Go Back   InterNACHI Inspection Forum > Specific Inspection Topics > Electrical Inspections

Notices

Electrical Inspections Contains discussions about electrical systems. This includes receptacles, panels, wiring, etc.

Reply
 
LinkBack Thread Tools
  #1  
Old 3/2/12, 5:51 PM
Wayne B. Wilson's Avatar
Wayne B. Wilson Wayne B. Wilson is online now
InterNACHI Member
 
Join Date: Aug 2008
Location: Powell, Tn
Posts: 12,373
Default #4 for 100 amp sub panel ?

Got a question
225 amp main panel
Sub Panel 100 amp breaker is a number 4 copper ok to use for a feeder?
seems to a lot of confusion over this one i marked for being under sized and refereed it to a electrician, builder refused and sent it was Ok under
Article 310-15-B6 NEC #4 awg
Buyer want it changed on his report



Wayne Wilson
East TN Home Inspections LLC
Knoxville, Oak Ridge, Maryville, Clinton, Farragut, Lenoir City, Pigeon Forge, Sevierville and all the surrounding areas.
865-256-1490

http://site.myhomeinspection.net

Reply With Quote
Need a home inspection in Minnesota? Check out InterNACHI's listing of Minnesota certified home inspectors. Or, find a home inspector anywhere in the world with our inspection search engine.
  #2  
Old 3/2/12, 6:18 PM
Robert Meier's Avatar
Robert Meier Robert Meier is offline
Active Poster
 
Join Date: Feb 2010
Location: New Jersey
Posts: 2,080
Please Note: Robert Meier is a non-member guest and is in no way affiliated with InterNACHI or its members.
Default Re: #4 for 100 amp sub panel ?

No good. #4 THHN is only rated for 85 amps at 75° C. This would be for MC cable or conductors in a raceway. SE cable in thermal insulation or NM cable would be rated at 60° C which has an ampacity of 70 amps.

Last edited by Robert Meier; 3/2/12 at 6:33 PM.. Reason: Clarification
Reply With Quote
  #3  
Old 3/2/12, 6:38 PM
KEVIN WOOD, CMI's Avatar
KEVIN WOOD, CMI KEVIN WOOD, CMI is online now
InterNACHI Member
 
Join Date: Mar 2006
Location: Sault Ste Marie ON
Posts: 11,661
Default Re: #4 for 100 amp sub panel ?

What the InterNachi says is #3 AWG for a remote distribution panel.
19th edition of Canadian Electrical says #3 RX 90XLPE copper
Reply With Quote
  #4  
Old 3/2/12, 6:50 PM
Wayne B. Wilson's Avatar
Wayne B. Wilson Wayne B. Wilson is online now
InterNACHI Member
 
Join Date: Aug 2008
Location: Powell, Tn
Posts: 12,373
Default Re: #4 for 100 amp sub panel ?

I still stayed with my statement and didn't change the report. Seems to be a lot of confusion on this topic 600.000 Plus home 5 feet of wire Who knows



Wayne Wilson
East TN Home Inspections LLC
Knoxville, Oak Ridge, Maryville, Clinton, Farragut, Lenoir City, Pigeon Forge, Sevierville and all the surrounding areas.
865-256-1490

http://site.myhomeinspection.net

Reply With Quote
  #5  
Old 3/2/12, 7:09 PM
KEVIN WOOD, CMI's Avatar
KEVIN WOOD, CMI KEVIN WOOD, CMI is online now
InterNACHI Member
 
Join Date: Mar 2006
Location: Sault Ste Marie ON
Posts: 11,661
Default Re: #4 for 100 amp sub panel ?

Mike Holt Knows and agrees with the #3 and #4 is only good for 70Amps, so Robert is right also.
Reply With Quote
  #6  
Old 3/2/12, 7:43 PM
Wayne B. Wilson's Avatar
Wayne B. Wilson Wayne B. Wilson is online now
InterNACHI Member
 
Join Date: Aug 2008
Location: Powell, Tn
Posts: 12,373
Default Re: #4 for 100 amp sub panel ?

Thanks guys, I am glad i stuck to my guns lolol



Wayne Wilson
East TN Home Inspections LLC
Knoxville, Oak Ridge, Maryville, Clinton, Farragut, Lenoir City, Pigeon Forge, Sevierville and all the surrounding areas.
865-256-1490

http://site.myhomeinspection.net

Reply With Quote
  #7  
Old 3/2/12, 8:27 PM
Robert Meier's Avatar
Robert Meier Robert Meier is offline
Active Poster
 
Join Date: Feb 2010
Location: New Jersey
Posts: 2,080
Please Note: Robert Meier is a non-member guest and is in no way affiliated with InterNACHI or its members.
Default Re: #4 for 100 amp sub panel ?

Depending on the connected load of the subpanel you might be able to change the OCPD to a smaller size without changing the conductors.
Reply With Quote
  #8  
Old 3/2/12, 8:29 PM
Wayne B. Wilson's Avatar
Wayne B. Wilson Wayne B. Wilson is online now
InterNACHI Member
 
Join Date: Aug 2008
Location: Powell, Tn
Posts: 12,373
Default Re: #4 for 100 amp sub panel ?

Thanks Robert, I told them that but i left it up to the Electrician .



Wayne Wilson
East TN Home Inspections LLC
Knoxville, Oak Ridge, Maryville, Clinton, Farragut, Lenoir City, Pigeon Forge, Sevierville and all the surrounding areas.
865-256-1490

http://site.myhomeinspection.net

Reply With Quote
  #9  
Old 3/3/12, 9:01 AM
Jim Port Jim Port is offline
Unmoderated Guest
 
Join Date: Jul 2007
Location: Maryland
Posts: 1,458
Please Note: Jim Port is a non-member guest and is in no way affiliated with InterNACHI or its members.
Default Re: #4 for 100 amp sub panel ?

There are two charts for wire sizing, one was for when the entire load of the dwelling was served and the other one that was for the other sizings. Many did not distinguish the difference.
Reply With Quote
  #10  
Old 3/3/12, 9:52 AM
Bruce M. Graham Bruce M. Graham is offline
InterNACHI Member
 
Join Date: Sep 2005
Location: Gainesville, FL
Posts: 2,444
Default Re: #4 for 100 amp sub panel ?

The breaker still has to protect the conductor.



http://www.nachi.org/forum/image.php?type=sigpic&userid=6376&dateline=1330979  258
Professional Inspection Services, LLC dba
1st Inspection Services
Bruce M. Graham III
Gainesville, FL 32608
352 871 8989
Florida Licensed Home Inspector #HI10
Certified Level II Infrared Thermographer
Radon Measurment Technician # R2279
NACHI05091592
ICC 5268478
www.1stinspectionsfl.com
www.bungalowstomansions.com
Reply With Quote
  #11  
Old 3/3/12, 10:20 AM
Robert Meier's Avatar
Robert Meier Robert Meier is offline
Active Poster
 
Join Date: Feb 2010
Location: New Jersey
Posts: 2,080
Please Note: Robert Meier is a non-member guest and is in no way affiliated with InterNACHI or its members.
Default Re: #4 for 100 amp sub panel ?

Quote:
Originally Posted by wwilson3 View Post
Got a question
225 amp main panel
Sub Panel 100 amp breaker is a number 4 copper ok to use for a feeder?
seems to a lot of confusion over this one i marked for being under sized and refereed it to a electrician, builder refused and sent it was Ok under
Article 310-15-B6 NEC #4 awg

Buyer want it changed on his report

Seems like the builder has no idea how to read the codebook. What is the voltage system that this is being used on? That table is very specific in that it is only used for certain dwellings and 1Ř, 120/240 volt systems. Considering you mentioned a 225 amp main panel I would guess that neither of those criteria apply.
Reply With Quote
  #12  
Old 3/3/12, 11:26 PM
Paul W. Abernathy, CMI's Avatar
Paul W. Abernathy, CMI Paul W. Abernathy, CMI is offline
InterNACHI Member
 
Join Date: Sep 2005
Location: McKinney, TX
Posts: 8,664
Send a message via Skype™ to pabernathy
Default Re: #4 for 100 amp sub panel ?

Remember....That smaller table [310.15(B)(7)] is only good if you are dealing with 120/240 volt, single phase dwelling service conductors, service- lateral conductors and main power feeders and in your example you have none of those. The client would have to use the traditional ampacity ratings in accordance with Section 310.15(B)(16) to be compliant.



Paul W. Abernathy
Manager, Electrical Codes & Standards
Encore Wire Corporation

“Promise me you'll always remember: You're braver than you believe, and stronger than you seem, and smarter than you think.”

Disclaimer - All my posts on this forum are of my own personal opinion and in no way represent the opinions of Encore Wire, or other associations, organizations or affiliations.
Reply With Quote
  #13  
Old 3/4/12, 8:16 AM
Wayne B. Wilson's Avatar
Wayne B. Wilson Wayne B. Wilson is online now
InterNACHI Member
 
Join Date: Aug 2008
Location: Powell, Tn
Posts: 12,373
Default Re: #4 for 100 amp sub panel ?

Good lord we are still going around on this . I referred to a electrician, Builder is saying i am wrong and wants it changed in my report. According to this Paul #4 is Under sized Am I right?



Wayne Wilson
East TN Home Inspections LLC
Knoxville, Oak Ridge, Maryville, Clinton, Farragut, Lenoir City, Pigeon Forge, Sevierville and all the surrounding areas.
865-256-1490

http://site.myhomeinspection.net

Reply With Quote
Need a home inspection in Minnesota? Check out InterNACHI's listing of Minnesota certified home inspectors. Or, find a home inspector anywhere in the world with our inspection search engine.
  #14  
Old 3/4/12, 8:28 AM
Robert Meier's Avatar
Robert Meier Robert Meier is offline
Active Poster
 
Join Date: Feb 2010
Location: New Jersey
Posts: 2,080
Please Note: Robert Meier is a non-member guest and is in no way affiliated with InterNACHI or its members.
Default Re: #4 for 100 amp sub panel ?

Quote:
Originally Posted by wwilson3 View Post
Good lord we are still going around on this . I referred to a electrician, Builder is saying i am wrong and wants it changed in my report. According to this Paul #4 is Under sized Am I right?
Let's start with the wiring method, is it conductors in a raceway, SE cable, MC cable, NM cable? The differences were listed in post #2.
Reply With Quote
  #15  
Old 3/4/12, 9:08 AM
Wayne B. Wilson's Avatar
Wayne B. Wilson Wayne B. Wilson is online now
InterNACHI Member
 
Join Date: Aug 2008
Location: Powell, Tn
Posts: 12,373
Default Re: #4 for 100 amp sub panel ?

Here is the panel in question
Main 225
Home built in 2007 ( never lived in)
sub 100 amp
one breaker 60 amp
rest 20 amp
Sub panel is right beside main wire is run through conduit
I am trying to up load a picture but nothing happens
I try later



Wayne Wilson
East TN Home Inspections LLC
Knoxville, Oak Ridge, Maryville, Clinton, Farragut, Lenoir City, Pigeon Forge, Sevierville and all the surrounding areas.
865-256-1490

http://site.myhomeinspection.net

Reply With Quote
Reply

Thread Tools

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 On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Help proof the safety section on inspecting electrical panels: read here kshepard Electrical Inspections 58 6/8/14 4:52 PM
National Electrical Code Information and Discussion jtedesco1 Electrical Inspections 50 6/15/10 7:28 PM
Electric Panel dmozzillo Electrical Inspections 26 1/26/09 1:18 PM
Bad electrical problem Pest Guy Electrical Inspections 4 1/20/06 9:26 PM

All times are GMT -4. The time now is 9:51 AM.
no new posts