• 250.32 ground between main and sub panel

    I am a apprentice and recently we ran 2-2-2 AL wire from a main panel on a grain bin under ground in schedule 80 PVC to a cow barn but we did not run a ground conducter with the current carrying wire. I asked if this ...
    charlesvanmeter
    last modified by charlesvanmeter
  • Can 2 pole breakers supply 2 circuits

    Say for example, you have a 120/240 V, 2 pole, 20 A breaker. Does the NEC allow this breaker to serve 2 separate 120 V circuits?
    tgammonphd
    last modified by tgammonphd
  • Basement to first floor wiring?

    I am trying to run power from basement to first floor. House has seal plate is a solid 4x8 or 6x8 Wich sits on a concrete wall. The seal plate is reassessed 6" from the edge of concrete and the wall sits in 2" from ed...
    charlesvanmeter
    last modified by charlesvanmeter
  • equipment grouding conductor used as a bonding jumper.

    Can you use a equipment grounding conductor as a means of a bonding jumper for conduit. I have always used a separate wire for the bonding jumper.   r.
    aaronlewin4
    last modified by aaronlewin4
  • MCCBs PPE or Not

    I have had a question for some time about operating molded case circuit breakers with or without PPE.  NFPA 70E states in table 130.5 that under normal conditions it is a low risk of exposure to an arc flash....
    troy.wappler
    last modified by troy.wappler
  • Smoke alarms and doors

    Smoke alarms and doors are not two separate realities. We have to flee from seeing smoke alarms and the doors of our homes as two separate realities. The synergies between these two elements, such as first-order preve...
    carretero110
    created by carretero110
  • Intravenous-Health Lounge?

    I am coming across plans for an IV drip-therapy office, where patients get hooked up to an IV.  They get nutrients, B vitamins, "immunity-boosting" vitamins, etc., it is supposed to cure a hangover....
    chiefns830
    last modified by chiefns830
  • Sprinklers Inside Electrical And IT Rooms

    Why the sprinkler could be omitted at electrical room (with specific conditions should be met) but not allowed to be omitted from IT rooms ((With the same conditions)? Also, suppose I have a light hazard room such as...
    a_safwan2001
    last modified by a_safwan2001
  • Service Disconnect

    Been having some discussions with other people in the trade, and the subject of Service Disconnects came up in regards to OCP and it's location for dwellings or in general. Some have mentioned that the first OCP devic...
    markselectric
    last modified by markselectric
  • NEC 310.104

    For those who were helpful on this post, Thank You.   Chiefns830 managed to drive me away.   Nothing that I read indicated that homeowners were not welcome to ask electrical questions.
    maynardrf
    last modified by maynardrf
  • 480vac 3ph Power Distribution

    I have a system where we are supplying a skid with 3 VFD/motors. The VFD/motors are each wired to there own fused safety disconnect.  The skid also has a fused disconnect for power supply to a 480/120 transformer...
    marc.gelinas
    last modified by marc.gelinas
  • Standby Generator Wiring

    This is in reference to NFPA 110 Emergency and Standby Power Systems.  7.12.3 states:    If the conduit's point of attachment to the EPS in on the forcing function side of the EPS vibration isolation s...
    garrys917
    last modified by garrys917
  • Line side/Load side versus Bus side/Line side

    Does anyone know the history and where (if one exists) for the official definition of "Line Side" and "Load Side"?   Countless standards such as the NFPA 70 (NEC), 70E, IEEE 1584, C37.20.2, and even electric equ...
    george.cole
    last modified by george.cole
  • VFD Input/Output Current

    If my VFD outputs more current than my motor, but is the right HP, do I size my MCP for the drive, or for the motor?
    ademko
    last modified by ademko
  • Photovoltaic - 2017 NEC 705.12(B)(2)(3)(a) and 705.12(B)(2)(3)(b)

    The way I’m interpreting this section, the Photovoltaic installation must comply with either 705.12(D)(2)(3)(a) OR 705.12(D)(2)(3)(b):   (a) says that 125% of the inverter output circuit current (can be obt...
    chiefns830
    last modified by chiefns830
  • NFPA 72 Dedicated Function Fire Alarm

    Using ICC 2012 and NFPA 72 2010 edition,  Given an occupancy that is not required to have a fire alarm by 907.2.4 and is sprinklered per 903.2.4 thus contains a dedicated function fire alarm unit for water flow ...
    blalkire
    last modified by blalkire
  • Single motor protection with VFD per Article 430.130

    Looking for interpretation of Article 430.130(A)(1) and (2) with respect to Branch-Circuit Short-Circuit and Ground Fault Protective device rating for single motor applications when a VFD is installed. The article ref...
    tom.brenner
    last modified by tom.brenner
  • NFPA 410 - Electriicaly Grounded

    NFPA 410 section 7.4.3.1 requires "To reduce the hazards associated with static electricity, aircraft shall be electrically grounded when parked in aircraft hangars."   Boeing Aircraft are statically ground...
    jeff.l.tjernagel
    last modified by jeff.l.tjernagel
  • Elevator Recall

    Does Fire Sprinkler riser's water flow switch initiate elevator emergency recall? In NFPA 72 "Table A.14.6.2.4" Typical Input/Output Matrix" shows water flow switch on first or second floor initiate elevator emer...
    zara.mosavat
    last modified by zara.mosavat
  • MC cable for PV installation

    Article 330.12 prohibits MC cable when exposed to mechanical damage. 690.31(D) allows MC cable when intalled in an area that is not readily accessible.  My client wants to install MC cable across the open roof of...
    jeffrey
    last modified by jeffrey