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Type: Posts; User: Mike01

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  1. Replies
    12$$
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    446

    Poll: Transfomrer or First Disconnect?

    Bonding preference:
    @ the transformer?

    @ the first disconnect?

    Just curious on preferences / advantages / disadvantages to one vs. the other??
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    3$$
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    291

    Cable Tray Parallel Feeder Ground Conductor

    When parallel conductors are installed in cable tray [using 1/C tray rated cables triplexed] is a ground required for each set or one for the entire circuit of parallel conductors? I was on a job...
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    6$$
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    468

    LVPCB

    Ron,
    I will post the TCC when I have a chance the breaker is a LVPCB with 1600A frame and sensor, the LT setting has been adjusted to 0.5 [800A]. I understand the actual fault current [as...
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    6$$
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    468

    TCC - Equipment Protectoin

    In looking at a coordination study I noticed the following:
    Main switchgear consist of 480V ANSI Sw. Gear. [single ended] with LVPCB's and electronic trip units

    Feeder No.2 is a 800A feeder with...
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    2$$
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    247

    MWBC & Voltage Drop

    Have a friendly discussion in the office on this one but trying to work out the math part of it. With a MWBC [typically for lighting] I see a lot of 277V fixtures connected to a 480Y/277V MWBC with...
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    2$$
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    483

    MV Equipment Grounding Conductors

    Is an equipment ground in a MV 13.8kV sized any different than in LV systems, do you refer to 250.122? Looking thru. 250.180 it discusses grounded conductors and in 250.184(B)(8) indicates that it...
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    6$$
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    545

    MWBC - Stray Voltage

    On a multi wire branch circuit [from a 208Y/120V panel fed from a 30kVA xfmr] with one breaker / phase turned off, there is still a reading of 24V, measured at the receptacle? Sounds to me like a...
  8. Replies
    3$$
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    289

    Conductor Volume?

    When calculating box fill, where can I find or better yet how does one calculate the volume of a conductor larger than a #6 the maximum indicated in table 314.16[B], where it terminates to a device...
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    4$$
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    352

    312.6 Wire Bending??

    312.6 refers to wire bending, however there are no bends in the cable it will enter the enclosure and then terminate on the lugs, it will not be entering and leaving the enclosure, or "bending"...
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    4$$
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    352

    Minimum Space encosure to lug..

    I was looking [I thought there was] for a table that indicates the minimum dimension form the termination lug to the enclosure wall based on the cable size and quantity per lug. For some reason I...
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    2$$
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    572

    "Heavy Duty Lamp Holder"

    How would I find out if a fluorescent lamp socket complies with NEC Article 210.21[A] for heavy duty lamp holder?
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    3$$
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    421

    Building Addition Grounding 250.50[2]

    In 250.50[2] Metal Frame of the Building or Structure for a grounding electrode system is every column of the building required to meet one of the three requirements? For example I am working on a...
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    9$$
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    576

    Overlap / Coordination

    Looks like this is a Molded Case Circuit Breaker [UL489] with an adjustable electronic trip unit [310] [LSI], it appears the instantaneous on this unit cannot be disabled due to the fact it is a MCCB...
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    1$$
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    232

    Buck Boost Xfmr OCPD?

    having a friendly debate with a co-worker about a A BB xfmr. OCPD from 208-240 with and wanted to get you thoughts / opinions at 2kva [16x32 voltage windings] with the max secondary amps at 62.5 and...
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    1$$
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    354

    Cable Tray and Grounding

    I was on a project site where 3-1/C cables were used in triplex in tray to serve equipment and only one-EGC was run for the parallel set of conductors, in looking at the code it appears that a ECG is...
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    5$$
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    346

    Garage?

    Bob, I agree I would like to use the ventilated requirements for minor garage however under minor garage it talks about gaseous fuels "will not be dispensed or transferred" that is where I am stuck...
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    5$$
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    346

    511.3[C]

    Correct, the section [C] that refers to Major Repair Garages indicates that "flammable liquids will not be dispensed, but repair activities that involve the transfer of such fluids", since I have no...
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    5$$
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    346

    Hazardous Locations / Classifications

    Looking at a project where there will be vehicle testing, and includes pit areas, typically the vehicle is driven into the facility tested and removed however there are cases where they bring in fuel...
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    1$$
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    242

    Xfmr. Secondary Conductors

    I was looking at an exisitng one-line diagram and noticed sometihing [unrelated to the project at hand but got me thinking], there is an automatic transfer swtich connected to a set of transfomrer...
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    2$$
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    429

    Two Speed to VFD?

    Can a standard 2-speed / 1-winding motor operate on a single VFD? The thought was to abandon the low speed connect the VFD to the high speed only and set the max. min to a level where the motor will...
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    4$$
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    426

    Thanks.

    Wow, I missed that one learned something new today. Thanks everyone.
  22. Replies
    4$$
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    426

    Receptacle installation

    While on a project site the electrician installed backboxes with extension rings however with the additional wall covering the receptacle when installed flush is not completely recessed into the...
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    1$$
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    268

    Generator OCPD Size

    in reviewing two proposals for new generators [500kVA/400kW] one manufacturer is providing a 600A breaker the other an 800A breaker at 500kVA @ 480V approx. 600A each are indicated as standard 80%...
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    3$$
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    539

    Flexible Cords above Ceilings?

    Article 400 "Cords" indicates flexible cords cannot be installed above suspended ceilings [with exceptions], however does this inlcude low voltage cabling from a power supply? for example where I...
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    6$$
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    576

    Equipment Specs.

    Gar,
    The equipment in question is a piece of kitchen euipment [coffee] The manufacturers literature indicates a 220V circuit, the engineer designed in a buck / boost xfmr. to achieve the 220V, [not...
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