UF Wiring

Reply

  #1  
Old 08-08-15, 02:02 PM
Member
Thread Starter
Join Date: Aug 2015
Location: USA
Posts: 11
UF Wiring

Hello,

I have a subpanel that was fed from the main without a ground. The house was from the 50's and nearly all of the circuits in the home are ungrounded. This subpanel was the original main panel location. I would like to rewire the whole house eventually, but first I need to get a ground wire from the main panel to this sub-panel.

I am looking to use UF 8/3 with ground to update the wiring. The main breaker is outside, and the sub-panel is inside the home. Do I need to use conduit for the entire run to get the UF wire to the attic where I can then access the sub-panel? Or can some of the UF wire be exposed? Currently the wire that feeds the sub-panel is in conduit, but I would like to limit the amount of conduit on the outside of the house if I can.

Thanks for any help!
 

Last edited by Azdiywannabe; 08-08-15 at 02:27 PM.
Sponsored Links
  #2  
Old 08-08-15, 03:00 PM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 32,669
The main breaker is outside,
What is the wall on the other side of the main panel?

I see two options to no conduit and no UF cable.
  • Drop a cable through the wall from the attic and come in to the back of the main panel. You can use NM-b if you do it that way.
  • Put a weather proof box beside or be low the main panel and come into it from the back. A short nipple (1"-1") would connect it to the panel. You'd transition from NM-b to THWN for the short run into the panel.

Whether you go into the panel or a junction box I'd cut a hole in the inside wall to allow for fishing the cable. Being bad at Sheetrock patching I'd make the hole the size of a one or two gang box. Since the opening would only be for access and no connections when finished fishing the cable I'd put in a low voltage old-work ring to hold a blank cover plate to cover the opening... or just patch the Sheetrock.
 
  #3  
Old 08-08-15, 03:23 PM
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,374
Currently the wire that feeds the sub-panel is in conduit,...
What kind of conduit? Is it plastic or metal? If metal does it have threaded ends or adapters that provide threads?

IF it is metal it is quite possible the conduit itself is the equipment grounding conductor. You can test this by testing for voltage (with an analog meter or solenoid tester) from each feeder connection in the sub-panel to the metal of the sub-panel; each should give a reading of about 120 volts and each reading should be equal.

If it is plastic conduit OR the voltage check fails, then tell us what the nominal size of the conduit is and the size of the individual conductors in the conduit. If it is large enough the easiest fix is to just add the equipment grounding conductor to the existing conduit.
 
  #4  
Old 08-08-15, 04:31 PM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 32,669
Furd's advice is the way to go if you can live with the conduit. Mine was based on your statement:
I would like to limit the amount of conduit on the outside of the house if I can.
 
  #5  
Old 08-09-15, 10:25 AM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: USA
Posts: 9,221
I am looking to use UF 8/3 with ground to update the wiring.
Can the entire house get by with just 40 amps?
 
  #6  
Old 08-09-15, 10:55 AM
Member
Thread Starter
Join Date: Aug 2015
Location: USA
Posts: 11
Hello, I have attached, or hopefully I have, a picture of my sub panel. I have tested the voltage across the neutral bar and the feeder wires it tests at 120V, however if I test it to the actual metal box it does not register any ground. Does this mean the conduit does not continue entirely to the panel?

It is a metal conduit, it does not appear to have threaded connections.

I intend to add a grounding bus and then ground all the circuits to that as I rewire them.

Thanks again!

Name:  54416d1439142672-uf-wiring-img_2018.jpg
Views: 75
Size:  34.8 KB
 

Last edited by PJmax; 08-09-15 at 02:51 PM. Reason: reoriented/enhanced picture
  #7  
Old 08-09-15, 11:00 AM
chandler's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Dec 2005
Location: USA
Posts: 39,968
Have you seen the metal conduit? I see sheathed cables, which would indicate no conduit, but anything is possible in the 50's. I do note the sheetrock screws through the body, so it was added sometime later, I presume. Was this originally a fuse panel?
 
  #8  
Old 08-09-15, 11:26 AM
Member
Thread Starter
Join Date: Aug 2015
Location: USA
Posts: 11
The conduit is outside the house. There is about 3 ft of wall to the right of this box. This was the original fuse box from the home. Sometime in the 80's the wiring was redone, and a new main was added outside, about 15 feet away under the porch roof line. Conduit is run from the new(er) panel along the exterior brick and at least into the attic. I tried to peek between the panel and the drywall, its hard to see, but it does not appear to have conduit all the way to the panel.
 
  #9  
Old 08-09-15, 01:51 PM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 32,669
if I test it to the actual metal box it does not register any ground. Does this mean the conduit does not continue entirely to the panel?
Most likely or even if it does there is a fault which means it can not be used as a ground.

Tell us about the loads on this panel? You mentioned using #8 but I iwouldn't use less than #6. Is there a label on the panel that says it is a 60 amp panel?
 
  #10  
Old 08-09-15, 02:41 PM
Member
Thread Starter
Join Date: Aug 2015
Location: USA
Posts: 11
This is the sub-panel. It currently has 3 bedrooms, 1.5 bathrooms (neither has outlets in the room, only a light and fan), the dining room, family room, the garage (converted car port), a couple of outlets in a storage room attached to the garage. So 21 outlets, 4 ceiling fans, the fridge, garage door, 1 bath exhaust fan and two bathroom light fixtures. The Range, stove top, microwave, dishwasher, the AC, washer/dryer, and water heater are all connected to the main panel outside that is grounded. This was done in a remodel many years before I owned this house.

The panel is connected to a double pull 40A breaker in the main panel.

Thanks for all your help!
 
  #11  
Old 08-09-15, 03:52 PM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 32,669
If it hasn't tripped the 40 amp then you are okay but I'd still use #6 and a 60 amp breaker just to give yourself a little extra head room. Or stay with the 40 amp breaker but use #6 so it was future r proofed to some extant.
 
  #12  
Old 08-09-15, 08:27 PM
Member
Thread Starter
Join Date: Aug 2015
Location: USA
Posts: 11
So I just want to clarify, I would use #6 UF cable, would I need to put it in conduit to get it to the sub panel for any portions it would be outside of the house?

Thanks
 
  #13  
Old 08-09-15, 09:30 PM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 32,669
So I just want to clarify, I would use #6 UF cable, would I need to put it in conduit to get it to the sub panel for any portions it would be outside of the house?
Did you read my post #2?

If you want to run it in conduit use individual conductors such as THWN the transition to NM-b and no conduit where you enter the attic.
 
  #14  
Old 08-10-15, 06:13 AM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 14,361
It sounds like a sleeve was used to protect the cable running up the wall. Do you have a picture of outside?
 
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
'