service question

Status
Not open for further replies.
S

solo618

Member
Location
Orange County, N.Y.
This may be a really stupid question but to be honest i've been in the business for 15 years and i learned my trade in a big east coast city,so most of my experience is in commercial, industrial and transit work.That being said,now to my question,is it code compliant to use aluminum wire to feed a sub panel for a one family dwelling.Now if that subpanel happens to be 100amps,normally at work we always use #2 wire copper,but looking at 310.15(b)(6) it says #2 copper is good for 125 amps and #4 for 100amps. Can i use that#4 wire to feed my 100amp subpanel ? Sorry i guess that was two questions. My bad.
 
and per NEC you can use the appropriately sized conductor, AL or Cu.
There may be some local ordinances that prohibit it (AL) , but I personally know of none.
 
What I normally use is #2/3 SER and use a 90amp breaker for my sub-panels, I've yet to need a 100 amps for a subpanel, I just use the main panel for my larger loads...
 
Solo,
First you must determine if 310.15(B)(6) is useable in your situation as others have indicated. Unless this feeder carries the entire load for the dwelling you will need to use 310.16. Then refer to 110.14 for the temperature limitations which will require that you use the ampacity at 60 or 75 degrees, not 90 degrees.
 
service question

Thank you for the quick responses,but this was just an idea i had kicking around in my head and i asked the guys at work and it seemed that none of them have even opened a code book at all. So i figured i'd throw it at you guys in here because i can tell there are people who really know what they are talking about.There is one other thing that has me confused now.It was mentioned if the subpanel would be holding the load for the entire dwelling.How could this be possible? Like i said this isn't a real situation but for argument sake lets say it is and the subpanel would be fed from a 200 amp panel which has up to now the entire load of the dwelling.Now i use a 2 pole 100 amp breaker and feed the subpanel.how could this subpanel carry the load for the dwelling like was said in the other post? Please explain because i would appreciate any info offered .
 
solo618 said:
It was mentioned if the subpanel would be holding the load for the entire dwelling.How could this be possible? Like i said this isn't a real situation but for argument sake lets say it is and the subpanel would be fed from a 200 amp panel which has up to now the entire load of the dwelling.Now i use a 2 pole 100 amp breaker and feed the subpanel.how could this subpanel carry the load for the dwelling like was said in the other post? Please explain because i would appreciate any info offered .
Click to expand...

The sub panel in your example won't carry the full load. What this is intended for is multi-family dwellings, say an apartment building. Each feeder to the individual units could be sized by 310.15(B)(6)

Aluminum wire would be fine for your feeder, as long as the breaker and/or terminals are rated for it. Check with your local jurisdiction, though. Some around here restrict AL to #4 or larger, some #6 or larger.
 
solo618 said:
Thank you for the quick responses,but this was just an idea i had kicking around in my head and i asked the guys at work and it seemed that none of them have even opened a code book at all. So i figured i'd throw it at you guys in here because i can tell there are people who really know what they are talking about.There is one other thing that has me confused now.It was mentioned if the subpanel would be holding the load for the entire dwelling.How could this be possible? Like i said this isn't a real situation but for argument sake lets say it is and the subpanel would be fed from a 200 amp panel which has up to now the entire load of the dwelling.Now i use a 2 pole 100 amp breaker and feed the subpanel.how could this subpanel carry the load for the dwelling like was said in the other post? Please explain because i would appreciate any info offered .
Click to expand...

If you had say a disconnect next to a meter and then a feeder to a panel, that panel would end up being a subpanel. That feeder would be carrying the entire load of the dwelling. A feeder from a 200 amp panel feeding a 100 amp subpanel would not be feeding the entire load.
 
Status
Not open for further replies.
Top