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 01-12-2011, 12:24 AM   #1
Newbie
 
Join Date: Jan 2011
Posts: 6
Share |
Default

Grounding question


Hi all
I need advice on how to ground the new breaker box I am in the process of installing.
Here is how it looks like.
The house I bought had an old fuse box (200 amp service) in the basement I wanted to replace with a new breaker box.
The house receives power from a pole on the property. There is a 200 amp main disconnect (pullout fuse box) on the pole just beneath the meter. I've installed a new 200 amp breaker box in the basement (about 20' from the pole) and pulled 3 3/3/4 awg aluminum wires from main disconnect on the pole to the breaker box in an underground pvc conduit.
My question now is how to ground the system? As I understand the grounding should be via grounding wire and rod buried either near the breaker box or the main disconnect. But, do I also need to extend a grounding wire from the breaker box to the main disconnect on the pole? Also, as the house has a main disconnect on the pole, I do not know if the breaker box's neutral and ground buses should be bonded together or separate? The GE box I bought came as two buses connected at the bottom of the bars.
thanks in advance for your answers!

tmbleweed is offline   Reply With Quote
Old 01-12-2011, 12:57 AM   #2
Mad Scientist
 
Join Date: Dec 2009
Location: Minnesota
Posts: 762
Default

Grounding question


With a main disconnect out on the pole, the panel in your house is actually a sub panel. This means that you should have a separate ground wire from the outside disconnect to the house panel, along with your hots and neutral. The house panel should have grounds and neutrals separated on their own respective bars. This may require purchasing an add-on ground bar kit. You also still need two ground rods at the house, connected to the ground bar in the panel.

McSteve is offline   Reply With Quote
Old 01-12-2011, 01:08 AM   #3
Newbie
 
Join Date: Jan 2011
Posts: 6
Default

Grounding question


thank you!
The breaker box has a ground bar in addition to the neutral bar and they are connected with a bar at the bottom, which as I understand should be removed.
As I understand, the bare grounding copper wire I run from the main disconnect on the pole to the breaker box should be outside the conduit, then can I bury two rods along the way and clamp to that wire or should I run another grounding wire from the breaker box and clamp to two grounding rods outside the house?
thanks again
tmbleweed is offline   Reply With Quote
Old 01-12-2011, 01:11 AM   #4
Mad Scientist
 
Join Date: Dec 2009
Location: Minnesota
Posts: 762
Default

Grounding question


The ground wire from the disconnect should be run in the conduit with the other circuit conductors. You would run a separate wire from the new panel's ground bus to your ground rods.
McSteve is offline   Reply With Quote
Old 01-12-2011, 01:22 AM   #5
Newbie
 
Join Date: Jan 2011
Posts: 6
Default

Grounding question


Got it! thank you very much
It would be difficult to run the ground wire in the conduit as I glued half of it already, but I will try.
One last point though, if the ground wire from the pole to the breaker box is run in the conduit does it matter if its bare or insulated?
regards!
tmbleweed is offline   Reply With Quote
Old 01-12-2011, 01:26 AM   #6
Mad Scientist
 
Join Date: Dec 2009
Location: Minnesota
Posts: 762
Default

Grounding question


I think a ground wire in conduit can be either bare or insulated.

Are you gluing your conduit together with the wires in place? You really shouldn't. The glue can be harmful to the wire insulation, and you can easily end up with the wire glued to the conduit, making future replacement very difficult. All wires should be pulled at the same time through the completed conduit run.
McSteve is offline   Reply With Quote
Old 01-12-2011, 05:24 AM   #7
Master Electrician
 
Join Date: Nov 2008
Location: Northern Virginia
Posts: 465
Default

Grounding question


Quote:
Originally Posted by tmbleweed View Post
Hi all
Ipulled 3 3/3/4 awg aluminum wires from main disconnect on the pole to the breaker box in an underground pvc conduit.
what are 3 3/3/4 awg aluminum wires?? I hope that's not #3 wire for 200A.

Also, Code does require the complete installation of the conduit run before the conductors are installed.
busman is offline   Reply With Quote
The Following User Says Thank You to busman For This Useful Post:
Speedy Petey (01-12-2011)
Old 01-12-2011, 09:07 AM   #8
Licensed electrician
 
Join Date: Sep 2007
Location: Maryland
Posts: 7,406
Default

Grounding question


The raceway system is supposed to be complete before the conductors are pulled in to satisfy the electrical code.
__________________
Answers based on the National Electrical Code. Local amendments may apply. Check with your local building officials.
Jim Port is offline   Reply With Quote
Old 01-12-2011, 09:38 PM   #9
Newbie
 
Join Date: Jan 2011
Posts: 6
Default

Grounding question


Quote:
Originally Posted by busman View Post
what are 3 3/3/4 awg aluminum wires?? I hope that's not #3 wire for 200A.

Also, Code does require the complete installation of the conduit run before the conductors are installed.
The two aluminum wires (hots) i bought with the help of an electrician friend are thicker than minimum required and the neutral is 4/0. So it was quite difficult to run them through the 2" conduit. I thought about gluing the conduit before I run the wires, but given the thickness of the wires, it would have been almost an impossible job to run them from the basement to the pole with all the bends etc. I tried my best not to damage the wires inside while gluing the conduit.
Thanks for all your answers, they have been quite informative!
tmbleweed is offline   Reply With Quote
Old 01-12-2011, 09:57 PM   #10
Member
 
Join Date: Aug 2010
Posts: 440
Default

Grounding question


what gauge wire did you use?
oleguy74 is offline   Reply With Quote
Old 01-12-2011, 10:08 PM   #11
Newbie
 
Join Date: Jan 2011
Posts: 6
Default

Grounding question


Quote:
Originally Posted by oleguy74 View Post
what gauge wire did you use?
Ok I knew you people will make sure I have correct wire specs. Give me half an hour, I need to go out to the snow and write down wire specs.
tmbleweed is offline   Reply With Quote
Old 01-12-2011, 10:27 PM   #12
Newbie
 
Join Date: Jan 2011
Posts: 6
Default

Grounding question


It is dark and cold outside, I tried to copy what is printed on the wires, I might have misread one letter or two...
Hot wires: Southwire (UL) KCMI AL USE 2 95 MILS XLP insulation ...600 volts
Neutral: Southwire (UL) AWG 4/0 AL Type USE 2
As I said, hot wires are thicker than the neutral.
I hope i have correct wire specs!

tmbleweed is offline   Reply With Quote
Reply

Tags
breaker box, grounding, main disconnect


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
Outlet grounding question handyd123 Electrical 5 11-28-2010 02:15 PM
Grounding a Square Box <--newbie question dgates12 Electrical 20 01-06-2010 06:02 PM
Basement Renovation Question KUIPORNG Remodeling 234 08-26-2008 08:19 AM
grounding to water pipe question eastvantrading Electrical 6 12-20-2006 09:49 AM
Question on Grounding ayudi General DIY Discussions 2 12-11-2006 04:14 AM




Top of Page | View New Posts

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