(206) 949-5683, Top Rated Plumber, Seattle
Results 1 to 7 of 7

Thread: Questions about sub panel and 30A circuit

  1. #1
    DIY Junior Member mcsincnj's Avatar
    Join Date
    Jul 2013
    Location
    Greenville SC
    Posts
    3

    Default Questions about sub panel and 30A circuit

    My post has three questions. This project is for a sub panel located in my workshop. I have been working on this for about 6 months and now see a couple of issues I didn't identify in the beginning. It is a time consuming project that I can finally see the light at the end of the tunnel!
    I have attached the pictures for ease of interpretation.
    Q: I have a main lug configuration, which according to the diagram below says it should be in the same building; can I use this sub-panel in an out building or am I wrong right out of the box?
    Name:  Lug Box.jpg
Views: 658
Size:  62.0 KB Name:  Main2Main-lug.jpg
Views: 1914
Size:  33.5 KB

    Q: I also saw that MY bonding rod IS connected, and should be disconnected for this application? I have a grounding rod,but the diagram I saw shows not to apply this in this configuration? Will it hurt to add the rod or is it redundant.

    My wire to feed from my main breaker box is type TC-ER THHN/THUN CDRS DIRECT BURY (#6-3C THHN-PVC Tray Cable with Ground) on a 60A breaker.
    Name:  Wire.jpg
Views: 575
Size:  49.9 KB
    Breaker in House --->Name:  Breakers.jpg
Views: 505
Size:  46.4 KB

    Q: The second part of my post is that I have a sander that is labeled 110v/28a.
    Name:  Sander.jpg
Views: 491
Size:  57.7 KB
    I want to add a circuit dedicated to this machine. The machine is 22 years old and I don't know where the wiring diagram could be, so I don't want to convert it to 220v.
    So, I am looking for a 30a outlet & I have not looked for the 30a single pole breaker (if there is such), but all I see is for RV applications.
    I assume that I will need to replace the plug on the machine to match the outlet, but am not sure what to use.

    I need some additional help with this.

    Thank you in advance for your help.

  2. #2
    Licensed Electrical Contractor Speedy Petey's Avatar
    Join Date
    Jun 2007
    Location
    NY State, USA
    Posts
    975

    Default

    You do need a main disconnect, and a ground rod, and to isolate the neutral bar, and to add a ground bar, at this remote sub-panel.
    I would replace that panel with a typical 100A main-breaker panel. Much easier and you will not lose the two breaker spaces by using a backfeed breaker. If you do backfeed the breaker must have a retention device installed.



    If I were you I'd try to re-wire the machine for 240V, NO question. If you insist on 120V then you need 10/2 cable and a 5-30R receptacle and 5-30P plug for the cord. That is assuming the cord is already the correct size.
    If it is already wired for 120V why would you need to change it?
    Last edited by Speedy Petey; 07-13-2013 at 04:46 PM.

  3. #3
    DIY scratch-pad engineer leejosepho's Avatar
    Join Date
    Nov 2006
    Location
    200 miles south of Little Rock
    Posts
    2,474

    Default

    10/2 cable and a 6-30R receptacle and 6-30P plug for the cord.
    That is what I did for a 40-year-old welder calling for a 30A fuse back in the day when 12-2 was considered heavy enough to handle that, then I found a short pigtail cord with two regular 120V outlets on the end so I can plug regular stuff in at that 6-30R outlet while the welder is disconnected. But unless your sander has additional 120V circuitry (a light or whatever) that might complicate things -- a double-pole 30A switch should not be too difficult to find -- I would find a motor shop where someone can easily tell you how to properly wire and run that motor with 240V.
    Last edited by leejosepho; 07-13-2013 at 04:28 PM.
    "Great minds discuss ideas, average minds discuss events and small minds discuss people." --Eleanor Roosevelt

  4. #4
    Licensed Electrical Contractor Speedy Petey's Avatar
    Join Date
    Jun 2007
    Location
    NY State, USA
    Posts
    975

    Default

    Sorry. I edited from 6-30 to 5-30.

    6-30R is 240V/30A
    5-30R is 120V/30A

  5. #5
    DIY Senior Member Homeownerinburb's Avatar
    Join Date
    Jan 2012
    Location
    Los Angeles, CA USA
    Posts
    505

    Default

    Pete's got you covered.

    The panel he recommends is not going to cost you much. Just go with the right equipment.

  6. #6
    DIY Junior Member mcsincnj's Avatar
    Join Date
    Jul 2013
    Location
    Greenville SC
    Posts
    3

    Default

    Thanks for the diagram...
    Last edited by mcsincnj; 07-14-2013 at 02:42 PM. Reason: Moved to proper location

  7. #7
    DIY Junior Member mcsincnj's Avatar
    Join Date
    Jul 2013
    Location
    Greenville SC
    Posts
    3

    Default

    Quote Originally Posted by Speedy Petey View Post
    You do need a main disconnect, and a ground rod, and to isolate the neutral bar, and to add a ground bar, at this remote sub-panel.
    I would replace that panel with a typical 100A main-breaker panel. Much easier and you will not lose the two breaker spaces by using a backfeed breaker. If you do backfeed the breaker must have a retention device installed.



    If I were you I'd try to re-wire the machine for 240V, NO question. If you insist on 120V then you need 10/2 cable and a 5-30R receptacle and 5-30P plug for the cord. That is assuming the cord is already the correct size.
    If it is already wired for 120V why would you need to change it?



    Thanks for the diagram... One picture is worth 1000 words. The breaker box in the house currently has the neutral and grounding wires to the same lugs, not separate as shown, is that a problem? I have looked all over and don't see a grounding rod outside or inside. It may be in the wall?

    So you are saying that I should have 60A (breaker) feed from the house box to a 60A disconnect (main), ground isolated to gr. rod, etc.

    As for the sander, I will open the wiring plate and hopefully, there is a lug labeled 240v with nothing attached before deciding what I direction to take. BTW, what book can I find your diagram?

    Thanks for the assistance!
    Last edited by mcsincnj; 07-14-2013 at 03:35 PM.

Similar Threads

  1. Radiant Supply Panel Questions
    By Leaky1 in forum HVAC Heating & Cooling
    Replies: 4
    Last Post: 12-26-2011, 09:06 AM
  2. Old Existing G.E. Circuit Breaker Panel
    By Ford2001 in forum Electrical Forum discussion & Blog
    Replies: 2
    Last Post: 11-25-2009, 01:58 PM
  3. Main Circuit Breaker Panel Humms
    By edstevn in forum Electrical Forum discussion & Blog
    Replies: 2
    Last Post: 12-02-2008, 07:29 AM
  4. New circuit added via rear knockout in service panel?
    By roegs in forum Electrical Forum discussion & Blog
    Replies: 5
    Last Post: 08-02-2008, 04:26 AM
  5. 100A Main Panel…..100A Branch Circuit?
    By lahabra in forum Electrical Forum discussion & Blog
    Replies: 5
    Last Post: 01-01-2008, 10:10 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •