A novice rewiring 1940's build house

Reply

  #1  
Old 02-21-11, 10:29 PM
Member
Thread Starter
Join Date: Feb 2011
Location: usa
Posts: 3
A novice rewiring 1940's build house

The house I am rewiring was built in 1940's and came with one 30 Amp
breaker in the sub panel. Since then, the local electric company upgraded the main panel to 240v; the house still had 30 Amp circuit breaker. Now I have upgraded the sub panel to 125 Amp sub panel and rewired the house
with Romex 12/2 NMB wires.

My question is this - to rewire from 220 v Main Panel to sub panel,
what are my choices besides Romex SER #1 (rated 130 Amp) ?
Can I use Romex SER #2 (rated 100 Amp) ?
My heater, dryer and stove is all gas, so don't need 30 Amp breakers.

Thanks

HP
 

Last edited by hominpaik; 02-21-11 at 10:32 PM. Reason: typo
Sponsored Links
  #2  
Old 02-22-11, 06:05 AM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 14,594
Does the subpanel have all the circuits for the house in it? Is there a main breaker somewhere?

What is commonly called Romex is technically type NM-B cable. It is not the same as type SE cable. Both can only be used at the 60 degree rating so your ampacities are incorrect. We would also need to know the conductor material.
 
  #3  
Old 02-22-11, 08:21 PM
Member
Thread Starter
Join Date: Feb 2011
Location: usa
Posts: 3
Thanks pcboss for replying.
Yes the sub panel have all the circuits for the house. The main
breaker is outside the house, next to the SDGE meter panel, but
I was told to bring in the shut off breaker (100 Amp) to the sub panel.

I saw Romex 2-3 NMB at Home Depot, but it's rated only 95 AMPS;
I spoke to a commercial electrical supplier, and she said I should go with
Romex 1-2 SER (copper), rated upto 130 AMP, since my sub panel is
125 AMP.

BTW, what do you mean by "60 degree rating" ???

Am I making any sense yet ?
I am so embarassed to sound so dumb!
 
  #4  
Old 02-22-11, 09:00 PM
ray2047's Avatar
Group Moderator
Join Date: Mar 2006
Location: USA
Posts: 33,058
So the 30 amp panel no longer exists, correct? It was replaced with the 125a panel Correct?

Ok, how close is the main panel to the subpanel? If 5'* or less I'd just run conduit on the outside of the house and use three individual 1/0 THWN individual conductors and one #6 for ground. Sizes refer to copper.

*If your OK with appearance the conduit could be run as far as needed on the outside wall.
 
  #5  
Old 02-24-11, 07:50 AM
Member
Thread Starter
Join Date: Feb 2011
Location: usa
Posts: 3
Ray2047, thanks for replying.

Yes you are correct that the 30 amp sub panels has been replaced by 125 amp sub panels
(duplex).

According to a electrician, even with 125 amp sub panel, I can go with 100 amp breaker/100 amp rated Romex #2 for each of the duplex, since that should be plenty. Of course they would be run through the attic/crawl space.

Thanks

What are your thoughts?
 
  #6  
Old 02-24-11, 09:59 AM
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,515
Originally Posted by hominpaik View Post
According to a electrician, even with 125 amp sub panel, I can go with 100 amp breaker/100 amp rated Romex #2 for each of the duplex, since that should be plenty. Of course they would be run through the attic/crawl space.
That is correct. The copper #2-3/g NM-B romex should be protected in the attic by running along a framing member or 2x4 running board. You could also use #2 copper SER (four conductor).
 
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