• Lifepo4 safety

    I live off the grid and in need of new battery's for my solar system. After a long study I believe a Lifepo4 system would be the best alternative for my needs. Lifepo4 has a safety factor that is so much better than a...
    scberd
    last modified by scberd
  • Cell tower cable running up have equipment grounding conductor

    I have monopole cell tower. The tower has DC conductor cables that run from equipment on ground to cell tower antennas, RRUs, etc up top. Kind of like this: or like this in web link below:   https://wireless...
    apurvadave
    last modified by apurvadave
  • NEC 2014 grouping

    Assume that two SWGRs A and B are in compliance with NEC 2014 Section 230.2 first paragraph which says:   For the purpose of 230.40 Exception no. 2 only, underground sets of conductors, 1/0 AWG and larger, runni...
    apurvadave
    last modified by apurvadave
  • NEC 2014 Section 230.40 exception no. 1

    Attached sketch shows building layout bottom left corner, electrical room detail bottom right corner and Riser at top.   Building layout shows Vacant space which has not been filled and Tenant A space occupancy ...
    apurvadave
    created by apurvadave
  • Trough busbar bonding methodology

    I have metallic trough load side of service disconnect means whose enclosure needs to be connected to the equipment grounding conductor. The trough has equipment grounding bus bar inside it.   In attached Figure...
    apurvadave
    last modified by apurvadave
  • Two services multi occupancy building

    Attached sketch shows utility xfmr1 200A 480/277V existing which feeds the existing fdr #1 electrical room in multi occupancy bldg. The plans now show new xfmr2 800A 480/277V which feeds thru new fdr #2 Electrical R...
    apurvadave
    last modified by apurvadave
  • 230/400V Color code

    Hi, my name is Andres, I m a student in electromechanical engineering, I have a doubt about the color code in voltage system, I know that 120/208/240V is: phase A= black, phase B=red, phase C= blue and nuetral=white, ...
    andrescr54
    last modified by andrescr54
  • Main Bonding Jumper Location and Main service Disconnect Residential

    Hey guys,  I'm doing a 3600 sq ft residential job where there is 1800 up and almost 1800 finished basement. The homeowner wants the panel located in the utility room in the basement which is 35' (cable length) aw...
    jeff_schirmer
    last modified by jeff_schirmer
  • What are the guidelines for location of an emergency shower or eyewash station in proximity to electrical equipment and enclosures?

    What are the guidelines for location of an emergency shower or eyewash station in proximity to electrical equipment and enclosures? Is the location as it exists dry, damp or wet type (NFPA70 NEC2017 100)?  Will ...
    wgrayg
    last modified by wgrayg
  • Electrical Outlet in Unconditioned Sunroom

    Hello,   We are building an addition in Devon that is basically just an unconditioned sunroom, only to be used in the spring and summer. It has a good number of outlets already, but there are 4 locations where ...
    kendraajohanson@gmail.com
    last modified by kendraajohanson@gmail.com
  • metallic conduits for pv under roof sheathing

    In search of any reference to installing residential pv system and fastening metallic conduit to and distance required from underside of wooden roof sheathing.
    mkidwell
    last modified by mkidwell
  • Cell tower structural work

    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 t...
    apurvadave
    last modified by apurvadave
  • 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...
    safedesign1
    last modified by safedesign1
  • 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...
    jesus.rodriguez1808
    last modified by jesus.rodriguez1808
  • 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?&#...
    gbstand
    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...
    apurvadave
    last modified by apurvadave
  • 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...
    apurvadave
    last modified by apurvadave
  • 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...
    seve.anderson
    last modified by seve.anderson
  • 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)
    ernestorene
    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...
    zeno
    last modified by zeno