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 10-05-2009, 11:58 AM   #1
Newbie
 
Join Date: Oct 2009
Posts: 5
Rewards Points: 10
Default

old house wiring...not code


I bought an old house....In the attic there is a 10gauge run of (old)Romex which contains 2 insulated wires and a bare ground. It comes from the main panel and is attached to a 2 pole 30 amp breaker. Ground wire on ground/neutral bus. So far so good This wire in the attic enters a subpanel wherein the 2 hots are on the breaker bars and the ground wire is on the neutral bar. There is no 4th wire or equipment ground bar. This subpanel then has one 15 amp single pole breaker which then feeds some ceiling lights.

So while this is a code violation, what is the specific risk here? By code a ground and neutral wire go to the same bar in the main panel anyway, and the lights work fine.....let me have it, I am sure this is obvious but dont know.

Thanks

fisherman2001 is offline   Reply With Quote
Old 10-05-2009, 12:57 PM   #2
Licensed Electrician
 
Magnettica's Avatar
 
Join Date: Jan 2009
Location: Rahway, NJ
Posts: 168
Rewards Points: 150
Send a message via Yahoo to Magnettica
Default

old house wiring...not code


The bare wire is being used as a neutral and it needs to be insulated, it is not.

Also, because the bare wire is being used a neutral, you therefore have no equipment ground.

Why is this bad? Because in the event you have a "ground fault" there is no conductor to carry the ground fault current back to the source.

Worst case scenario is the panel provides only 120 volts. Be sure the equipment grounding buss is isolated from the neutral to prevent objectionable current flow.

__________________
Union County, NJ, Licensed Electrician
Classic Electric, LLC, Rahway, New Jersey
Magnettica is offline   Reply With Quote
Old 10-05-2009, 04:10 PM   #3
Member
 
Join Date: Mar 2009
Posts: 780
Rewards Points: 500
Default

old house wiring...not code


The easiest thing to do is replace the double pole breaker in the main panel with a single pole breaker, connect the white wire the the buss. Then in the sub panel connect the white wire to the buss.
hayewe farm is offline   Reply With Quote
Old 10-05-2009, 06:42 PM   #4
Member
 
Join Date: May 2008
Location: Near Philly
Posts: 2,041
Rewards Points: 1,002
Default

old house wiring...not code


Isn't the bare wire now a neutral on a 120 v circuit if Hayewe's idea is used?
Still an issue I would think?
bob22 is offline   Reply With Quote
Old 10-05-2009, 09:16 PM   #5
Member
 
Join Date: Oct 2007
Posts: 2,294
Rewards Points: 1,000
Default

old house wiring...not code


Quote:
So while this is a code violation, what is the specific risk here?
Picture this. Better yet, draw it.

In a specific fault condition, which is not highly unlikely in a lot of cases, your neutral to "sub" panel gets broken/disconnected/burned...faulted connection somehow.

Neutral and ground wire in sub are on the same bus.

You have something grounded.....let's say a refrigerator..... plugged in to one or more of the circuits supplied by the panel.

The current from the breaker will be going thru the refer and back on the neutral but it can't make it's way back to the neutral/ground at the main source so it will travel thru the ground back to the refer recep, thru the grond pin on the plug and energize the metal frame of the refer. When you grab the refer barefoot, you will complete the circuit.

If there is a garage door plugged into a branch circuit from that panel, the whole garage door and hardware will be a possible path for the current and a barefoot kid playing in the driveway becomes a conductor.

The possibilities are many.

The same thing can and does happen at the service but by making the service the only place it's allowed minimizes the risk.
220/221 is offline   Reply With Quote
Old 10-05-2009, 09:48 PM   #6
Electrical Contractor
 
jbfan's Avatar
 
Join Date: Jun 2004
Location: Newnan GA
Posts: 5,855
Rewards Points: 2,106
Default

old house wiring...not code


Quote:
Originally Posted by bob22 View Post
Isn't the bare wire now a neutral on a 120 v circuit if Hayewe's idea is used?
Still an issue I would think?
He would need to add a ground bar and seperate the ground and neutral.
__________________
Yes I am a Pirate, 200 years too late. "Jimmy Buffett"
jbfan is offline   Reply With Quote
Old 10-05-2009, 09:52 PM   #7
Member
 
Join Date: Jan 2009
Location: South of Boston, MA
Posts: 17,248
Rewards Points: 2,000
Default

old house wiring...not code


Yes...the specific risk is death
Many unsafe wires in an older house
I had more then my share at my old house - built in 1905
Rewired by a hack around 1979
Scuba_Dave is offline   Reply With Quote
Old 10-05-2009, 10:03 PM   #8
Member
 
Join Date: May 2009
Location: Brooklyn, New York (NYC)
Posts: 1,124
Rewards Points: 500
Thumbs up

old house wiring...not code


Quote:
Originally Posted by bob22 View Post
Isn't the bare wire now a neutral on a 120 v circuit if Hayewe's idea is used?
Still an issue I would think?
No. Because, this now a 120V. circuit, the White wire (originally part of a MWBC) IS the NEUTRAL! And the bare wire is GROUND. ....And everything is fine and dandy.. And they lived happily ever after. (You've got to inject some light Humor in the most serious of situations.! (No matter what) Don't Drink and Drive. Ever!!!
spark plug is offline   Reply With Quote
Old 10-06-2009, 08:17 AM   #9
Member
 
Join Date: Aug 2009
Posts: 133
Rewards Points: 75
Default

old house wiring...not code


I am assuming it should be 15 or 20A maximum as it is used for a lighting circuit. The existing 10GA wire can handle 30A (depending on total length of the run), but will placing ceiling fuxtures on a 30A circuit cause another code non-compliance?
MI-Roger is offline   Reply With Quote
Old 10-06-2009, 08:18 AM   #10
Member
 
Join Date: Nov 2007
Location: Nashua, NH, USA
Posts: 6,964
Rewards Points: 2,024
Default

old house wiring...not code


Double check the ground/neutral bus bar in the subpanel. If it has metal-metal contact with the panel frame, you need to install a neutral bus with a plastic liner and no such metal to metal contact. If not then you need to install a ground bus (with such metal to metal contact). Move the white and bare wires to match (after making sure that the other end of the white feed line down at the main panel has been moved to the neutral bus there first).

The breaker(s) in the subpanel for ordinary branch circuits would be/stay 15 and/or 20 amps. Lights and regular receptacles may be on a circuit (or subcircuit if you insist) of at most 20 amps.

The subpanel is there to prevent putting lights and receptacles directly on a 30 amp circuit which the 10 gauge wires going to the main panel can stay as.
__________________
Forget super sized fries. The Washington Redskins could promote healthy eating with First Lady Obama by choosing a (red skinned) turnip for a mascot.

Last edited by AllanJ; 10-06-2009 at 08:33 AM.
AllanJ is online now   Reply With Quote
Old 10-06-2009, 08:22 AM   #11
Licensed Pro
 
Join Date: Mar 2007
Location: SC
Posts: 1,542
Rewards Points: 1,000
Default

old house wiring...not code


Quote:
Originally Posted by MI-Roger View Post
I am assuming it should be 15 or 20A maximum as it is used for a lighting circuit. The existing 10GA wire can handle 30A (depending on total length of the run), but will placing ceiling fuxtures on a 30A circuit cause another code non-compliance?
Maximum breaker size for 120V lighting and receptacles in a dwelling is 20A.
__________________
"Life is hard. Life is harder when you're stupid." John Wayne
HouseHelper is offline   Reply With Quote
Old 10-06-2009, 08:24 AM   #12
Electrical Contractor
 
jbfan's Avatar
 
Join Date: Jun 2004
Location: Newnan GA
Posts: 5,855
Rewards Points: 2,106
Default

old house wiring...not code


Quote:
Originally Posted by MI-Roger View Post
I am assuming it should be 15 or 20A maximum as it is used for a lighting circuit. The existing 10GA wire can handle 30A (depending on total length of the run), but will placing ceiling fuxtures on a 30A circuit cause another code non-compliance?
He is feeding the panel with the 30 amp, and has 1 15 amp lighting circuit from the panel.
__________________
Yes I am a Pirate, 200 years too late. "Jimmy Buffett"
jbfan is offline   Reply With Quote
Old 10-06-2009, 08:39 AM   #13
Member
 
Join Date: Aug 2009
Posts: 133
Rewards Points: 75
Default

old house wiring...not code


Why even keep the sub-panel? It only feeds one circuit ,which can be just as easily fed from the mainpanel using the existing 10GA NMC and a new single pole breaker of appropriate size.

Doesn't the code require all panels and all breakers to be easily accessible? I would not consider a sub-panel located in an attic to qualify as easily accessible. Removing the subpanel would eliminate a lot of potential problems.

My assumption was that this panel would be eliminated.
MI-Roger is offline   Reply With Quote
Old 10-06-2009, 07:30 PM   #14
Member
 
Join Date: Oct 2007
Posts: 2,294
Rewards Points: 1,000
Default

old house wiring...not code


Quote:
Why even keep the sub-panel? It only feeds one circuit ,which can be just as easily fed from the mainpanel using the existing 10GA NMC and a new single pole breaker of appropriate size.
Why didn't I think of that?

220/221 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
house insurance company wants to inspect my house! Knucklez General DIY Discussions 63 07-16-2013 08:05 PM
Connecting main house to guest house... hlavine Building & Construction 31 03-28-2012 09:04 AM
Fixing weekend house staining that went awry jb888s Painting 10 08-17-2009 10:01 PM
Moving a House 70 miles- Practical? GOTHICrevivalRULES Building & Construction 19 11-27-2008 08:58 PM
House Wiring Help please FwuffyTheBunny Electrical 1 07-12-2007 10:46 PM




Top of Page | View New Posts

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