• Maximum Transformer Primary Distance

    For a transformer, 450.14 states that where the primary disconnect is remote, it is to be lockable per 110.25 and the location field marked.  For a large building (500K-1M Sqft), is there a code limit to this dis...
    j_w_hines
    last modified by j_w_hines
  • City Refuses to Close Electric permit due to lack of UL certificate.

    Hello, we imported Electron-Beam Welding machine from EU to US. We invited UL inspector for the Field Inspection and received a lot of comments. While we working on UL's coments, our city's electric engineer refuses t...
    seyhun.ramazanov
    last modified by seyhun.ramazanov
  • Fuel Storage Room Electrical

    We have a room in a vacant building that is scheduled to be converted into a "Fuel Storage Room." The items range from 55gal drums of  hydraulic fluid, motor oil, antifreeze, and air compressor lubricant. Aside f...
    sarahw
    last modified by sarahw
  • Continual use of USB Ports in computer monitors

    USB fans plugged into USB ports located in computer monitors - I think if the fan power matches the USB port power we are OK (500mA), but not sure.   Second piece is if the monitor goes to sleep, does power to t...
    dankertj
    last modified by dankertj
  • NFPA 780 Annex L

    ADJ is defined by equation L.6.6.1.4 as the equivalent collection area of the adjacent structure which equals 40xLL. However, this is the same methodology in the determination of AL. Seems that the methodology used sh...
    kbourassa
    created by kbourassa
  • Whats the minimum size, general - use snap switch, for a 1 1/2 HP, single phase, 230 V, AC Motor ? I have searched everywhere in the codes. Not sure how to get the correct calculation. Residential Electrician, apprentice

    Whats the minimum size, general - use snap switch, for a 1 1/2 HP, single phase, 230 V, AC Motor ? I have searched everywhere in the codes. Not sure how to get the correct calculation. Residential Electrician, apprentice
    killerbabe79
    last modified by killerbabe79
  • Feeder Conductors in Parallel

    My question has to do with ampacity of feeder conductors in parallel. Parallel feeds must follow 310.10(H), last time I checked. 310.10(H) states that it's only allowed if one follows 310.10(H)(2) through 310.10(H)(...
    chiefns830
    last modified by chiefns830
  • transformer secondary and primary protection

    A 45KVA transformer located in the basement, 460 volt 3 phase primary out to a 120/208 volt 3 phase circuit breaker panel on the second floor of a 2 story building. The primary protection is a 460 volt 3 pole breaker ...
    epatterson@jmeuc.com
    last modified by epatterson@jmeuc.com
  • When am I required to wear PPE

    From the very beginning of my exposure to the NFPA 70E I have been taught that if I am inside the limited approach boundary with exposed energized conductors i have to wear appropriate ARC rated PPE.  My manageme...
    jmerati
    last modified by jmerati
  • Wound Rotor Motor Fusing (Question of the Week)

    What is the correct fuse rating to provide short-circuit protection for a 100 HP, 200 V, 3 phase, wound rotor motor? A. 200A B. 250A C. 300A D. 110A    This question is on a test for Residential Electrician ...
    rcramereleceng
    created by rcramereleceng
  • Code Question of the Week

    A dwelling has an attached garage. The garage receptacle must be GFCI protected if:   It is a 30-amp, single phase receptacle It is a 20-amp, single phase receptacle It is rated 60-amp, 240-volt, and within 6-fo...
    chiefns830
    last modified by chiefns830
  • Elevator Hoistway Branch Circuit Wiring

    Requesting clarification on NFPA 70, NEC Handbook 2017: 620.24 Branch Circuit for Hoistway Pit Lighting and Receptacle (A) Separate Branch Circuits. Separate branch circuits shall supply the pit lighting and recepta...
    rde@homcorenaissance.com
    last modified by rde@homcorenaissance.com
  • Shipping

    I work for a dredge company working aboard a vessel. I am confused by the "Extension Cord" issue. The company likes to refer to the OSHA rules as they are tied to the shore side of operations as well. Where I am only ...
    gigconroy
    last modified by gigconroy
  • 2 Chiller - redundancy

    I have two, large commercial chillers.  One will operate at any given time.  The designer is attempting to use an ATS to switch between which chiller will operate.  I'm told that there will be a "remote...
    chiefns830
    last modified by chiefns830
  • Can 2 pole breakers supply 2 circuits

    Say for example, you have a 120/240 V, 2 pole, 20 A breaker. Does the NEC allow this breaker to serve 2 separate 120 V circuits?
    tgammonphd
    last modified by tgammonphd
  • Feeder Tap Grounds in Parallel

    #250.122(G) Equipment Grounding Conductors for Feeder Taps   250.122(G) says  Equipment grounding conductors run with feeder taps shall not be smaller than shown in Table 250.122 based on the rating of the ...
    grady_g
    last modified by grady_g
  • Tamper - Resistant Receptacles

      Can you please help me regarding the 2017 NEC article 406.12 (2). Guest rooms and guest suites of hotels and motels and Exception (2). My understanding of the article, all 15 and 20 amp receptacles shall be tam...
    michael.howard
    last modified by michael.howard
  • Lightning protection from tower NFPA 70 artcle 250.60 & 106 and NFPA 780

    Lightning protection systems NFPA 780 and NFPA 70 article 250.60 and 250.106   I have a design with has multiple towers on these towers the manufacturer has lighting strike protection, the tower is aluminum they...
    c.valvo
    last modified by c.valvo
  • NFPA 25, Electric Fire Pump Test Result

    In reviewing a fire pump test report written on a CA State Fire Marshal issued form, it indicates that a non-acceptable test result was found according to section 8.3.5.5 (adopted 2011 code, which appears as 8.3.7.2.8...
    adam.salvadalena
    last modified by adam.salvadalena
  • Electrical Outlet placement for modified peninsula/island

    Hoping to get some input on electrical outlet placement on what was a raised bar peninsula that has been modified to a single level island. Pictures below are a snapshot of the electrical blueprint when the house was ...
    delbart40
    created by delbart40