• 240.21 feeder tap directly to utilization equipment?

    Since the 2014 edition, 240.21(B)(1)(1)(b) has allowed a 10 ft feeder tap to terminate on "equipment containing an overcurrent device" as an alternative to terminating directly on an OCPD.   I would like to conn...
    last modified by cfharr
  • What is the permissible gap of an opening for a ceiling product or tile when running wires though a tile into a Ceiling that is being used as a plenum?

    There is a product that we want to install in a ceiling in a Healthcare facility and understand the requirements of firestopping for cables but what is the permissible gap for an opening to limit the spread of sm...
    last modified by safedesign1
  • 2020 NEC Definition

    I have a question on the 2020 NEC code – definition of a term.  In Article 100 (70-35)  there is a definition for “Dwelling Unit”.  It states: A single unit ….. My question is ...
    last modified by apshulick@ieee.org
  • Ground Tied To Neutral Bar. Please Help.

    Good Afternoon,        I have a question hopefully I can get some help on. I was troubleshooting a recepticle in co-op apartment that is not working. I went to the circuit breaker panel and when I...
    last modified by jesus.rodriguez1808
  • Storage Batteries Art - 480

    The question is in Article 480.10 (E) Egress, "rooms designated as battery rooms" do we have a definition of a battery room ? I didn't find one in Art- 480 or in Art -100 . The requirement to have doors that swing in ...
    last modified by glillmar
  • 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...
    last modified by c.valvo
  • Code Compliance of Existing Installation

    Is anyone aware of a NFPA code/standard or other citable industry authority that generally discusses that code compliance for an existing installation is determined by the code in effect at the time of construction?&#...
    last modified by gbstand
  • Cell tower

    I have existing monopole tower for antenna which is grounded and bonded.   Now the structural engineer is going to place long shaft metal plate metallic on each side of the monopole tower by drilling holes in to...
    last modified by apurvadave
  • Lab Natural Gas Serrated Hose Nozzle; Hazardous Zone

    For a lab with a serrated hoze nozzle and valve for natural gas used in heating small burners, is this a hazardous zone and if so is there a hazardous zone diagram?  NFPA 497 offers some help, but not specific to...
    last modified by j_w_hines
  • Light above shower

    In a residential bathroom is the light over the shower required to be GFI protected?
    last modified by davidvartanoff
  • grounding electrode conductor connection to concrete encased electrode

    NEC 2014 Section 250.52(A)(3) states that 1/2 inch or larger rebar bonded by tie wire (20 ft or more) can be used as the grounding electrode. When attaching the grounding electrode conductor to the rebar to be encased...
    last modified by apurvadave
  • Article 220-22

    Hi, i would like to know article 220-22 still available in NEC? as we can't find in our book.  Thanks
    last modified by cl_yeoh
  • Could someone tell me if this is safe?

    Hello all.   I have an easement on my property that runs from an electrical pole on the road, back, underground about 800 feet to a neighbors yard where it stops at a transformer. There is a creek the runs perpe...
    last modified by seve.anderson
  • Installing Ethernet In My Home

    Hello,   I'm looking to install ethernet in my ~45yo house. Right now I'm looking to use unshielded Cat6a cables. I've read that 16-inch spacing between the ethernet cabling and my house's electrical wiring is b...
    last modified by benoechsli
  • NEC 220.87 : KW or KVA?

    NEC 220.87 allows for the existing load to be used for load calculations as follows: The maximum demand data is available for a 1-year period. The maximum demand at 125% plus the new load does not exceed the ampacit...
    last modified by ryan.h
  • UL

    Do the electrical components of a Tunnel Boring Machine for a tunnel construction in Virginia have to be UL approved or listed?. The TBM will be mining in gassy conditions (C1D2)
    last modified by ernestorene
  • SCCR with control panels fed in series

    I am trying to interpret correctly the logic of the SCCR method suggested in NEC 409.110 (4).b  which is the UL508A SCCR Calculation. According to this method, all the components in the feeder circuit would defin...
    last modified by zeno
  • Zone 22 device in Zone 2 area

    A process room contains a piece of machinery rated Class I Zone 1 internally, Zone 2 externally. An auxiliary piece of equipment rated Class II Zone 22 is being added. What are the requirements for the Zone 22 item; d...
    last modified by wanda.earll

    A customer is installing a permanent Above Ground pool.   He is asking to install on the ground perimeter LED strip "tape" lighting. ¿Is it allowable to do it, if using a Listed Class 2 LED driver?  ...
    last modified by abetovr
  • Existing Electric Room 110.26

    Would the NEC 2017 110.26 C 3 require 2 doors for an existing electrical room with a 1600 amp service if the only new work is to add a  breaker feeding a new distribution board in a new Electrical room? Currently...
    last modified by inspectorq