Junction Box + Sub Panel

Reply

  #1  
Old 08-18-11, 07:25 PM
Member
Thread Starter
Join Date: Jul 2010
Location: USA
Posts: 80
Junction Box + Sub Panel

I am in the process of hooking up a subpanel in my laundry room. The wire run being run from my main circuit panel has a red, black, and white wire. I need to hook it up to a junction box and then continue it on to my subpanel. However, the wire that I'm connecting to it has a ground, black, and black with red stripe. This was the way it was originally hooked up when I moved it, I am just moving the subpanel and planned on using the same materials they had, but now I'm second guessing their set up. Also, the first wire is copper and the second is aluminum, should they both be the same? Any advice would be appreciated. Thank you!
 
Sponsored Links
  #2  
Old 08-18-11, 07:32 PM
Forum Topic Moderator
Join Date: Sep 2005
Location: USA
Posts: 4,259
You really shouldn't/cant extend a circuit without a ground wire. It would have had to be a really old installation as ground wires have been used since about the 60's (?). Also, the use use of aluminum is questionable, depending on the size of the wires. Larger circuits/subpanels are still run with aluminum, but you have to be sure to install them correctly. Also, an aluminum to copper connection needs to be done with something other than wire nuts.

All in all, you're going to have to run a new circuit from your main panel to your new subpanel. It'll be worth it since you'll then have a fully grounded subpanel to run new circuits.

Feel free to post back if you have questions on wire size and such.
 
  #3  
Old 08-18-11, 07:37 PM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 14,594
A feeder in the same building has been required to be 4 wires for many years. Since you are altering the circuit it would need to meet the current code.
 
  #4  
Old 08-19-11, 12:45 PM
Member
Thread Starter
Join Date: Jul 2010
Location: USA
Posts: 80
Thanks for the quick replies! So I'll be running a new 4-wire line. Right now, they have a double-pole 30 A breaker in the main panel, they used 8 gauge wire, is that correct or should I replace it with 10? Also, my main panel houses neutrals and grounds on the same bus, I know for my subpanel I had to install a grounding bus does this apply to main panels as well? Thanks again!
 
  #5  
Old 08-19-11, 01:08 PM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 33,058
So I'll be running a new 4-wire line. Right now, they have a double-pole 30 A breaker in the main panel, they used 8 gauge wire, is that correct or should I replace it with 10?
#10 would be adequate. #8 would give you the ability to up grade to 40 amp should you ever need it. Use cable cost to make that decision.

I know for my subpanel I had to install a grounding bus does this apply to main panels as well?
No. At the first OCPD (Over Current Protection Device) and only there ground and neutral are tied together.
 
  #6  
Old 08-19-11, 01:49 PM
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,515
Originally Posted by RyanNirg View Post
they used 8 gauge wire, is that correct or should I replace it with 10?
If the old #8 wire was aluminum, 30A was correct. Your new wire will probably be copper so #10 is correct for 30A. The real question though is what do you need the subpanel for? You should choose the size to match the appliance you intend to use, perhaps with some room for future growth.

Also, my main panel houses neutrals and grounds on the same bus, I know for my subpanel I had to install a grounding bus does this apply to main panels as well?
No, the main panel is the only place ground and neutral are together.
 
  #7  
Old 08-19-11, 02:00 PM
Member
Thread Starter
Join Date: Jul 2010
Location: USA
Posts: 80
Originally Posted by ibpooks View Post
The real question though is what do you need the subpanel for? You should choose the size to match the appliance you intend to use, perhaps with some room for future growth.
The subpanel will be used for an electric dryer, washing machine, and a handful of general purpose outlets!
 
  #8  
Old 08-19-11, 02:04 PM
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,515
In that case I would bump up to a 60A panel using #6-3/g cable. The electric dryer uses 100% of the 30A panel capacity leaving nothing left for the washer or other stuff.
 
  #9  
Old 08-22-11, 07:08 PM
Member
Thread Starter
Join Date: Jul 2010
Location: USA
Posts: 80
So just to confirm before I go out and buy the materials...I should replace the double bar 30A with a 60A in my main box and then run #6 wire from the main to the sub panel? Inside the sub, I have a double bar 30 for the dryer and 2 20's. Would one of the 20's be good for the washer and like 5 general purpose outlets or should I dedicate a 20 just for the washer? Thanks!
 
  #10  
Old 08-22-11, 07:44 PM
Justin Smith's Avatar
Member
Join Date: Dec 2010
Location: Cressona, Pa, USA
Posts: 2,546
I should replace the double bar 30A with a 60A in my main box and then run #6 wire from the main to the sub panel?
Yes. You need 6/3G.
Would one of the 20's be good for the washer and like 5 general purpose outlets or should I dedicate a 20 just for the washer? Thanks!
The washer should be on a dedicated.
 
  #11  
Old 08-23-11, 09:45 AM
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,515
Originally Posted by RyanNirg View Post
So just to confirm before I go out and buy the materials...I should replace the double bar 30A with a 60A in my main box and then run #6 wire from the main to the sub panel?
#6 cable, yes. Specifically #6-3/g NM-B which will contain black, red, white and bare wires. Make sure to get big enough cable clamps and wire staples to accommodate the larger cable.

Inside the sub, I have a double bar 30 for the dryer
Yep, and you use #10-3/g cable for this to a NEMA 14-30R receptacle. The dryer may need a matching four prong cord installed with neutral unbonded.

Would one of the 20's be good for the washer and like 5 general purpose outlets or should I dedicate a 20 just for the washer? Thanks!
By code, if the outlets are for the laundry area then they can share the 20A with the washer. However since you have the capacity there's no reason not to install a dedicated circuit for the washer. If the receptacles are in an unfinished basement or garage or within 6' of a sink they must be GFCI protected. Even if the receptacles don't meet the standard for mandatory GFCI protection, it would be a good idea in the laundry area.
 
Reply

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


Thread Tools
Search this Thread
Display Modes