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 05-14-2011, 03:06 PM   #1
Member
 
Join Date: Apr 2007
Posts: 2,266
Share |
Question

using bigger (legacy) wire for smaller amperage


i replaced my electric dryer for a gas one and now i have a vacant 30A circuit with 10/3 gauge cable going through the house.

at the same time, i am putting up a powder room where the old dryer used to be and there will be a bathroom above as well.

i wanted to have a 20A circuit going to the powder room and the bathroom. i was wondering whether it is OK for me to reuse the legacy 10/3 cable if i do replace the 30 for a 20A breaker at the panel. i would do it just to the powder room and then i would, of course, go with a 12 gauge... just so i don't have to pull the old cable out and replace it with the adequate 12 gauge. i'm guessing smaller amperage should be OK going through fatter wire. obviously, i there would be an unused wire in the cable in this scenario but i don't care.

amakarevic is offline   Reply With Quote
Old 05-14-2011, 04:56 PM   #2
Electrician
 
SD515's Avatar
 
Join Date: Aug 2008
Location: Near Jackson Michigan Area
Posts: 1,450
Default

using bigger (legacy) wire for smaller amperage


The short answer is yes. The ampacities listed in the code are the minimum. You can always use a larger wire than necessary as long as the terminals will accept said gauge.

__________________
Kyle

Just because you can, doesn't always mean you should
SD515 is offline   Reply With Quote
The Following User Says Thank You to SD515 For This Useful Post:
amakarevic (05-14-2011)
Old 05-14-2011, 04:59 PM   #3
Member
 
Join Date: Apr 2007
Posts: 2,266
Smile

using bigger (legacy) wire for smaller amperage


sweeeeeeeet !!!! thanks ... that saves me a lot of time and $$
amakarevic is offline   Reply With Quote
Old 05-14-2011, 07:19 PM   #4
DIY'er
 
jamiedolan's Avatar
 
Join Date: Sep 2008
Location: Neenah, Wisconsin, USA
Posts: 2,032
Blog Entries: 2
Default

using bigger (legacy) wire for smaller amperage


Quote:
Originally Posted by amakarevic View Post
i replaced my electric dryer for a gas one and now i have a vacant 30A circuit with 10/3 gauge cable going through the house.

at the same time, i am putting up a powder room where the old dryer used to be and there will be a bathroom above as well.

i wanted to have a 20A circuit going to the powder room and the bathroom. i was wondering whether it is OK for me to reuse the legacy 10/3 cable if i do replace the 30 for a 20A breaker at the panel. i would do it just to the powder room and then i would, of course, go with a 12 gauge... just so i don't have to pull the old cable out and replace it with the adequate 12 gauge. i'm guessing smaller amperage should be OK going through fatter wire. obviously, i there would be an unused wire in the cable in this scenario but i don't care.
Will this be feeding 2 bathrooms?
__________________
Jamie Dolan - Neenah, WI
Jamie Dolan Paw Dogs
Need Help Uploading Photos? Click here.
jamiedolan is offline   Reply With Quote
Old 05-14-2011, 08:12 PM   #5
Member
 
Join Date: Sep 2008
Location: SoCal
Posts: 1,794
Default

using bigger (legacy) wire for smaller amperage


Suggest you tag and annotate the wire in the panel so the next guy does not see the larger wire and think a larger breaker is ok.
vsheetz is offline   Reply With Quote
Old 05-15-2011, 07:06 AM   #6
Electrician
 
SD515's Avatar
 
Join Date: Aug 2008
Location: Near Jackson Michigan Area
Posts: 1,450
Default

using bigger (legacy) wire for smaller amperage


I might have jumped the gun...is that cable 10/3 with ground? (black, red, white, bare)?

Assuming it is....
As vsheetz suggested, it's a good idea to tag the 10/3 in the panel that it's a 20A circuit. You can use a 20A/2-pole breaker, have one 'hot' feed the powder room and feed the bath with the other, sharing the neutral. Do you know the rules about feeding a bathroom? If you cap off one of the wires in the 10/3, you'd probably have to run another homerun from the panel to feed the bath receptacle(s).
__________________
Kyle

Just because you can, doesn't always mean you should
SD515 is offline   Reply With Quote
The Following User Says Thank You to SD515 For This Useful Post:
jamiedolan (05-15-2011)
Old 05-15-2011, 02:37 PM   #7
Member
 
Join Date: Apr 2007
Posts: 2,266
Default

using bigger (legacy) wire for smaller amperage


Quote:
Originally Posted by jamiedolan View Post
Will this be feeding 2 bathrooms?
a powder room and a bathroom
amakarevic is offline   Reply With Quote
Old 05-15-2011, 02:52 PM   #8
DIY'er
 
jamiedolan's Avatar
 
Join Date: Sep 2008
Location: Neenah, Wisconsin, USA
Posts: 2,032
Blog Entries: 2
Default

using bigger (legacy) wire for smaller amperage


Quote:
Originally Posted by amakarevic View Post
a powder room and a bathroom
Are you aware of the codes relating to wiring bathrooms?
__________________
Jamie Dolan - Neenah, WI
Jamie Dolan Paw Dogs
Need Help Uploading Photos? Click here.
jamiedolan is offline   Reply With Quote
Old 05-15-2011, 03:23 PM   #9
Member
 
Join Date: Apr 2007
Posts: 2,266
Default

using bigger (legacy) wire for smaller amperage


Quote:
Originally Posted by jamiedolan View Post
Are you aware of the codes relating to wiring bathrooms?
i think you have to have a dedicated circuit for a bathroom. but i simply don't have any more slots available at my panel and it had a shared circuit before.
amakarevic is offline   Reply With Quote
Old 05-15-2011, 03:42 PM   #10
Member
 
Join Date: Apr 2007
Posts: 2,266
Question

using bigger (legacy) wire for smaller amperage


alternatively, i can use the last remaining slot for a dedicated circuit to the bathroom but then i would need to branch out a non-bathroom circuit (mostly used for lighting) to go into the powder room. do you think that would be better?

thanks
amakarevic is offline   Reply With Quote
Old 05-15-2011, 04:23 PM   #11
DIY'er
 
jamiedolan's Avatar
 
Join Date: Sep 2008
Location: Neenah, Wisconsin, USA
Posts: 2,032
Blog Entries: 2
Default

using bigger (legacy) wire for smaller amperage


Quote:
Originally Posted by amakarevic View Post
alternatively, i can use the last remaining slot for a dedicated circuit to the bathroom but then i would need to branch out a non-bathroom circuit (mostly used for lighting) to go into the powder room. do you think that would be better?

thanks
You can put all the outlets from both bathrooms on one 20A circuit. However; other items such as lights and fans need to be put onto some other circuit. Their load is likely low, so you might be able to sneak them on with something else.

Jamie
__________________
Jamie Dolan - Neenah, WI
Jamie Dolan Paw Dogs
Need Help Uploading Photos? Click here.
jamiedolan is offline   Reply With Quote
Old 05-15-2011, 04:51 PM   #12
Member
 
Join Date: Apr 2007
Posts: 2,266
Default

using bigger (legacy) wire for smaller amperage


Quote:
Originally Posted by jamiedolan View Post
You can put all the outlets from both bathrooms on one 20A circuit. However; other items such as lights and fans need to be put onto some other circuit. Their load is likely low, so you might be able to sneak them on with something else.
do you know the reasoning behind that?

thanks
amakarevic is offline   Reply With Quote
Old 05-15-2011, 04:55 PM   #13
DIY'er
 
jamiedolan's Avatar
 
Join Date: Sep 2008
Location: Neenah, Wisconsin, USA
Posts: 2,032
Blog Entries: 2
Default

using bigger (legacy) wire for smaller amperage


Quote:
Originally Posted by amakarevic View Post
do you know the reasoning behind that?

thanks
Not really. But you can either have the outlets only from the 2 baths on one circuit and the lights / fans on a different (any shared circuit) or you can have a dedicated circuit for each bathroom.

It's often hard to know the exact reasoning behind many of the NEC rules.
__________________
Jamie Dolan - Neenah, WI
Jamie Dolan Paw Dogs
Need Help Uploading Photos? Click here.
jamiedolan is offline   Reply With Quote
Old 05-15-2011, 04:58 PM   #14
Electrician
 
SD515's Avatar
 
Join Date: Aug 2008
Location: Near Jackson Michigan Area
Posts: 1,450
Default

using bigger (legacy) wire for smaller amperage


A circuit for a bathroom can either (1) supply everything in that bath only, as long as nothing fastened in place, other than lighting, exceeds 50% of the circuit rating (10 amps) (like a heater for example), or (2) can supply receptacles in that and other bathrooms, but only bathrooms and only receptacles.
__________________
Kyle

Just because you can, doesn't always mean you should
SD515 is offline   Reply With Quote
The Following 2 Users Say Thank You to SD515 For This Useful Post:
amakarevic (05-15-2011), jamiedolan (05-15-2011)
Old 05-15-2011, 05:06 PM   #15
Member
 
Join Date: Apr 2007
Posts: 2,266
Default

using bigger (legacy) wire for smaller amperage


Quote:
Originally Posted by SD515 View Post
A circuit for a bathroom can either (1) supply everything in that bath only, as long as nothing fastened in place, other than lighting, exceeds 50% of the circuit rating (10 amps) (like a heater for example), or (2) can supply receptacles in that and other bathrooms, but only bathrooms and only receptacles.
thanks but that sounds really more like a code excerpt rather than an actual scientific backing thereof

amakarevic 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
What type wire to use from transfer switch to outdoor outlet brjl Electrical 32 11-20-2013 08:36 AM
Proper Use of Green Wire Nuts HooKooDooKu Electrical 16 06-29-2012 06:41 PM
Fanimation ceiling fan question: no blue wire from ceiling camrn2006 Electrical 8 03-07-2010 12:19 AM
HALP! Master/Remote Dimmer troubles! Confuserated Electrical 9 02-12-2010 03:30 PM
Old house, new light fixture, too many wires Persephonee Electrical 3 01-15-2007 08:58 AM




Top of Page | View New Posts

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