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 11-14-2012, 09:19 PM   #16
E2 Electrician
 
stickboy1375's Avatar
 
Join Date: Apr 2012
Location: Litchfield, CT
Posts: 5,089
Rewards Points: 0
Share |
Default

ground rod


Quote:
Originally Posted by mterry View Post
But it does seek the much lower resistance of a copper grounding system than, say, the impedance of human, wood, brick, glass, rubber, plastic, right?
Has nothing to do with that...Thats not the intent of the grounding electrode system. Don't over think it...

stickboy1375 is offline   Reply With Quote
Old 11-14-2012, 09:29 PM   #17
Member
 
Join Date: Feb 2010
Location: Oklahoma
Posts: 978
Rewards Points: 0
Default

ground rod


Quote:
Originally Posted by mterry
But it does seek the much lower resistance of a copper grounding system than, say, the impedance of human, wood, brick, glass, rubber, plastic, right?
Bonding vs grounding. Two separate principles.
jlmran is offline   Reply With Quote
The Following User Says Thank You to jlmran For This Useful Post:
stickboy1375 (11-14-2012)
Old 11-14-2012, 09:30 PM   #18
E2 Electrician
 
stickboy1375's Avatar
 
Join Date: Apr 2012
Location: Litchfield, CT
Posts: 5,089
Rewards Points: 0
Default

ground rod


Quote:
Originally Posted by jlmran View Post
Bonding vs grounding. Two separate principles.
Yeah, also the hardest part of the NEC to grasp for some guys...
stickboy1375 is offline   Reply With Quote
Old 11-14-2012, 09:32 PM   #19
Member
 
Join Date: Feb 2010
Location: Oklahoma
Posts: 978
Rewards Points: 0
Default

ground rod


Diychatroom needs a sticky on bonding vs. grounding. Do the admins pay? I'll write one for a payment.
jlmran is offline   Reply With Quote
Old 11-14-2012, 09:33 PM   #20
Electrical Contractor
 
jbfan's Avatar
 
Join Date: Jun 2004
Location: Newnan GA
Posts: 5,788
Rewards Points: 8
Default

ground rod


Quote:
Originally Posted by jlmran View Post
Diychatroom needs a sticky on bonding vs. grounding. Do the admins pay? I'll write one for a payment.
Free postings for a week!
__________________
Yes I am a Pirate, 200 years too late. "Jimmy Buffett"
jbfan is offline   Reply With Quote
The Following 2 Users Say Thank You to jbfan For This Useful Post:
electures (11-15-2012), stickboy1375 (11-14-2012)
Old 11-14-2012, 09:34 PM   #21
JOATMON
 
ddawg16's Avatar
 
Join Date: Aug 2011
Location: S. California
Posts: 7,246
Rewards Points: 12
Default

ground rod


Earth Grounds fall into the area of FM.....(F'ing Magic).

When doing just one ground rod....if one could insure that the ground moisture always stayed the same....and all ground dirt was the same....etc...etc...then sure, one rod would be fine.

Many many years ago when I was in the AF doing combat HF and microwave communications.....a good ground was crucial to an HF antenna having good propogation....so we acutually used a megger to measure the ground resistance.....if it was not low enough....we got the water truck over to our area of the LZ and we would wet down the ground.

As hard as it migh be to believe.....grounding is one of those technologies that is still evolving....
__________________
"The dream is free but the hustle is sold separately."

My 2-Story Addition Build in Progress Link ... My Garage Build Link and My Jeep Build Link
ddawg16 is online now   Reply With Quote
Old 11-14-2012, 09:36 PM   #22
Member
 
Join Date: Feb 2010
Location: Oklahoma
Posts: 978
Rewards Points: 0
Default

ground rod


Quote:
Originally Posted by jbfan

Free postings for a week!
I don't know if any of my posts have been whacked by a mod. Maybe...

Remember the guy who posted the bird using a different IP address? He was mad.
jlmran is offline   Reply With Quote
Old 11-14-2012, 09:37 PM   #23
Member
 
Join Date: Feb 2010
Location: Oklahoma
Posts: 978
Rewards Points: 0
Default

ground rod


Quote:
Originally Posted by ddawg16
Earth Grounds fall into the area of FM.....(F'ing Magic).

When doing just one ground rod....if one could insure that the ground moisture always stayed the same....and all ground dirt was the same....etc...etc...then sure, one rod would be fine.

Many many years ago when I was in the AF doing combat HF and microwave communications.....a good ground was crucial to an HF antenna having good propogation....so we acutually used a megger to measure the ground resistance.....if it was not low enough....we got the water truck over to our area of the LZ and we would wet down the ground.

As hard as it migh be to believe.....grounding is one of those technologies that is still evolving....
An absolutely totally different use of the earth.
jlmran is offline   Reply With Quote
Old 11-15-2012, 07:25 AM   #24
Member
 
Join Date: Nov 2007
Location: Nashua, NH, USA
Posts: 6,946
Rewards Points: 0
Default

ground rod


The code regarding ground rods is somewhat arbitrary. You need to achieve an impedance of 25 ohms or less between grounding electrode system and the earth, or drive two 8 foot ground rods, whichever comes first.

The simple meaning of a bond is an intended and essentially resistance free electrical connection, with the provision that, if A is bonded to B and B is bonded to C then A is bonded to C. (An unintended electrical connection is called a fault.)

Seems like we don't have enough words in the English language to describe things. Suppose we have an electric drill with the usual 3 prong plug in the usual 3 prong receptacle with the usual 14-2 with ground (or 12-2 with ground) Romex wiring down to the main panel with the usual green bonding screw in the neutral bus bar digging into the panel back and the usual shared neutral/ground/messenger with the two hot service conductors wrapped around it out to the utility pole. Except there is no fat ground wire (grounding electrode conductor) out of the panel and no ground rods (yet). Is the drill grounded? Is it bonded to ground?
__________________
Stop wasting time re-adjusting the pattern. Have several lawn sprinklers, one for each pattern.

Last edited by AllanJ; 11-15-2012 at 07:44 AM.
AllanJ is offline   Reply With Quote
Old 11-15-2012, 07:19 PM   #25
Member
 
Join Date: Feb 2010
Location: Oklahoma
Posts: 978
Rewards Points: 0
Default

ground rod


Quote:
Originally Posted by AllanJ
The code regarding ground rods is somewhat arbitrary. You need to achieve an impedance of 25 ohms or less between grounding electrode system and the earth, or drive two 8 foot ground rods, whichever comes first.

The simple meaning of a bond is an intended and essentially resistance free electrical connection, with the provision that, if A is bonded to B and B is bonded to C then A is bonded to C. (An unintended electrical connection is called a fault.)

Seems like we don't have enough words in the English language to describe things. Suppose we have an electric drill with the usual 3 prong plug in the usual 3 prong receptacle with the usual 14-2 with ground (or 12-2 with ground) Romex wiring down to the main panel with the usual green bonding screw in the neutral bus bar digging into the panel back and the usual shared neutral/ground/messenger with the two hot service conductors wrapped around it out to the utility pole. Except there is no fat ground wire (grounding electrode conductor) out of the panel and no ground rods (yet). Is the drill grounded? Is it bonded to ground?
The answer depends on who you're asking.
jlmran is offline   Reply With Quote
Old 11-15-2012, 07:44 PM   #26
JOATMON
 
ddawg16's Avatar
 
Join Date: Aug 2011
Location: S. California
Posts: 7,246
Rewards Points: 12
Default

ground rod


Quote:
Originally Posted by jlmran View Post
An absolutely totally different use of the earth.
You missed the point I was trying to make.....

Even with ground rods....we sometimes had to soak the earth to get a low resistance...

Hence, with a home setup....there is no real assurance that your going to get the 25 ohms with a single rod
__________________
"The dream is free but the hustle is sold separately."

My 2-Story Addition Build in Progress Link ... My Garage Build Link and My Jeep Build Link
ddawg16 is online now   Reply With Quote
Old 11-15-2012, 08:25 PM   #27
E2 Electrician
 
stickboy1375's Avatar
 
Join Date: Apr 2012
Location: Litchfield, CT
Posts: 5,089
Rewards Points: 0
Default

ground rod


And who even cares if you do have 25 ohms? I bet you could drive 100 rods and not get 25 ohms.
stickboy1375 is offline   Reply With Quote
Old 11-15-2012, 09:22 PM   #28
Member
 
Join Date: Feb 2010
Location: Oklahoma
Posts: 978
Rewards Points: 0
Default

ground rod


So...for residential electrical service purposes, what is the accepted procedure to actually determine/measure the resistance value? Is the procedure defined by the code? Does anybody execute it or do they simply drive 2 rods and forget about it?

I'm sure the Air Force communications discipline has its own procedure which may or may not differ?
jlmran is offline   Reply With Quote
Old 11-15-2012, 09:29 PM   #29
Member
 
Join Date: Aug 2010
Posts: 440
Rewards Points: 0
Default

ground rod


a megger
oleguy74 is offline   Reply With Quote
Old 11-15-2012, 09:38 PM   #30
Member
 
Join Date: Feb 2010
Location: Oklahoma
Posts: 978
Rewards Points: 0
Default

ground rod


Quote:
Originally Posted by oleguy74
a megger
That's a tool...not a procedure.

jlmran 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
To ground or not to ground Red Squirrel Electrical 2 10-14-2010 08:42 PM
Wiring an outlet using both ground screws instead of pig-tailing together. cabber24 Electrical 5 08-26-2010 08:40 AM
Electrical Ground Problem cabinetman Electrical 15 01-28-2010 04:55 PM
Live ground wire in dryer Retired sailor Electrical 10 05-04-2009 03:26 PM
Hot Tub Install--Grounding Rod Question statgeek_rob Electrical 16 09-15-2007 02:59 AM




Top of Page | View New Posts

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