• Electrical Panel Lexan Covering Exposed 480VAC

    I worked for 24 years at General Motors and it was common to see exposed 480VAC in electrical panels covered with Lexan glass to prevent accidental contact. We performed arc flash studies and all of our panels were la...
    zz3l4b
    last modified by zz3l4b
  • 480vac 3ph Power Distribution

    I have a system where we are supplying a skid with 3 VFD/motors. The VFD/motors are each wired to there own fused safety disconnect.  The skid also has a fused disconnect for power supply to a 480/120 transformer...
    marc.gelinas
    last modified by marc.gelinas
  • Single motor protection with VFD per Article 430.130

    Looking for interpretation of Article 430.130(A)(1) and (2) with respect to Branch-Circuit Short-Circuit and Ground Fault Protective device rating for single motor applications when a VFD is installed. The article ref...
    tom.brenner
    last modified by tom.brenner
  • NFPA 79 Inspector needed

    I'm looking for a 3rd party inspector to inspect a machine to NFPA 79 standard in the Wisconsin area.   Any suggestions.
    mwessel
    last modified by mwessel
  • What Is Wrong With This Genset?

    david.pfau
    last modified by david.pfau
  • Instrumentation Enclosure Component Fill Volume Requirement?

    Instrumentation Enclosure Component Fill Volume Requirement?   Hello,  I work for what amounts to an industrial supplier and we produce instruments that are composed of various electrical/other components....
    jtmiller
    last modified by jtmiller
  • Knowledgeable Person

    Is there a industry excepted definition of a Knowledgeable Person.  I am working on updating my EEWP and we are looking into the approval portion and would like to have a knowledgeable person in this pr...
    jmerati
    last modified by jmerati
  • Surge Protection

    NFPA 79, 7.8.1 States that " SPD's (surge protective device) shall be provided for industrial machinery w/ safety interlock circuits to protect against the effects of overvoltages sue to lightning and switching surges...
    jeremy.bello@emerson.com
    last modified by jeremy.bello@emerson.com
  • Wire Color for Remain Energized 24VDC Conductors.

    NFPA79 specifies: 13.2.3.2 The use of other colors for the following applications shall be as follows: (1) WHITE with BLUE stripe for grounded (current-carrying) dc circuit conductor (2) WHITE with ORANGE stripe ...
    borisg
    last modified by borisg
  • Electric Griddle info.

    Hello, my company is promoting a function and we have 4 electric griddles similar to the George foreman type.  I was trying to find information on what gage extension cords are needed spanning a length of 75-100 ...
    troy.cornett
    last modified by troy.cornett
  • 300va transformer, must the core be grounded

    I have equipment using a 300va custom wound transformer.   The core is lacquered and I have to grind off the coating to ground the frame.     Is it mandatory that the core be grounded and...
  • Door Interlock as par NFPA 79 Clause 6.2.4.

    Hello,   We have separate enclosure where enclosure which contains the supply disconnecting means has mechanical interlock that door can not be open without  making switch OFF. We also have second enclosur...
    vishal_g_patel
    last modified by vishal_g_patel
  • HOA hand switch leg direct to motor starter

       There has been some debate among my coworkers lately about the "Hand" switch leg of a rotary HOA selector switch going directly to the coil of a motor starter. I have been making the case that this i...
    jfosterjrod58
    last modified by jfosterjrod58
  • NFPA 79 - RACEWAY DENSITY

    NFPA 79 Section 13.5.2 states that "the combined CSA of all conductors and cables shall not exceed 50% of the CSA of the raceway. My question is can this value be greater than 50% if the temperature of the cables in ...
    alan.morrison
    last modified by alan.morrison
  • Equipment Grounding

    In regards to NFPA 79 Chapter 8:   If multiple non-current carrying conductive parts have continuity across them, (i.e. pipe -> equipment frame -> other pipes) can I use their continuity as a ground path o...
    smckinley89
    last modified by smckinley89
  • CAN I USE GND EARTH INSTEAD OF NEUTRAL

    Hi All,   I am making a 3 Phase power meter using a MICROCHIP IC ATM90E36A. They recommend to use neutral wire as a GND reference to measure voltages at 3 hot legs but in my loads (Air Conditioners) there is no ...
    arshdeep
    last modified by arshdeep
  • MTW in Conduit?

    Can MTW wire be ran in conduit or is it strictly to be used for wiring in a panel?   We would be installing the wire between our control panel and motor and running it in conduit.
    marc.gelinas
    last modified by marc.gelinas
  • What would be the proper wire size?

    I have a feeder circuit - power coming into a terminal block rated for 175A then wired to a 50A contactor to a compressor with an RLA of 28.8A.  The terminal block states 75C wire and the compressor states use mi...
    matthew@haskris.com
    last modified by matthew@haskris.com
  • Current-currying conductor in cable

    Hi, in a multiple-conductors cable the load is unbalanced among the conductors: which wires should be considered "current-carrying" conductors?   E.g.: a jacketed cable with 7 identical wires; for the specific ...
    giacomo.gasparini
    last modified by giacomo.gasparini
  • Commercial System Inspector

    Cennox is a nationwide corporation looking for a  Commercial Systems Inspector.   Part- Time in the Cleveland,OH; North Dayton, OH;  Full- Time in Richmond, VA;  Norfolk, VA; St. Louis, MO 
    michelle.dyer
    created by michelle.dyer