• Installing Extra Conductors Question

    Hello,    We are building apartments in Nevada. Does the fire alarm installer have the authority to install a wire with more conductors than the plan indicate? In our case, the plans show 18-2 for smoke det...
    last modified by andyv
  • NFPA 72 - Sound Calcs

    I am short on time and need help going in the right direction.   The AHJ wants the sound levels in each room without a horn/strobe. I indicate horn/strobes in the corridors and common spaces.   I know the ...
    last modified by wbf
  • If we install air aspirating system then there is no need of infra red beam detectors as per standard?

    We have oil rig Manufacturing warehouse of  length 128.12 , width 62.82 and height 13 meters,contractor  has proposed vesda  air aspirating  system, saying that if we install  air aspirating d...
    last modified by maqsoodasif17
  • 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 ...
    last modified by troy.cornett
  • Ionizing radiation resistant fire detection

    Does anyone know about fire detection capable to resist to very high ionizing radiation fields (10 MGy)?
    created by nsss
  • NFPA 70 for deep well pump application Class 1 Division 2

    I have a project that takes storm water (not sewage) via gravity flow into an underground storage system (all debris has been removed prior to entering storage). This water will be treated via recirculation using...
    last modified by jalmaraz
  • Arc Flash Reduction Breaker

    NEC 240.87 for arc reduction circuit breakers of 1200A or more, when applying to an emergency generator with life safety and if accidently left 'on' could cause an unwanted trip.  Is there an exception or is ther...
    created by j_w_hines
  • Pull boxes penetrating walls

    Hi everyone!   We are doing a renovation project and one of our concerns is a pull box penetrating a wall. According to one of the project managers, in Japan's standards, a pull box made of a 1.6mm-thick p...
    last modified by ejlsanpedro
  • How far should I place a smoke detector or a heat detector from a beam or sidewall? This is regarding dead air space.

    I was going through NFPA 72, 2016 Edition. In code A, they showed the proper mounting placement of heat detectors with the following figure.     Can I use the above image for smoke detec...
    last modified by shamilbb12
  • What is the distance required between two smoke detectors? Is it 7m or 9m?

    The client said it should be 7m. In other sites, they said it should be 9m. Can anyone please clarify regarding the same?
    last modified by shamilbb12

    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 ...
    last modified by arshdeep
  • Who can test a local manual pull station alarm?

    Church built in the 1960's has two pull stations that both activate one bell (same bell.)   Can the AHJ fire inspector witness the operation of these devices by the owner or is he required to hire a fir...
    last modified by reilly4562
  • 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 
    created by michelle.dyer
  • Main power supply cabling for fire alarm panels to be fire resistant?

    Hi. I happend to look at BS 5839-1, and found that fire resistant cabling is requried for not only the loop cabling to devices, but also mains power supply for fire alarm panels. I have never seen such requiremtn in N...
    last modified by minhyeong1.kim
  • Fire detector for semi-open warehouse

    Hi,   I have a warehouse about 50Wx50Lx10H m. It has only 2 external attached walls. Do we need to install the fire alarm detector?
    last modified by b.piyakarn
  • Main Lug Only Panel Fed From a Delta/Wye Transformer

    I am working in a project for a Utility Substation and I came across a question that perhaps someone in here could help me with.  I am aware that utilities don't have to abide by the NEC-NFPA70 per 90.2.   ...
    last modified by rafis
  • Energization of Electrical Equipment On a Set Time Schedule

    Some years ago a worker was completing work on a de-energized transformer.  He was electrocuted before he finished his work.  Very sad incident.   The investigation revealed that the worker tr...
    last modified by tvanhooser
  • NFPA clause for Extract fans and FCUs

    Hi, I'm trying to get the NFPA clause related to the interfacing requirement for Extract fans and FCUs, I heard that these are not required to interface until they are not supplying fresh air. Can anyone help me to ge...
    created by gbngeo13
  • NFPA 99 ( )Clarification Required

    With refer to NFPA 99 Older versions Ref Wiring Requirements Separation from other circuits .The life safety branch and critical branch shall be kept independent of all other wiring...
    last modified by vijay.r1986
  • Fire door at Transformer Fire wall

    Hi,   I have a query related to fire door at Transformer Fire wall. Anybody have any experience to provide fire door at Transformer fire wall ? Which code permits fire door at transformer fire wall as escap...
    last modified by pratik.bandyopadhyay