Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Electrical

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 02-19-2009, 08:50 AM   #16
DIY'er
 
jamiedolan's Avatar
 
Join Date: Sep 2008
Location: Neenah, Wisconsin, USA
Posts: 2,032
Blog Entries: 2
Share |
Default

Ground connection / Bonding in EMT


Quote:
Originally Posted by Stubbie View Post
Jamie

Don't take me too seriously just poling some fun. Your doing fine.


2/0 200 amp service entrance conductor requires a grounding electrode conductor to the water pipe of #4 copper. NEC table 250.66

Your not sizing grounding electrode conductor....your sizing...equipment grounding conductor which is sized to the protecting circuit breaker. A #6 copper will suffice for a 200 amp breaker protecting a feeder. Use this table below...NEC table 250.122



Or go here and use the calculators


http://www.electrician2.com/calculators/elcal.html
Yep, at my parents with 200A service, We bonded the gas and water pipe with 4awg. The first night after we had that short, and there was an electrical out, he insisted on running 4awg to the ground rods, even thought I told him 6awg was all that was required.

Now that I see your chart, I remember why I was going to pull the 6 vs 10, I don't have 8, and if I was going to run the sub at 70A, then I need the larger ground. I have to double check again, but I think my CH breakers, in both panels are rated with 90degree terminals, so they would support up to 75a. I suppose it is a lot of extra effort for just 10 more A of service at my sub panel. Which I likely won't really need.

Thanks for the chart and other information,
Jamie

__________________
Jamie Dolan - Neenah, WI
Jamie Dolan Paw Dogs
Need Help Uploading Photos? Click here.
jamiedolan is offline   Reply With Quote
Old 02-19-2009, 08:52 AM   #17
DIY'er
 
jamiedolan's Avatar
 
Join Date: Sep 2008
Location: Neenah, Wisconsin, USA
Posts: 2,032
Blog Entries: 2
Default

Ground connection / Bonding in EMT


Quote:
Originally Posted by AllanJ View Post
Out of curiosity, why would the grounding conductor need to be insulated?
I believe It's only required on pools per 680. But now sure why, perhaps they think it is more resistant to corrosion with insulation on it? Or they want the ground to be isolated for some reason?
Jamie
__________________
Jamie Dolan - Neenah, WI
Jamie Dolan Paw Dogs
Need Help Uploading Photos? Click here.
jamiedolan is offline   Reply With Quote
Old 02-19-2009, 04:57 PM   #18
Electrician
 
Join Date: Aug 2007
Location: Connecticut, Litchfield
Posts: 2,015
Default

Ground connection / Bonding in EMT


Quote:
Originally Posted by InPhase277 View Post
It would be a shame that you do all that over-the-top electrical work in the place just to go and bastardize it by using the EMT as your ground.

Here is a good article for ya...! http://www.steelconduit.org/pdf/groundingpart1.PDF

Also, anyone IMO that pulls a EGC in EMT just likes that warm fuzzy feeling inside when the do it, but dont really know why they do it.
chris75 is offline   Reply With Quote
Old 02-19-2009, 05:41 PM   #19
My License Ain't 4 Sale..
 
Join Date: Feb 2008
Location: Atlanta, Ga/Hamilton, Al
Posts: 1,813
Default

Ground connection / Bonding in EMT


Quote:
Originally Posted by chris75 View Post
Here is a good article for ya...! http://www.steelconduit.org/pdf/groundingpart1.PDF

Also, anyone IMO that pulls a EGC in EMT just likes that warm fuzzy feeling inside when the do it, but dont really know why they do it.
Wrong. I know full well why I do it. IMO, people opposed to pulling an EGC in conduit are usually romex slingers. I have seen way too many loose pipe connections and burnt locknuts to just rely on the pipe.
InPhase277 is offline   Reply With Quote
Old 02-19-2009, 05:49 PM   #20
UAW SKILLED TRADES
 
Stubbie's Avatar
 
Join Date: Jan 2007
Location: Kansas
Posts: 4,876
Default

Ground connection / Bonding in EMT


I'm gonna agree with Chris on this one especially residential there just isn't any need for it. Make up the emt correctly and it is about as good a ground as you can get for carrying fault current.


While I worked at Ford we never pulled one, but around 2001 they had an incident at the Rouge where a Hi low driver was electrocuted by a 3 phase 480 ground fault. Some maintenance guy dropped out of a junction box of an emt run in a high bay with a switch loop and stuck the motor controller at normal switch level so they could turn a fan on and off. They did not guard it. A hi-low hit the emt breaking it apart at the switch. Then about a week later another hi low backed into the switch and somehow got zapped. They blamed it on the broken fault path from the earlier damage. Anyway after that they mandated an equipment ground be ran with emt runs. Silly really the whole thing was just an overreaction because the switch should have never been where it was installed and without guard. Nothing like having 480 volt motor control where every worker could walk up to it and operate it to their pleasure.
__________________
" One nice thing about the NEC articles ... you have lots of choices"

Stubbie
Stubbie is offline   Reply With Quote
Old 02-19-2009, 06:36 PM   #21
My License Ain't 4 Sale..
 
Join Date: Feb 2008
Location: Atlanta, Ga/Hamilton, Al
Posts: 1,813
Default

Ground connection / Bonding in EMT


Quote:
Originally Posted by Stubbie View Post
I'm gonna agree with Chris on this one especially residential there just isn't any need for it.
I'm not disagreeing with either of you, but that doesn't change my stance on installing an EGC. Your next statement makes my point precisely.


Quote:
Make up the emt correctly and it is about as good a ground as you can get for carrying fault current.
I have seen EMT installed where fittings were never tightened, and I've seen it where normal use over the years has jogged a locknut loose. I agree that EMT is an excellent ground, and, as evidenced by the report that Chris posted, in fact ends up carrying the majority of the fault current even when a separate ground is installed. But, in my opinion, relying on the conduit as a fault path is analogous to relying on the neutral as the ground in a range circuit: most times it will be OK, but every now and then somebody gets killed.

There is nothing wrong with going beyond the bare minimum that's allowed. Aside from the additional cost, there are no negatives to installing an EGC, while there are several potential problems when not installing one.

Last edited by InPhase277; 02-19-2009 at 06:40 PM.
InPhase277 is offline   Reply With Quote
Old 02-19-2009, 09:21 PM   #22
DIY'er
 
jamiedolan's Avatar
 
Join Date: Sep 2008
Location: Neenah, Wisconsin, USA
Posts: 2,032
Blog Entries: 2
Default

Ground connection / Bonding in EMT


Thanks guys. This has been an interesting conversation. I appreciate the info.
Jamie
__________________
Jamie Dolan - Neenah, WI
Jamie Dolan Paw Dogs
Need Help Uploading Photos? Click here.
jamiedolan is offline   Reply With Quote
Old 02-19-2009, 10:42 PM   #23
Electrician
 
Join Date: Aug 2007
Location: Connecticut, Litchfield
Posts: 2,015
Default

Ground connection / Bonding in EMT


Quote:
Originally Posted by InPhase277 View Post
Wrong. I know full well why I do it. IMO, people opposed to pulling an EGC in conduit are usually romex slingers. I have seen way too many loose pipe connections and burnt locknuts to just rely on the pipe.
Thats nice, but one loose grounding splice is the same thing as a loose emt connector. So your point is moot point. Just my opinion of course.

See where I'm going with this? A loose EMT connector or coupling is as simple as a bad grounding connector at a box or at the panel, a grounding conductor is USELESS if its not terminated properly.

Last edited by chris75; 02-19-2009 at 10:47 PM.
chris75 is offline   Reply With Quote
Old 02-19-2009, 10:54 PM   #24
Electrician
 
Join Date: Aug 2007
Location: Connecticut, Litchfield
Posts: 2,015
Default

Ground connection / Bonding in EMT


Quote:
Originally Posted by InPhase277 View Post
Wrong. I know full well why I do it. IMO, people opposed to pulling an EGC in conduit are usually romex slingers. I have seen way too many loose pipe connections and burnt locknuts to just rely on the pipe.

So you admit to the warm fuzzy feeling you get when you pull a EGC in EMT?
chris75 is offline   Reply With Quote
Old 02-20-2009, 07:14 AM   #25
My License Ain't 4 Sale..
 
Join Date: Feb 2008
Location: Atlanta, Ga/Hamilton, Al
Posts: 1,813
Default

Ground connection / Bonding in EMT


Quote:
Originally Posted by chris75 View Post
So you admit to the warm fuzzy feeling you get when you pull a EGC in EMT?
Absolutely. From my toes to my nose...
InPhase277 is offline   Reply With Quote
Old 02-20-2009, 07:27 AM   #26
My License Ain't 4 Sale..
 
Join Date: Feb 2008
Location: Atlanta, Ga/Hamilton, Al
Posts: 1,813
Default

Ground connection / Bonding in EMT


Quote:
Originally Posted by chris75 View Post
Thats nice, but one loose grounding splice is the same thing as a loose emt connector. So your point is moot point. Just my opinion of course.

See where I'm going with this? A loose EMT connector or coupling is as simple as a bad grounding connector at a box or at the panel, a grounding conductor is USELESS if its not terminated properly.
Well of course. But statistically what's more likely? Someone doesn't tighten a set screw, or someone leaves a ground wire hanging? Wires tend to be terminated one at a time, and therefore likely to be terminated properly. Conduit fittings are easier to miss for some reason. I've seen it a million times. Sure I've seen loose ground wires, but not nearly as many. I was walking through Wal-Mart a few months back and saw a receptacle on a column where it looked like the set screw was out a little far. I pulled a dime out and turned it (yeah, I do things like that). It not only was loose, it had never been tightened. Never saw a screwdriver.

Look, you want to install conduit without a ground? Knock yourself out. Nothing wrong with it for a pro. If I give a DIY who is using conduit advice, I feel better him using an EGC. On my jobs I use an EGC. It takes no more time and costs ME no more money. The customer absorbs the cost and gets a better-than-minimal install.
InPhase277 is offline   Reply With Quote
Old 02-20-2009, 07:34 AM   #27
Member
 
Join Date: Jul 2008
Location: Iowa
Posts: 1,543
Default

Ground connection / Bonding in EMT


Quote:
Originally Posted by InPhase277 View Post
gets a better-than-minimal install.

Look at the termite's sig.

edit: looks like its not there anymore


Anyways, I always like better than minimum installs.

Last edited by rgsgww; 02-20-2009 at 07:36 AM.
rgsgww is offline   Reply With Quote
Old 02-20-2009, 10:05 AM   #28
UAW SKILLED TRADES
 
Stubbie's Avatar
 
Join Date: Jan 2007
Location: Kansas
Posts: 4,876
Default

Ground connection / Bonding in EMT


Who's gonna get the last word.....

I see both sides of the argument to some degree. I've seen first timers at the DIY level just spin on the locknuts and call it good not understanding the critical aspect of it being tight. But generally I think it is because they have no intention of using it for ground because they don't know that it can be equipment ground. They pull an egc. I've even seen them pull an egc for every circuit in the conduit.

So I think Inphase has a valid point on singling out whether a pro is installing the emt or some homeowner who really hasn't ever worked with it nor do they understand some of the little things that get it made up correctly. Granted it is'nt real difficult...the locknut being the biggest weak link in my opinion. I actully see alot of homeowners using emt not having a clue how to cut it and then ream it out. A lot of these people use a soft copper tubing cutter that pushes a razor edge to the inside of the pipe...and then don't know they are supposed to ream it.

So there is a lot to be said about who is installing the emt and do they lnow how to work with it, especially using it for ground.

I've been experimenting with using a unibit in my cordless on 1/2 and 3/4 emt to ream it. I think it works well , so give it a try and give me some feed back on what you think.

I also just purchsed the greenlee cutter that looks like a tubing cutter only for emt....I like it. but I won't leave my hacksaw at home either. And in a pinch I've been known to ream with my cresent....

But I do agree with Inphase it has a lot to do with who installs it. Cause Murphy is always out there watching.
__________________
" One nice thing about the NEC articles ... you have lots of choices"

Stubbie
Stubbie is offline   Reply With Quote
Old 02-20-2009, 10:16 AM   #29
DIY'er
 
jamiedolan's Avatar
 
Join Date: Sep 2008
Location: Neenah, Wisconsin, USA
Posts: 2,032
Blog Entries: 2
Default

Ground connection / Bonding in EMT


Quote:
Originally Posted by Stubbie View Post
Who's gonna get the last word.....

I see both sides of the argument to some degree. I've seen first timers at the DIY level just spin on the locknuts and call it good not understanding the critical aspect of it being tight. But generally I think it is because they have no intention of using it for ground because they don't know that it can be equipment ground. They pull an egc. I've even seen them pull an egc for every circuit in the conduit.

So I think Inphase has a valid point on singling out whether a pro is installing the emt or some homeowner who really hasn't ever worked with it nor do they understand some of the little things that get it made up correctly. Granted it is'nt real difficult...the locknut being the biggest weak link in my opinion. I actully see alot of homeowners using emt not having a clue how to cut it and then ream it out. A lot of these people use a soft copper tubing cutter that pushes a razor edge to the inside of the pipe...and then don't know they are supposed to ream it.

So there is a lot to be said about who is installing the emt and do they lnow how to work with it, especially using it for ground.

I've been experimenting with using a unibit in my cordless on 1/2 and 3/4 emt to ream it. I think it works well , so give it a try and give me some feed back on what you think.

I also just purchsed the greenlee cutter that looks like a tubing cutter only for emt....I like it. but I won't leave my hacksaw at home either. And in a pinch I've been known to ream with my cresent....

But I do agree with Inphase it has a lot to do with who installs it. Cause Murphy is always out there watching.
I was guilty of trying the copper pipe cutter, but realized it was wrong because it took me forever to ream and file it down.

I tried the greenlee, but it didn't seem to cut that well. Now my dad uses a big disk grinder with a cut off disk. It is extremely fast, and makes very clean cuts. Then he uses the deburr tool just to be safe. I ran a ground in all of his emt, except 2 runs to high up lights. His emt is so secure, I could do pull ups on it. . I am positive that EMT is just as good and secure as any professional job. You guys have seen enough photos of my work to know that I am not doing a half way job on anything. But I still ran the grounds just because I felt like it was a good pratice, but I did look at it a number of times, and go, hmm,what really is the point here, the house is going to have to fall down before this conduit comes apart. Anyway I agree about it being a good pratice and will continue to run a ground, even if it is a bit above and beyond.
Jamie
__________________
Jamie Dolan - Neenah, WI
Jamie Dolan Paw Dogs
Need Help Uploading Photos? Click here.

Last edited by jamiedolan; 02-20-2009 at 10:19 AM.
jamiedolan is offline   Reply With Quote
Old 02-16-2013, 10:43 AM   #30
Member
 
Join Date: Nov 2007
Location: Nashua, NH, USA
Posts: 6,864
Default

Ground connection / Bonding in EMT


Wow! Ten minutes on Google and still haven't found a definitive authoritative Table 250.66. One narrative I found gives #6 copper grounding electrode conductor for service up to 100 amps, #4 GEC up to 150 amps and #3 (use #2 if needed) up to 200 amps. One table goes like this: #2 or smaller service entrance uses #8 GEC, up to 1/0 use #6, up to 3/0 use #4. But I'm skeptical here because #2 is used for 100 amps and other sources say #8 GEC is too small.

Wow! Meant to reply to another thread but Google dredged up this thread and I added to it by mistake!

One electrode needs a GEC non-stop to the panel. Ground rods need a maximum of #6 copper GEC but if another electrode (e.g. water pipe) needs a fatter GEC then that one must run non-stop to the panel and, if desired, other GECs may be clamped onto that.

__________________
Stop wasting time re-adjusting the pattern. Have several lawn sprinklers, one for each pattern.

Last edited by AllanJ; 02-16-2013 at 10:59 AM.
AllanJ is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
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
Bonding Ground in Conduit jamiedolan Electrical 5 01-26-2010 10:14 PM
This doesnt seem right. JoulesWinfield Electrical 27 07-26-2009 07:40 PM
Bonding & Ground Rod Question bradsguns Electrical 3 06-13-2008 12:55 PM
Bonding Ground and Neutral matrix733 Electrical 11 11-28-2007 06:22 PM
Subpanel feeder questions Silhanek Electrical 4 03-22-2007 06:30 PM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.