• XP or not XP?

    I'm building a machine for a client that requires a 50%/50% Alcohol and Essential oils mixture to be misted on a product in a confined space (the machine enclosure). If we ventilate (extract with XP duct/fan system) t...
  • Electrical Safety Programs

    Most of us have probably read the standards and should all agree that developing safety policies, programs, and procedures are the responsibility of employers but who is it in your workplace that ultimately develops t...
    Steve Benton
    last modified by Steve Benton
  • Conduit penetrations in Hazardous spaces

    What type of conduit sleeve is required for a conduit penetration into an unclassified space from a Hazardous Class I Division I space? How do we prevent gases from migrating around (inside and outside) the sleeve int...
    last modified by kbourassa
  • Lighting Inverter Tripping

    In testing the inverter, when the utility input is off, simulating a power outage and exterior lights come on, it quits.  All lighting is LED and by all indications the inrush is the problem.  The lighting i...
    last modified by j_w_hines
  • Solar Pole Lighting Voltages

    Hello I am developing a solar pole light for walkways.  It is self contained, contains Lithium Ion batteries, and not connected to the grid.  I am wondering at what voltages (solar panel, battery or LED dri...
    last modified by dleverton
  • Is tray cable in cable tray considered exposed?

    DEFINITION: Exposed - (as applied to energized electrical conductors or circuit parts) Capable of being inadvertently touched or approached nearer than a safe distance by a person. It is applied to electrical conducto...
    last modified by ral@livelinesafety.com
  • Per NFPA 70E 130.2(B) Energized Work Permit if you deenergize the breaker in a bucket and the only power left is the incoming from the stabs to the top of the breaker is the work permit required?

    Also if you have multiple VFD's in one cabinet and you are changing one but the rest are powered up would a wok permit be required?
    last modified by kris.mcquiggan
  • 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...
    last modified by jeremy.bello@emerson.com
  • Fire Protection Design of Installed PV panels

    In my country there is no regulation on installation of PV panels. My question is regarding the ones that are already installed, in this moment they don't follow NFPA 1 nither NFPA 70. How can I design a fire protecti...
    last modified by catac_16
  • Absence of Voltage Testing

    According to the NFPA 70E, when are noncontact test instruments permitted to be used to verify absence of voltage in circuits less than 1000 volts? 
    Steve Benton
    last modified by Steve Benton
  • Operating Generators and NFPA-70E

    I am being challenged by our work group regarding working on a HV generator set (11kV) that is in close proximity to other operating generators at 11kV within a powerstation.  From NFPA-70E Table 130.7(C)(15)(a) ...
    last modified by alan.peet
  • GFCI Below Sinks - why not?

    Anyone know why GFCIs are not required for equipment located below sinks such as in-sink waste disposers and trash compactors? I don't see a requirement in 210.8 and other sections such as 422.16(B)(1) and (2). Was cu...
    last modified by carl.mister
  • Wire Color for Remain Energized 24VDC Conductors.

    NFPA79 specifies: 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 ...
    last modified by borisg
  • TVSS how to install

    A TVSS should be install. On the Load side or line side of the breaker.
    last modified by jrendon6861
  • that establishes nfpa -20 on the electrical supply of the controller for fire pump on the top or the lateral supply of the controller. can you clarify what the nfpa says about it

    that establishes nfpa -20 on the electrical supply of the controller for fire pump on the top or the lateral supply of the controller. can you clarify what the nfpa says about it
    last modified by mildnern
  • EM Generator Output Board Main, ERMS

    This is the generator output board main showing standard mode and ERMS mode.  If ERMS left 'ON' and power outage, the breaker will trip on inrush. Our generator rep has seen an output breaker accidently left open...
    last modified by j_w_hines
  • NFPA 780:2017 A. sideflash distance from overhead wire

    Hello can anyone explain me the example given  in this section? In particular the second figure and why there are different values of 'n' depending on the distance from middle point. Thank you!
    last modified by scaputi
  • Low voltage plenum cables in NYC

    For a single family residence in NYC, is there an exemption to running low voltage plenum rated cables in an HVAC plenum? Or is it an absolute code requirement to run plenum rated cable in these spaces?   Thank...
  • Summary of Code Requirements or Checklist

    Does anyone know of a checklist or an inventory or requirements per code that may apply to a specific industry or business. What I am really looking for is a summary list with requirements per each code. Something sim...
    created by nicolas.monroy
  • Cable Tray Transverse Installation

    NEMA VE-2 states that metallic cable trays can be installed transversely (on their sides) but the NEC does not address this type of installation under 392. The manufacturers provide no structural or load ratings based...
    last modified by joe.turner