an electricians info
- Thread starter jk66
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ptonsparky
Tom
- Occupation
- EC - retired
What type of load are you serving? Motor? What size(s)? I would typically use 6 cu in conduit.
What comes first, the chicken or the egg?
Remember that the wire should be sided to carry the load and the rating of the breaker which feeds that wire is size to protect the wire with the understanding that the ampacity doesn't exceed the rating of the panel that's being feed.
Yes, you have a 60A sub panel, why did you select it? Is it because that is a standard panel? Is it a MLO which it would most likely be?
Did you select the panel based upon the anticipated continuous and non-continuous loads?
Then, are you trying to supply the panel at its maximum ampacity which you don't have to. There is no reason to feed a 60a rated panel should the maximum load be considerably less. If so the size of the wire feeding the panel should be based upon that load and a breaker which feeds the wire sized to project the wire.
You specifically chose #4 aluminum. Why? What is the NEC code reference that is how did you arrive at that size? Also, where is the cable originating? There must be a panel that you are feeding it with. Considering that the #4 Al wire that you selected, you must provide over current protection for that wire.
Remember that the wire should be sided to carry the load and the rating of the breaker which feeds that wire is size to protect the wire with the understanding that the ampacity doesn't exceed the rating of the panel that's being feed.
Yes, you have a 60A sub panel, why did you select it? Is it because that is a standard panel? Is it a MLO which it would most likely be?
Did you select the panel based upon the anticipated continuous and non-continuous loads?
Then, are you trying to supply the panel at its maximum ampacity which you don't have to. There is no reason to feed a 60a rated panel should the maximum load be considerably less. If so the size of the wire feeding the panel should be based upon that load and a breaker which feeds the wire sized to project the wire.
You specifically chose #4 aluminum. Why? What is the NEC code reference that is how did you arrive at that size? Also, where is the cable originating? There must be a panel that you are feeding it with. Considering that the #4 Al wire that you selected, you must provide over current protection for that wire.
cadpoint
Senior Member
- Location
- Durham, NC
One should address all the requirments of any circuited service.
This is a standing Code requirement!
How one meets those requirements can well be get varied but in the end, it'll only most times be just the minimal for an application...
The code book Index can be your friend (If you think link the NEC)!
This is a standing Code requirement!
How one meets those requirements can well be get varied but in the end, it'll only most times be just the minimal for an application...
The code book Index can be your friend (If you think link the NEC)!
thanks to all the replies and once again every answer that one receives cannot be in plain english, like the code book! haha things would be much easier if the code book was in plain english and not such a pain to look for answers. i.e. if i have a 60 amp panel table 310 should plainly say what size connductors i need not paging through the book 8 different places
hmspe
Senior Member
- Location
- Temple, TX
- Occupation
- PE
Have you looked at NEC 110.14(C)? Are you sure you can use the 75degC column value?
ptonsparky
Tom
- Occupation
- EC - retired
What code book do you have?
I use 60c for loads under 100 amp. (non-motor)
Visit 240.6(A)
Then refer to 240.4(B)
You still need to determine what load you will have in this garage. For all we know it is 10,000 sq ft.
You can use a #6 AL to feed a 60 A rated panel, but what is your expected load and what size over current protection are you using ahead of it? Reference post with Chicken or Egg.
I've never seen a 60 amp subpanel. Most panels seem to be rated at 70, 125, and 200 amps. When someone says to me a "60 amp subpanel", I'm assuming they want a 60A feeder to a subpanel. If you want a 60A feeder, and can use 75C terminations, then you need #4 aluminum. If you can only use 60C terminations, you are still fine with the same wire but your calculated load must be limited to 55A. If people aren't doing calculations (e.g. typical residential install) then having an ampacity equal or greater than the breaker rating is a good design (use the 65A wire).
I don't know how you could ever use #6 al to feed a "60 amp subpanel". It is limited to a 40A or 50A breaker depending on termination temperatures, and perhaps even less if there are deratings to apply.
The code book cannot be as you wish because wire ampacities don't land on nice 40/50/60 amp boundaries. They are what they are, and then when you add derating factors they get even more off from standard breaker sizes. The NEC tables can't know your ambient temperatures, bundling, etc to give you a simple answer.
I don't know how you could ever use #6 al to feed a "60 amp subpanel". It is limited to a 40A or 50A breaker depending on termination temperatures, and perhaps even less if there are deratings to apply.
The code book cannot be as you wish because wire ampacities don't land on nice 40/50/60 amp boundaries. They are what they are, and then when you add derating factors they get even more off from standard breaker sizes. The NEC tables can't know your ambient temperatures, bundling, etc to give you a simple answer.
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