Just want to be sure I have Amperacity right...


NMC is rated for its 140 degree amperacity, regardless that it is actually 190 degrees insulation; so #8 copper used to feed a subpanel needs a 40a breaker. #6 can have a 60a breaker because it is 55a and rounded up to the nearest size.
I want 50a capacity, so I need #6.
Is this correct? Just want to be sure.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

For the benefit of those who may not know... wire and cable are temperature-rated in degrees CELSIUS. NM is rated at 60 degrees C. Toller is referring to the Fahrenheit equivalent.
BTW, it's "ampacity".

You sure about that? (90 C = 194 F, BTW)

Correct.
Correct.
Yes, it is. Make sure you use a 4-wire cable, and keep the neutral and ground *separated* in the subpanel.
--
Regards,
Doug Miller (alphageek at milmac dot com)
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Toller wrote:

Yes, but from memory, you also could use #6 aluminum SE (SER) cable, or #8 THHN wire in conduit (also depends on the temperature rating of the terminals)
Best regards, Bob
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.