ProSoundWeb Community

Please login or register.

Login with username, password and session length
Advanced search  

Pages: 1 2 3 [4]   Go Down

Author Topic: Too isolated ground  (Read 17806 times)

Jeff Bankston

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2477
Re: Too isolated ground
« Reply #30 on: April 30, 2014, 09:13:09 pm »

Jeff, I'll take your word for it that your electrical work is top notch-and I assume you put far more effort into your electrical classes than you did English.  I have been an industrial electrician for 16 years-much of it in the same factory.  It can be really humbling when you go back to a job you did 5 years earlier and realize that you did something that you now understand was really, really silly-been there before.  I have been a licensed master electrician and contractor for 12 years(fairly and honestly passed the Experior journeyman and master exams with 94% or better on the first try)-and I still have a lot to learn in the electrical world. (By the way master electrician=one that can draw the plans.)  I always try to find continuing ed classes that not only meet relicensing requirements but also challenge me to learn more.

I suspect that the XO-neutral-bonding question is a matter of local preference.  Iowa has only had a state program for 6 years-as yet there is very little politics on the inspection side of things and they can only enforce the NEC as written.  On a separately derived system-ie transformer supplied panel-the NEC requires the neutral to be bonded to the ground in ONE place.  This can either be the X0 bonded to the ground in the transformer-probably the most  common because it is usually the easiest-or alternatively the neutral buss can be bonded in the panel-if they are not connected in the transformer. My inspector always checks to see that one-and only one of the bonding connections is there.  The NEC does give the AHJ (authority having jurisdiction) final say-so it may be that your inspectors have decided for consistency to require bonding in the transformer and never allowing it in the panel.  There would be advantages to that from an inspection standpoint and future work standpoint when multiple inspectors and electricians are involved.  From a technical and safety standpoint the important thing is that one bonding point does in fact exist.
my post about terminating the ground to building steel or a nearby cooper water pipe was in reference to the I.G. ground only and not the service ground or XO ground. those have to be terminated within 5 feet of where the main water line enters the building, no exceptions allowed. back around the mid 90's there was much argumant amongst electricians and electrical engineers about where the I.G. ground was to be terminated. lots of electricians were terminating it to the common ground buss in the panel. meyself and others had ben installing a small neutral buss(because they come with plastic insulating mounts) and running a "seperate" ground wire to building steel or the xo if we could do it that way or the nearest cold water pipe. some ti's and remodels make it impossible to run a ground back to where the service ground is due to walls etc that would require us to cut holes, core floors, etc. so los angeles buildind safety allowed the I.G. to be terminated elswhere. one reson this was approved was due to service work where an office area didnt have any I.G. recepticals and it is allowed to terminate the I.G. at the restroom copper water pipe. if there is an existing I.G. buss in the panel then thats where the I.G. is terminated. on new buildings and where the I.G. ground has to be run to where the main service ground is thats what is done. If we install a transformer we have to(no exceptions) run the xo ground to the main water pipe within 5 feet of the main water pipe entrance and if walls and floors have to be cut that what is done. i probably made a mess of trying explain this but i can assure you i'm better understood in person........i think ! and my name is Ron Burgundy ?
Logged

Stephen Swaffer

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 2432
Re: Too isolated ground
« Reply #31 on: April 30, 2014, 11:39:00 pm »

Yes. The purpose of a ground is to provide an alternative path for a fault current back to the neutral/ground, etc.

The best way to accomplish this is with one bonding point for neutral/ground/and IG.  Especially since the noise the IG is installed to avoid occurs downstream from this bonding point.  That is also the best way to avoid ground loops.  That said, going to a water pipe might be workable alternative if you can't get back to the main bonding point.  By "might" I simply mean you would have to find out by trial and error if it would work-if that pipe is attached to building steel or someone else has tapped it for a ground it might not be very isolated-just depends.
Logged
Steve Swaffer

ProSoundWeb Community

Re: Too isolated ground
« Reply #31 on: April 30, 2014, 11:39:00 pm »


Pages: 1 2 3 [4]   Go Up
 



Page created in 0.036 seconds with 21 queries.