What would you do & need current readings - Electrician Talk - Professional Electrical Contractors Forum
CLICK HERE AND JOIN OUR COMMUNITY TODAY, IT'S FREE!
Go Back   Electrician Talk - Professional Electrical Contractors Forum > Electrical Forum > General Electrical Discussion


View Poll Results: What would you do
Keep wanting a reason and not drop it. 7 77.78%
Accept it as normal 2 22.22%
Just drop it 0 0%
Voters: 9. You may not vote on this poll

Like Tree33Likes
Reply
 
Thread Tools Display Modes
Old 08-17-2018, 02:21 PM   #1
Senior Member
 
just the cowboy's Avatar
 
Join Date: Sep 2013
Location: Pa
Posts: 1,611
Rewards Points: 412
Default What would you do & need current readings

Sorry long one but I need help!
Two months later and I'm still working on the same problem, I finally got a shutdown scheduled between POCO, union EC that installed service, non-union EC that installed equipment, and myself company electrician. Up to this point it is all finger pointing and no reasons given for my problem.
I'm asking three things in this post:
1. A poll asking "as a electrician what would you do if it was you"
2. Anyone running screw air compressor, and if you could can you take current readings on your ground wire.
3. ANY suggestions on what is wrong.
Let’s start by saying I don't feel right dropping the issue, it goes against everything learned in forty years of electrical work. I was always taught "large amounts of current should not flow on the grounding conductor". Coming off of my air compressors I have three paths for ground current to go.
Grounding wire in conduit, bonded at disconnects and panel.
Conduit itself.
Metal airlines supplying air to plant.
I have three compressors 100HP,150HP,200HP. All three are wired as above. On any of the compressors I can read between 2-5 amps on the grounding wire, not counting what is flowing on the conduit or air lines. This happens on all three and with disconnects open to the other ones so they are not back feeding a problem. I know the current is splitting between conduit and ground wire the way readings change at bonding point.
All cables and motors have been megged and two sets of test equipment have been used to rule out meter problem.
Attached is a drawing showing the ground paths that I know of and some current readings. In the bottom of the panel I have a ground bar, connected to it are.
4-4/0 ground wires going out to pad.
All grounding wires from compressors
Building bonding cable.
A Buss bar that I assume is bonding the neutral bar, no 277 loads used at all on service.
On that buss bar I read 11-20 amps and if I am correct and it is bonding the neutral bar and it is bonded in the xformer that gives me a parallel path between 5 conductors going back to the xformer so maybe 6 x the current or more on a unused connection.
Everyone is saying it MUST be my equipment but I don't buy it and heres why.
1. This equipment runs full load 24/5 and has been running for 9 months.
2. All readings besides the ground current are OK.
3 The big one "IF my equipment is connected to the ground buss that istied to building ground grid how would I get that much current flowing past that point.
So would you
1. Keep wanting a reason and not drop it.
2. Accept it as normal.
3. Just drop it.
Next;
Next the thing, the engineers from the one ECs aid happens all the time with screw compressors. So if anyone can take a current reading on a screw compressor that would be great.
Thank
Cowboy
Attached Files
File Type: pdf groundfault.pdf (76.1 KB, 79 views)
MechanicalDVR and splatz like this.
__________________
A cowboy may get thrown down, but he always gets up and walks forward and don't look back at what thru him.

Last edited by just the cowboy; 08-17-2018 at 02:26 PM.
just the cowboy is offline   Reply With Quote
Join Contractor Talk

Join the #1 Electrician Forum Today - It's Totally Free!

ElectricianTalk.com - Are you a Professional Electrical Contractor? If so we invite you to join our community and see what it has to offer. Our site is specifically designed for you and it's the leading place for electricians to meet online. No homeowners asking DIY questions. Just fellow tradesmen who enjoy talking about their business, their trade, and anything else that comes up. No matter what your specialty is you'll find that ElectricianTalk.com is a great community to join. Best of all it's totally free!

Join ElectricianTalk.com - Click Here JOIN FOR FREE


Warning: The topics covered on this site include activities in which there exists the potential for serious injury or death. ElectricianTalk.com DOES NOT guarantee the accuracy or completeness of any information contained on this site. Always use proper safety precaution and reference reliable outside sources before attempting any construction or remodeling task!

Sponsored Links
Advertisement
 
Old 08-17-2018, 02:38 PM   #2
Modérateur
 
frenchelectrican's Avatar
 
Join Date: Mar 2007
Location: Philippines
Posts: 8,635
Rewards Points: 16,782
Default

Cowboy .,, let me ask you this question .,

Did you have done a quick check at the lighting transfomers?

I know the last screw compressor I work on about a month ago and the one I work on was 125 HP size and set up for 400 volt operation and I end up got about 1 to 1.5 amp the top.

I am not sure if you mention the distance from busbar to the compressor ? how long the run they were if short run then how close the spacing of multi conduits ?

The POCO transformer is set up in Delta - Wye or Wye - Wye ?

I going to find some note about that.,
__________________
Bleu est beau.

Last edited by frenchelectrican; 08-17-2018 at 02:42 PM.
frenchelectrican is offline   Reply With Quote
Old 08-17-2018, 02:45 PM   #3
Senior Member
 
just the cowboy's Avatar
 
Join Date: Sep 2013
Location: Pa
Posts: 1,611
Rewards Points: 412
Default No sub xformers

Quote:
Originally Posted by frenchelectrican View Post
Cowboy .,, let me ask you this question .,

Did you have done a quick check at the lighting transfomers ?
Main is 13,200 - 480/277 xformer from POCO, no other transformers on system. This is one of two services feeding the building, other one has no problems and that is the one that has some 277 but very little, 480 volt lighting in building. Only the three compressors and dryers are on this service
frenchelectrican likes this.
__________________
A cowboy may get thrown down, but he always gets up and walks forward and don't look back at what thru him.
just the cowboy is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 08-17-2018, 03:02 PM   #4
Modérateur
 
frenchelectrican's Avatar
 
Join Date: Mar 2007
Location: Philippines
Posts: 8,635
Rewards Points: 16,782
Default

Quote:
Originally Posted by just the cowboy View Post
Main is 13,200 - 480/277 xformer from POCO, no other transformers on system. This is one of two services feeding the building, other one has no problems and that is the one that has some 277 but very little, 480 volt lighting in building. Only the three compressors and dryers are on this service
Thanks for the reply Cowboy.,

I just hope the POCO transformer is not set up in Wye Wye format as we are aware of ground circulation current show up.

what the POCO did to do their testing their transformer if they did the shutdown and ran the testing?

I am tepting a simple testing but I dont know if you done this or not but if you want to find out where the ground current going ., take a voltmeter and a conductor about 50 meters and take a screw driver and slam in the ground away from POCO source and take the reading from the conductor to the building hot conductor and read the voltage to see how much it drop .

That part it is up to you try that Because I am thinking there some stray current going on.( on ground side )
Southeast Power likes this.
__________________
Bleu est beau.
frenchelectrican is offline   Reply With Quote
Old 08-17-2018, 03:16 PM   #5
Senior Member
 
just the cowboy's Avatar
 
Join Date: Sep 2013
Location: Pa
Posts: 1,611
Rewards Points: 412
Default Yes Wye-Wye

Quote:
Originally Posted by frenchelectrican View Post
Thanks for the reply Cowboy.,

I just hope the POCO transformer is not set up in Wye Wye format as we are aware of ground circulation current show up.

what the POCO did to do their testing their transformer if they did the shutdown and ran the testing?

I am tepting a simple testing but I dont know if you done this or not but if you want to find out where the ground current going ., take a voltmeter and a conductor about 50 meters and take a screw driver and slam in the ground away from POCO source and take the reading from the conductor to the building hot conductor and read the voltage to see how much it drop .

That part it is up to you try that Because I am thinking there some stray current going on.( on ground side )

Yes it is Wye-Wye and a brand new install, but both services are setup the same .
Shutdown is coming, just wanted more data when fingers start pointing.
Already did the wire test for voltage on building, Ran about 150 ' or so to the guard rails in the parking lot that are in driven into the dirt and tested for voltage. 0 VAC .5 VDC.


Just hate that much current on ground.
frenchelectrican likes this.
__________________
A cowboy may get thrown down, but he always gets up and walks forward and don't look back at what thru him.

Last edited by just the cowboy; 08-17-2018 at 03:19 PM.
just the cowboy is offline   Reply With Quote
Old 08-17-2018, 05:01 PM   #6
Registered Member
 
Join Date: Aug 2018
Posts: 169
Rewards Points: 342
Default

Hi Cowboy

can you tell us how many eartherd nuetrals are on site?
SISYPHUS is offline   Reply With Quote
Old 08-18-2018, 10:29 PM   #7
Senior Member
 
DashDingo's Avatar
 
Join Date: Feb 2018
Location: Minnesota
Posts: 108
Rewards Points: 14
Default

Is it possible that it’s being induced?


Sent from my iPhone using Tapatalk
DashDingo is offline   Reply With Quote
Old 08-18-2018, 11:48 PM   #8
Senior Member
 
Join Date: Nov 2008
Location: east coast
Posts: 1,867
Rewards Points: 2,186
Default

What about armature current ? I believe you said the install was 9 months old. May not to be old enough to have bearing problems yet.

LC
__________________
What tools do I need to carry? Use the NEC as your guide keep all your tools ACCESSABLE but keep your everyday tools READILY ACCESSABLE.

Last edited by Lone Crapshooter; 08-19-2018 at 12:46 AM.
Lone Crapshooter is offline   Reply With Quote
Old 08-19-2018, 01:23 AM   #9
Senior Member
 
cuba_pete's Avatar
 
Join Date: Dec 2011
Location: Washington State
Posts: 1,541
Rewards Points: 2,813
Default

The DWG is dated 12.9.94. Are these compressors that old?

What amount of current is on the conduit and the air line?
__________________
Troll in Training
cuba_pete is offline   Reply With Quote
Old 08-19-2018, 01:31 AM   #10
Senior Member
 
Join Date: May 2018
Location: florida
Posts: 1,416
Rewards Points: 1,052
Default

What material are the main air lines....copper?
gpop is online now   Reply With Quote
Old 08-19-2018, 06:51 AM   #11
Registered Member
 
Join Date: Aug 2018
Posts: 169
Rewards Points: 342
Default

Quote:
Originally Posted by just the cowboy View Post
Yes it is Wye-Wye and a brand new install, but both services are setup the same .
Shutdown is coming, just wanted more data when fingers start pointing.
Already did the wire test for voltage on building, Ran about 150 ' or so to the guard rails in the parking lot that are in driven into the dirt and tested for voltage. 0 VAC .5 VDC.


Just hate that much current on ground.
I would try frenchelectrican's simple test , while shutting down each service
frenchelectrican likes this.
SISYPHUS is offline   Reply With Quote
Old 08-19-2018, 08:56 AM   #12
86 45 20
 
Southeast Power's Avatar
 
Join Date: Jan 2009
Location: Florida
Posts: 17,745
Rewards Points: 8,166
Default

For me, it seems like quite a bit of resources being invested into a problem that might not be a problem.
I'm not sure there is going to be a smoking gun here with the EC stating this is a normal condition.
There could be all kinds of interesting science happening with bringing in ambient air, compressing it into several atmospheres difference and drying it all with a constantly rotating machine.

I would speak directly with the supplier and get answers from the right end of the horse.
Southeast Power is online now   Reply With Quote
Old 08-19-2018, 09:15 AM   #13
Registered Member
 
Join Date: Aug 2018
Posts: 169
Rewards Points: 342
Default

Guardrails that run right along side poles that ground XO probably all voted for Kirchoff
wildleg likes this.
SISYPHUS is offline   Reply With Quote
Old 08-19-2018, 10:04 AM   #14
Senior Member
 
gnuuser's Avatar
 
Join Date: Jan 2013
Location: nw. Pa.
Posts: 1,761
Rewards Points: 1,528
Default

another thing to consider is static electricity If you have air movement across metal and plastics it will produce static charges.
(we had this issue with some plc controlled air operated equipment)
static buildup would cause errors in operation and sometimes burn out a cpu module)
we ended up bonding the airlines and conduits throughout the plant and solved that issue
compressors and air driers are noted for generating static electricity!
so its just a thought to consider.
frenchelectrican and JRaef like this.
__________________
ive been shocked so many times that my eyes light up and i fart lightning bolts.

Miracle (mere-ack-ull):the aspirations of the indigent, The expectation of the indolent, and the inspiration of the ignorant.
gnuuser is offline   Reply With Quote
The Following User Says Thank You to gnuuser For This Useful Post:
Southeast Power (08-19-2018)
Old 08-19-2018, 11:55 AM   #15
Senior Member
 
Going_Commando's Avatar
 
Join Date: Oct 2011
Location: New Hampshah
Posts: 6,048
Rewards Points: 1,486
Default

Weird. Out of curiosity what made you check current on grounds to begin with?
__________________
"I bet you smell like cigarettes and felonies." -HackWork
Going_Commando is offline   Reply With Quote
Old 08-19-2018, 12:00 PM   #16
Conservitum Americum
 
LARMGUY's Avatar
 
Join Date: Aug 2010
Location: Oklahoma
Posts: 8,063
Rewards Points: 574
Default

Doesn't the NEC state grounds cannot serve as a current carrying conductor therefore you have to investigate and solve?

As for static electricity, voltage can be created but the 2 Amp measurement throws me off.

https://www.ecmweb.com/ops-amp-maint...ground-current


Good article on ground fault current.
__________________
Cowboy words of wisdom.
There are three types of men, those that learn by readin, those that learn by watchin, and those that have to pee on the electric fence for themselves.

,
LARMGUY is offline   Reply With Quote
Old 08-19-2018, 12:10 PM   #17
animal lover /rat bastard
 
wildleg's Avatar
 
Join Date: Apr 2009
Location: somewhere in FL
Posts: 13,547
Rewards Points: 1,038
Default

on the 1500 amp panel, what is the total current on the outbound ground ?
(is it additive ? ie, does it equal the sum of the current on the 3 compressors or does it cancel ?)
__________________
this message was sent from a dental floss farm using ZappaTalk and a pair of zirconium encrusted tweasers
wildleg is offline   Reply With Quote
Old 08-19-2018, 02:20 PM   #18
Senile Member
 
macmikeman's Avatar
 
Join Date: Jan 2007
Location: Honolulu
Posts: 26,973
Rewards Points: 16,305
Default

Start looking for voltage potential differences between equipment ground at machine and the building service. If none are to be found, take the battery out of your digital current probe and hit it with a hammer. Maybe hit the amprobe as well.
__________________
Thought for the Day: President Trump is the first sitting U.S. president to EVER step foot in North Korea... Obama got a Nobel Peace Prize for being black.
macmikeman is offline   Reply With Quote
Old 08-19-2018, 02:21 PM   #19
Senior Member
 
sbrn33's Avatar
 
Join Date: Mar 2007
Location: middle america
Posts: 11,445
Rewards Points: 3,290
Default

Honestly, what made you amp out the ground anyway? Was there trouble or what?
sbrn33 is offline   Reply With Quote
Old 08-19-2018, 03:32 PM   #20
Cow
Senior Member
 
Join Date: Jan 2008
Location: Eastern Oregon
Posts: 2,882
Rewards Points: 4,600
Default

The simplest solution is to pay Brian John to come out and look at it.
Cow is online now   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
VFD overcurrent Protection ceilingwalker NEC Code Forum 49 07-14-2018 01:07 PM
Current on ground big time. just the cowboy General Electrical Discussion 27 05-31-2018 02:04 PM
Ground Current brian john General Electrical Discussion 13 05-22-2018 10:46 AM
Leakage current collector Aegis Canadian Electrical Forum 4 04-30-2016 01:55 PM


All times are GMT -4. The time now is 07:49 PM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.1
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Our Pro Sites Network
ContractorTalk.com | DrywallTalk.com | HVACSite.com | PaintTalk.com | PlumbingZone.com | RoofingTalk.com