Forums | Home Repair | Home Improvement | Painting | Interior Decorating | Remodeling | Landscaping


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 11-24-2009, 04:11 PM   #1
Member
 
Join Date: Oct 2006
Posts: 137
Share |
Default

Question about underground wire type


My ultimate goal is to put a sub-panel in my garage. Right now I'm just trying to figure out if I can use the wire I already have to do it and save a few hundred dollars. Here is a list of what I have:
Black #6 wire marked 600v THW
White #6 marked MTW (Machine Tool Wire) THW 600v
Red #6 I think it's marked the same as the white but I can't read it clearly
Blue unmarked, it's #6 and looks identical to the white
So is any of this safe to use underground in conduit?

What about indoors? I need to run about 60' to the panel indoors. I know I can't just run individual connectors across the basement. I should be safe keeping them in conduit though, right? What's the smallest size conduit I can legally keep them in indoors?

Last edited by Tmb9862; 11-24-2009 at 04:16 PM.
Tmb9862 is offline   Reply With Quote
Old 11-24-2009, 04:17 PM   #2
Member
 
Join Date: Oct 2006
Posts: 137
Default

Question about underground wire type


Ok, the red definatly says "MTW -- Type THW"
Tmb9862 is offline   Reply With Quote
Old 11-24-2009, 04:56 PM   #3
Member
 
Join Date: Jan 2009
Location: South of Boston, MA
Posts: 17,248
Default

Question about underground wire type


Where are you located ?
Is the garage attached or detached ?
I'm thinking attached since you indicate indoors, you can run conduit indoors
For a sub you need 4 wires, 2 hots, white neutral & green ground (#8 will work for green)

I used 1" conduit for my 60a sub w/#6 wire, easier to pull
Scuba_Dave is offline   Reply With Quote
Old 11-24-2009, 05:05 PM   #4
Member
 
Join Date: Oct 2006
Posts: 137
Default

Question about underground wire type


I am located in NY.
The garage is detached. I have about 40' between the garage and the house. The panel is on the opposite end of the house so I need to go about 60' across the basement.

Actually wiring the panel is a whole different animal. I'm not quite sure how to do that and was going to research it further. I was looking at a sub-panel in a detached garage in a new house today. It looks like they only ran two hots and a neutral, the ground goes outside to a ground rod.

Right now I'm just curious if I can use the wire I already have. I do have black #8 type TW. If I do have to run a #8 from the main to the sub panel could I just use that and wrap the ends in green electric tape?

Last edited by Tmb9862; 11-24-2009 at 05:12 PM.
Tmb9862 is offline   Reply With Quote
Old 11-24-2009, 05:10 PM   #5
Member
 
Join Date: Jan 2009
Location: South of Boston, MA
Posts: 17,248
Default

Question about underground wire type


OK, for detached you will also need 2 ground rods at the sub panel connected with #6 min wire
Neutral must not be bonded to the panel (remove green screw) & neutrals & grounds must be on seperate bus
Conduit must run from panel to panel

3 wires is old Code
New code requires 4 wire & ground rods
Check with local code for local changes/requirements
Scuba_Dave is offline   Reply With Quote
Old 11-24-2009, 06:31 PM   #6
Electrical Contractor
 
jbfan's Avatar
 
Join Date: Jun 2004
Location: Newnan GA
Posts: 5,472
Default

Question about underground wire type


Unless the wire also has a W, like thwn, it can not be used is a wet location, and underground conduit is considered a wet location.
__________________
Yes I am a Pirate, 200 years too late. "Jimmy Buffett"
jbfan is offline   Reply With Quote
Old 11-24-2009, 07:25 PM   #7
Electrical Contractor
 
kbsparky's Avatar
 
Join Date: Sep 2008
Location: Delmarva
Posts: 3,352
Default

Question about underground wire type


You can use a 1" or 1" PVC conduit for this project. You will need an equipment grounding conductor, minimum #10 green or bare conductor (You can strip off the insulation of the entire length of one of your #6 pieces if you want).

You are not permitted to use green tape on conductors #6 and smaller, but I have seen this practice done many times using #8 and even #10 wires ..
__________________
-KB

Life is uncertain -- eat dessert first!!
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
kbsparky is offline   Reply With Quote
Old 11-24-2009, 11:30 PM   #8
Member
 
Join Date: Oct 2006
Posts: 137
Default

Question about underground wire type


Quote:
Originally Posted by jbfan View Post
Unless the wire also has a W, like thwn, it can not be used is a wet location, and underground conduit is considered a wet location.
It's not THWN, it's THW. The black #6 is "THW". The red and white are "MTW - type THW". The #8 and #10 I have are type TW. So these should all be good to go in underground conduit as they have a W in them?
Tmb9862 is offline   Reply With Quote
Old 11-25-2009, 06:04 PM   #9
Electrical Contractor
 
jbfan's Avatar
 
Join Date: Jun 2004
Location: Newnan GA
Posts: 5,472
Default

Question about underground wire type


Quote:
Originally Posted by Tmb9862 View Post
It's not THWN, it's THW. The black #6 is "THW". The red and white are "MTW - type THW". The #8 and #10 I have are type TW. So these should all be good to go in underground conduit as they have a W in them?
The thw is good for 65 amps, but I can not not the ampacitiy for mtw.
The tw is 30 amps for the #10 and 40 amps for the #8.
You can not remark any of the wires you have to green, so you would have to buy a green wire.
All of these wires are good for a wet location.
__________________
Yes I am a Pirate, 200 years too late. "Jimmy Buffett"
jbfan is offline   Reply With Quote
Old 11-26-2009, 10:35 AM   #10
Member
 
Join Date: Oct 2006
Posts: 137
Default

Question about underground wire type


Thank you, that's what I needed.

A couple more things I'm not positive on.

What size ground do I need going to the main panel and what size grounds do I need going to the rods? There are two replies there saying #8 and #10.

Do I need a main lug or a main breaker panel? If I need a main breaker can I use a panel with a 100 amp main breaker so long as it's protected by the 60 on the main panel or do I need to install a 60 amp main breaker in it?

What is the proper depth for the conduit?

Last edited by Tmb9862; 11-26-2009 at 10:38 AM.
Tmb9862 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
Finding underground electric wire for driveway lights. mitch21131 Electrical 25 09-24-2012 08:52 AM
2 Wire Thermostat question vtec69 Electrical 19 10-19-2009 05:14 PM
Thermostat Wire Question TJ_in_IL HVAC 5 10-16-2009 05:57 PM
Ground Clamps Question integlikewhoa Electrical 40 02-28-2008 09:13 PM
Wire size for distance Question fburke Electrical 4 07-28-2007 09:29 AM




Top of Page | View New Posts

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