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 08-24-2010, 02:29 PM   #1
Member
 
Join Date: Mar 2010
Posts: 32
Share |
Default

20A Breaker, 14 gauge wire?


I'm upgrading my panel and need to buy the new breakers. Some of the circuits are new but most of them will be swung over from my existing panel which is a 40A with push-button type breakers from the 1950s. All of the existing wire in my house is the black cloth-covered NM wire with no ground. All of the breakers are 20A but as far as I can tell, the existing wire appears to be #14. I am basing this guess on the fact that it looks slightly smaller than new #12 ROMEX and also the fact that you can push this older wire into the holes on outlets and switches where the new #12 will not fit and has to be attached by screws.

I know that 14 gauge wire has to be on a 15A breaker and that's what I plan to do unless someone here can give me a reason why this old wire would be safe for a 20A breaker.

Was this a mistake made when the house was built? Were wire ratings downgraded some time in the past for safety reasons? Or is there a possibility that this older wire is somehow rated for 20A even though it appears to be smaller than 12 gauge?

joside is offline   Reply With Quote
Old 08-24-2010, 04:22 PM   #2
Member
 
Join Date: Jul 2008
Location: NW of D.C.
Posts: 5,990
Default

20A Breaker, 14 gauge wire?


Quote:
Originally Posted by joside View Post
the existing wire appears to be #14.
looks slightly smaller than new #12 ROMEX
you can push this older wire into the holes on outlets and switches where the new #12 will not fit
#12 is 5/64" in diameter, #14 is 4/64" = 2/32" = 1/16".

If you wrap 10 turns of each around a dowel and measure the length of your new "coil" it will be easy to measure the diameters to pretty good precision with just a ruler. No micrometer needed. Just divide the coil length by 10.

Yoyizit is offline   Reply With Quote
Old 08-24-2010, 04:22 PM   #3
Electrical Contractor
 
kbsparky's Avatar
 
Join Date: Sep 2008
Location: Delmarva
Posts: 3,368
Default

20A Breaker, 14 gauge wire?


Change `em to the proper size. You can check the wire size using the slots in a pair of wire strippers, or an AWG gauge (not to scale):

__________________
-KB

Life is uncertain -- eat dessert first!!
kbsparky is offline   Reply With Quote
Old 08-24-2010, 04:59 PM   #4
Member
 
Join Date: Mar 2010
Posts: 32
Default

20A Breaker, 14 gauge wire?


Unfortunately I won't be changing them because that would mean busting tons of holes in my plaster walls and is not a project I want to tackle at the moment. Maybe at a future date. Thanks for the tips on sizing.
joside is offline   Reply With Quote
Old 08-24-2010, 05:09 PM   #5
Member
 
Join Date: Mar 2010
Location: New York
Posts: 1,737
Default

20A Breaker, 14 gauge wire?


If you do decide that they are 14 guage, you are safer to replace those breakers with 15 amps then change back to 20 amp when you upgrade the wire. It's better to trip a circuit breaker than fry a wire.
Jim F is offline   Reply With Quote
Old 08-24-2010, 07:07 PM   #6
nap
You talking to me?
 
nap's Avatar
 
Join Date: Dec 2007
Location: sw mi
Posts: 5,407
Default

20A Breaker, 14 gauge wire?


Quote:
Originally Posted by kbsparky View Post
Change `em to the proper size. You can check the wire size using the slots in a pair of wire strippers, or an AWG gauge (not to scale):

[i
I wouldn't count on the strippers. I have some that are basically a full size off. I use the #14 for #12 wire, #12 for #10 and on and on.

that wire gage is kind of funny. They provide a hole of the proper size but rather than just punching the right sized hole, they put an undersized slot to the edge. Why?
nap is offline   Reply With Quote
Old 08-24-2010, 07:17 PM   #7
Member
 
Join Date: Oct 2007
Posts: 204
Default

20A Breaker, 14 gauge wire?


Quote:
Originally Posted by kbsparky View Post
Change `em to the proper size.
yeah why not just build a new house too while you're at it
johnnyboy is offline   Reply With Quote
Old 08-24-2010, 07:49 PM   #8
Member
 
Join Date: Dec 2008
Posts: 162
Default

20A Breaker, 14 gauge wire?


Quote:
Originally Posted by nap View Post
I wouldn't count on the strippers. I have some that are basically a full size off. I use the #14 for #12 wire, #12 for #10 and on and on.

that wire gage is kind of funny. They provide a hole of the proper size but rather than just punching the right sized hole, they put an undersized slot to the edge. Why?
You poke the wire in to the hole from the back. if it can slide out the slot, it's the next smaller size. Without the slot, you could poke a #14 wire into the #12 hole, and it would fit, and you might misidentify the wire.
moondawg is offline   Reply With Quote
Old 08-24-2010, 08:56 PM   #9
nap
You talking to me?
 
nap's Avatar
 
Join Date: Dec 2007
Location: sw mi
Posts: 5,407
Default

20A Breaker, 14 gauge wire?


Quote:
Originally Posted by moondawg View Post
You poke the wire in to the hole from the back. if it can slide out the slot, it's the next smaller size. Without the slot, you could poke a #14 wire into the #12 hole, and it would fit, and you might misidentify the wire.
makes sense. I can't tell from the pic if it is that way so I'll take your word for it.

so, in other words, it's a go/no go style gauge.
nap is offline   Reply With Quote
Old 08-25-2010, 06:06 AM   #10
Electrical Contractor
 
kbsparky's Avatar
 
Join Date: Sep 2008
Location: Delmarva
Posts: 3,368
Default

20A Breaker, 14 gauge wire?


The slot is what reads the wire size, NOT the holes.
__________________
-KB

Life is uncertain -- eat dessert first!!
kbsparky is offline   Reply With Quote
Old 08-25-2010, 06:31 AM   #11
Member
 
Join Date: Mar 2007
Location: Eighty Four, Pa.15330
Posts: 1,241
Default

20A Breaker, 14 gauge wire?


Yoyizit, Never heard of that method.

Last edited by bobelectric; 08-25-2010 at 06:33 AM.
bobelectric is offline   Reply With Quote
Old 08-25-2010, 06:31 AM   #12
Master Electrician
 
Join Date: Nov 2008
Location: Northern Virginia
Posts: 477
Default

20A Breaker, 14 gauge wire?


Quote:
Originally Posted by nap View Post
I wouldn't count on the strippers. I have some that are basically a full size off. I use the #14 for #12 wire, #12 for #10 and on and on.
It's possible you are reading the numbers for stranded wires on your strippers. #12 stranded fits well in the #10 solid hole and so on. Some strippers are marked for both stranded and solid and show this "one-size-off" phenomenon.

Mark
busman is online now   Reply With Quote
Old 08-25-2010, 09:41 AM   #13
Member
 
Join Date: Jul 2008
Location: NW of D.C.
Posts: 5,990
Default

20A Breaker, 14 gauge wire?


Quote:
Originally Posted by bobelectric View Post
Yoyizit, Never heard of that method.
Thank you . . .I think

I never thought I would give anyone credit for being curious, but
I have to give you credit for being curious.

If you get a wire size using this method that comes out between sizes, like AWG #13 which is 0.072" inches in diameter, or some other unlikely answer, use 20 turns and divide by 20 and use a ruler graduated in 32nds or 64ths.

I don't know of a wire manuf. deliberating putting less copper in Romex that is marked with a certain size, but, hey, this is America! Who's to know?


Last edited by Yoyizit; 08-26-2010 at 10:32 AM.
Yoyizit 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
GFCI Breaker Tripping Spa Light eaposition Electrical 21 09-08-2010 09:57 PM
ROMEX 14-2 wire from Canada Vs. ROMEX 14-2 wire from the U.S. Dazzlin Electrical 14 06-04-2010 07:51 AM
Neutral Wire? 4x15mph Electrical 8 11-24-2008 01:00 PM
Wire gauge recommendations please Snowdog Electrical 33 08-22-2008 03:54 PM
Gauge Wire and Breaker Discrepancy broken_scout Electrical 26 12-22-2007 10:07 PM




Top of Page | View New Posts

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