586,124 active members*
3,144 visitors online*
Register for free
Login
Results 1 to 5 of 5
  1. #1
    Join Date
    Apr 2014
    Posts
    345

    Help Current through ground

    I just finished my cnc control box and hooked it up to power with the geckos disconnected ( mostly to test fans) and I get a slight shock when I ground myself and touch the box. All the grounds lead to one common point and out through the ac power. The one common point is the back plate. So far I tested resistance from all the hot leads and got nothing saying they were leaking. So is it possible that the ground isn't going out the ac? Or is the power suply putting out extra currents or something?
    Click image for larger version. 

Name:	ImageUploadedByTapatalk1428344244.239508.jpg 
Views:	0 
Size:	192.5 KB 
ID:	275748

  2. #2
    Join Date
    Feb 2007
    Posts
    711

    Re: Help Current through ground

    that back plate might be insulated from the case.
    still, there should be no voltage present at the case, unless something is leaking.
    Are those fans AC? cheap chinese ones?

  3. #3
    Join Date
    Dec 2003
    Posts
    24221

    Re: Help Current through ground

    Do you have the service ground properly grounded to the enclosure?
    Often if there is paint on the threads etc, it can cause a problem.
    Measure from live conductor to the back panel to see if you at least get 120/240 depending on where you are.
    Al.
    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.

  4. #4
    Join Date
    Apr 2014
    Posts
    345

    Re: Help Current through ground

    I determined the problem. There was no grounding at my service outlet. The wire was not connected properly. All grounds are connected to the backboard.
    I was worried about this excess current because my CPU is on the lid of that box.

    Btw those are ac fans and they are old prob from the 80's from a laser company that a friend of mine used to own. One says commonwealth brand don't remember the other.

  5. #5
    Join Date
    May 2014
    Posts
    182

    Re: Help Current through ground

    As another precaution, a lot of unregulated power supplies will have a slow blow fuse connected on the output of the positive lead.

    I'm not sure if this is appropriate for your situation, but it I guess it helps the current from leaking to the frame.

Similar Threads

  1. Are stepper motors rated peak current or RMS current?
    By tauntdesigns in forum Stepper Motors / Drives
    Replies: 10
    Last Post: 07-25-2014, 04:32 AM
  2. Low Current interface, High Current Motor?
    By Clackvalve in forum CNC Machine Related Electronics
    Replies: 15
    Last Post: 05-13-2010, 06:42 PM
  3. Frame ground vs. Electrical ground.
    By polaraligned in forum CNC (Mill / Lathe) Control Software (NC)
    Replies: 2
    Last Post: 11-24-2008, 11:21 PM
  4. To Ground or not to Ground That is the question!
    By Mr.Chips in forum DIY CNC Router Table Machines
    Replies: 1
    Last Post: 03-16-2008, 09:10 PM
  5. Motor supply ground vs Logic ground?
    By Gashmore in forum CNC Machine Related Electronics
    Replies: 11
    Last Post: 06-07-2005, 11:21 PM

Tags for this Thread

Posting Permissions

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