
    last modified by david.sparkes
  • Does the NEC allow for the use of nonmetallic electric conduits in plenum of a confined space in a building?

    The NEC don't allow for the use of nonmetalic electric conduits in plenum (open space above false ceiling used for return air) in order avoid the convey of smoke and/or fire to other parts of the building. Is this ap...
    abdulazizabuali
    last modified by abdulazizabuali
  • 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
  • Are sealed, waterproof wire-to-wire splices in approved junction boxes below the electric datum plane but above the waterline compliant with NEC 555.9 on fixed piers?

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    ttrewyn
    last modified by ttrewyn
  • I'm trying to locate the Code reference that states "Cables cannot use components of another trade as direct support."

    I'm trying to locate the Code reference that states "Cables cannot use components of another trade as direct support." We have a Maintenance person that keeps using the Fire Suppression pipes and Heat Ducts to suppor...
    tmulanix
    last modified by tmulanix
  • Electric Room Lighting

    Is there a minimum lighting level required?   The energy guys in CA have decreed that for 2020 electric room lighting is reduced to 0.4 watts/sqft with 0.2watts/sqft for specific task area lighting allo...
    j_w_hines
    last modified by j_w_hines
  • PPE for HVAC Technicians

      I work for an HVAC service and installation company providing service on residential, light commercial and industrial equipment. We have acknowledged that our current uniforms are lacking in the correct level o...
    rmiller@hamstraac.com
    last modified by rmiller@hamstraac.com
  • US-Federal low voltage safety reqs.

    Hallo everyone! Can anyone tell me if low voltage electrical safety is regulated on the US-federal level and if so, where (CFR, etc.)? I would really appreciate your support!
    l.buhociu
    last modified by l.buhociu
  • 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
  • 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
  • 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
  • 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
  • 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
  • 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