ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
ShoutChat
Recent Posts
Where is Everyone?
by gfretwell - 06/20/21 10:53 PM
Happy Father's Day!
by Bill Addiss - 06/19/21 04:16 PM
A Risky Setup
by timmp - 06/18/21 08:08 PM
Conduit over Vinyl Siding
by Jim M - 06/16/21 08:30 PM
Updated Forum Software
by Admin - 06/15/21 10:23 AM
New in the Gallery:
2020 - 2021 Winter Project
2020 - 2021 Winter Project
by Bill Addiss, April 29
Garden 2021
Garden 2021
by Bill Addiss, April 26
Who's Online Now
1 members (Scott35), 13 guests, and 15 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Page 1 of 2 1 2
#93065 04/30/05 10:33 PM
Joined: Jan 2004
Posts: 1,507
G
Member
Should the ground rod installed for lightning protection measure less than 25 ohms to ground?

[This message has been edited by George Little (edited 04-30-2005).]


George Little
2017 / 2014 NEC & Related Books and Study Guides
#93066 04/30/05 10:48 PM
Joined: Jun 2003
Posts: 681
P
Member
George
That is a good question.I looked in a few of my resources and did not see any minimum value given as a point of reference.
I did see a minimum of an 8 ft ground rod that shall extend 10 feet vertically in the earth.


Pierre Belarge
#93067 05/01/05 12:53 AM
Joined: Feb 2005
Posts: 693
L
Member
"...an 8 ft ground rod that shall extend 10 feet vertically..."

This I gotta see!

[This message has been edited by Larry Fine (edited 05-01-2005).]


Larry Fine
Fine Electric Co.
fineelectricco.com
#93068 05/01/05 06:45 AM
Joined: Apr 2005
Posts: 6
R
Junior Member
simple, dig a hole 2 ft deep and drive the rod to the bottom, cover with dirt

#93069 05/01/05 09:51 AM
Joined: Mar 2002
Posts: 582
R
Ron Offline
Member
Because that lightning protection ground rod gets bonded to the building's grounding electrode system, your results/regulation is by the NEC (more than one rod, no maximum resistance).
NFPA 780 doesn't have a maximum resistance established that I'm aware of.


Ron
#93070 05/01/05 09:53 AM
Joined: Jun 2003
Posts: 681
P
Member
Larry
That is a requirement from NFPA 780-Standard for the Installation of Lightning Protection Systems.
3.13.1 & 3.13.1.1
Ths standard has an illustration that shows an 8' groundrod buried 2' to make up the 10' vertical burial depth.

I have seen this done many times, as it seems the big homes and larger office buildings are all installing lightning protection these days.


Pierre Belarge
#93071 05/01/05 12:08 PM
Joined: Jul 2004
Posts: 9,646
G
Member
If you do a radio tower you will see guys who are serious about ground electrodes.
I inspected a bunch of Florida DOT "radio equipment shelters" (the little shack under the tower).
They use a Ufer, coupled to ground rods (up to 40') at the corners, a ground ring and buried radials out from there. Everything is cadwelded.


Greg Fretwell
#93072 05/01/05 12:14 PM
Joined: Jan 2003
Posts: 4,391
I
Moderator
Greg don't you live in the lightning capitol of the world?


Bob Badger
Construction & Maintenance Electrician
Massachusetts
#93073 05/01/05 05:52 PM
Joined: Feb 2005
Posts: 693
L
Member
Yes, Roxie and PC, I knew that. It just struck me funny the way you (PC) worded it.

About two years ago, we did the ground work for a cellular phone tower. Rods every four feet along the ground ring, which was solid #2 tinned copper, and all spliced exothermically welded; all in a 2'+ ditch.


Larry Fine
Fine Electric Co.
fineelectricco.com
#93074 05/02/05 11:25 AM
Joined: Apr 2002
Posts: 7,275
Likes: 2
Member
Insight from another northern guy....what about a 10' x 3/4" rod????

BTW, anoyone ever install Lyncole Grounding devices?? Now that was a 'trip'!

John


John
Page 1 of 2 1 2

Link Copied to Clipboard
Featured:

Tools for Electricians
Tools for Electricians
 

* * * * * * *

2020 Master Electrician Exam Preparation Combos
2020 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Member Spotlight
MarkC10
MarkC10
CA, Inland Empire
Posts: 43
Joined: September 2013
Top Posters(30 Days)
Admin 10
Trumpy 8
Popular Topics(Views)
280,460 Are you busy
213,547 Re: Forum
200,418 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.7.5