Forums » Electrical Engineering

Generator

    • 38 posts
    March 4, 2019 8:20 AM PST
    Hi all,

    I need to install one generator to the existing main panel but I can not find spare breaker or space to connect?

    It would also not good idea to install only one panel for only one generator. Any idea?
  • March 4, 2019 11:20 AM PST

    Deleted

    accidental double post


    This post was edited by Deleted Member at March 4, 2019 11:23 AM PST
  • March 4, 2019 11:20 AM PST

    RR - This is so generalized is it unanswerable.  A lot more context is needed.

    For example:

    Is the generator in the 1MW range or the 5KW range

    120/240V or 13.8KV

    Are the loads iron lungs and alien containment fields OR convenience lights for the kid's video games

    Does the application need a transfer switch

     "It would also not good idea to install only one panel for only one generator."

    Why not?  If the generator is needed (not wanted - but needed) and a new panel is the only available option - then yes, you put in the panel.

    So, how about some more information.  Tell us about the installation


    This post was edited by Deleted Member at March 4, 2019 11:22 AM PST
    • 19 posts
    March 4, 2019 11:29 AM PST
    Rajish Rakish said:
    Hi all, I need to install one generator to the existing main panel but I can not find spare breaker or space to connect? It would also not good idea to install only one panel for only one generator. Any idea?

    take a small sub panel and shift the one or two breakers to small new sub panel. Install new breaker in the empty space main panel. This is an alternative way.

    • 37 posts
    March 4, 2019 11:47 AM PST

    NEC recommends 20% of the panel left for future. So a 30 circuit house or commercial space requires a 40 circuit panel, and a 31 circuit space requires a sub panel. Is it really full?  I do not think so?

    • 38 posts
    March 4, 2019 10:00 PM PST
    David Welson said:
    Rajish Rakish said:
    Hi all, I need to install one generator to the existing main panel but I can not find spare breaker or space to connect? It would also not good idea to install only one panel for only one generator. Any idea?

    take a small sub panel and shift the one or two breakers to small new sub panel. Install new breaker in the empty space main panel. This is an alternative way.


    Yes, that I mean, if possible. Thanks
    • 200 posts
    March 6, 2019 7:35 PM PST

    Thanks for the suggestion of this topic, Rajish, but some of your questions are very short with few or no details becoming more and more difficult to have a satisfactory reply. Anyway...

    As Ronnie Rana advised there is always need to have spare/space left in all installations otherwise in near future you will face the same problem again and with a higher cost and more wasting time: decommissioning/demolishing old panels and installing new panels.

    But now you have an opportunity to make the "right thing" - so do not miss such opportunity.

    Ronnie Rana advised 20% of spare/space as per NEC, but I know you are working in India, a non-NEC country. Internationally many industries use their own code and the most frequent one is:

    10% of SPARE (cables, connectors, CBs, etc., for future use) + 5% of SPACE (empty connectors, empty CB slots, etc.)

    So we could agree with David Welson partially despite being a good alternative with lower cost. And also, we could agree with you only for "install a panel for only one generator (exclusively)" is not a good idea - spare/space problem not solved. Such alternatives may have higher costs in near future.

    Instead of a "sub panel" or a "generator exclusive panel" maybe a good advice is to install a "parallel main panel #2" with following characteristics:

    - Same dimensions of "existing main panel #1";
    - Same number of spaces of "existing main panel #1";
    - Preferably of the same model as "existing main panel #1", and if not possible, the immediately larger model from the same Manufacturer;
    - Same Ampacity (ampere capacity) of "existing main panel #1" or HIGHER only if the new Generator or new installation demand it;
    - Shift near half (not only one or two) Breakers from "existing main panel #1" to the new "parallel main panel #2", mainly those related or near by to new Generator main trunk - in this way it will have a lot of spare/space in BOTH "existing main panel #1" and "parallel main panel #2" - more than any known Code requirements;
    - No new changes on both Panels will be necessary in near future and still comply to any Code even after many additions - besides parts and spares/spaces are compatible to each other - easier for emergency interventions and maintenance;
    - No need to full shut down of installation for Major Maintenance with 2 Main Panels;

    Hoping this could be of any help, Regards.


    This post was edited by Alex de Moura at March 6, 2019 7:36 PM PST
    • 38 posts
    March 17, 2019 2:45 PM PDT
    Thank you everyone
    • 148 posts
    March 18, 2019 7:56 AM PDT
    Ronnie Rana said:

    NEC recommends 20% of the panel left for future. So a 30 circuit house or commercial space requires a 40 circuit panel, and a 31 circuit space requires a sub panel. Is it really full?  I do not think so?

     

    I have not seen anything in the NEC that states 20% of the panel left for future use.  Could you please show me the section that states this.  I can only find this and article 90 is an introduction and not an enforceable part of the code

     

    90.1(B) Adequacy. This Code contains provisions that are considered
    necessary for safety. Compliance therewith and proper
    maintenance result in an installation that is essentially free
    from hazard but not necessarily efficient, convenient, or
    adequate for good service or future expansion of electrical use.


    Informational Note: Hazards often occur because of overloading
    of wiring systems by methods or usage not in conformity with
    this Code. This occurs because initial wiring did not provide for
    increases in the use of electricity. An initial adequate installation
    and reasonable provisions for system changes provide for future
    increases in the use of electricity.

     

    90.8 Wiring Planning.
    (A) Future Expansion and Convenience. Plans and specifications
    that provide ample space in raceways, spare raceways, and
    additional spaces allow for future increases in electric power
    and communications circuits. Distribution centers located in
    readily accessible locations provide convenience and safety of
    operation.