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First of all is a 100 amp panel sufficient? Will only be lighting and general outlets because it is going to be a horse barn. No heavy equipment

Secondly just want to make sure my math is correct. I believe I can use 1/0 copper in an 1.5 inch schedule 40 pvc

Well pump will be 240 Located in south Florida

Hugh Von Minden
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Your copper is likely significantly overkill unless you're running this a very, very long distance. For reasonable distances 1/0 THWN will be good for at least 150A. Do consider using what is known as 'mobile home feeder'. It's aluminum, much cheaper per foot, can be direct buried in some circumstances, and widely available for a fraction of the cost per foot of copper cable. If you end up only needing 90A you can probably use 2-2-4-6 which is so widely used that it's downright cheap in most places, the cost of a single strand of #1 THWN. Even 2-0/2-0/2-0/1 comes in at less per foot than two strands of the #1 THWN you need to run the same current.

As to 100A being sufficient, the only way to answer that is with a load calculation. We don't have sufficient information to help there, as we don't know your loads. My 'gut check' says a barn fed with 100A should be fine because I've seen plenty of them fed with 40A and working just fine, but that doesn't actually help if you have specific plans that need more current.

KMJ
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  • Aluminum wire - no reason whatsoever for copper when it comes to feeders.
  • As noted in another answer, 2 AWG (2/2/24) aluminum is often priced very competitively, and that is enough for up to 90A.
  • BIG panel. The panel has to be rated at least as high as the feed breaker. Beyond that, there is no particular requirement. So a 90A feed (or even a 60A feed) is perfectly fine with a 100A panel. But you do not need to stop there. A 200A "main" panel is perfectly fine, and in fact often a 200A panel that comes with free "bonus breakers" can be about the same price as a much smaller 100A subpanel.
  • There are two key differences between a "main" panel and a "sub" panel: Main breaker and grounding. A "main" breaker is not required, per se, in a subpanel. However, when that subpanel is in a separate building from the main panel, it needs a disconnect. A "main" breaker works perfectly fine as a disconnect and saves having to add another box just to have a disconnect. As far as grounding: many, but not all, "main" panels do not include a ground bar, so you may need to add one, and you need to make sure that neutral is not bonded to ground. Other than that, a "main" panel is 100% fine as a subpanel.
  • 200A panels tend to be larger than 100A panels. Larger panels have the advantage of lots of breaker spaces. You probably only need ~ 4 breaker spaces now. But someday if you decide to do more things in the barn you might need many more. Empty spaces cost very little. Replacing a panel costs in time and materials.
  • Load Calculation - With your current (pun intended) plans, I'm not worried about a Load Calculation for the barn feed breaker. But I am concerned about your overall service. You should do an NEC Load Calculation to make sure you can spare 40A+ from your service/main panel. If your service doesn't have the capacity then you either need a heavy-up or some changes to other loads or load shedding.
manassehkatz-Moving 2 Codidact
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First of all is a 100 amp panel sufficient?

Usually fine, yes.

Will only be lighting and general outlets because it is going to be a horse barn.

Assuming LED lights, 20 amps would suffice in all honesty.

No heavy equipment.

You could comfortably run most power tools and a shop-vac simultaneously without tripping a 20 amp breaker. I do it all the time with my miter saw + show-vac or table saw + show-vac.

Secondly just want to make sure my math is correct. I believe I can use 1/0 copper in an 1.5 inch schedule 40 pvc.

I don't know electrical math once you get into those sizes.

Consider aluminum like the other posts suggested and consider running a 200 amp wire instead just in case you find that a 100 amp panel is insufficient in the future.

Well pump will be 240 Located in south Florida

These usually require 240v, so you lied about "lighting and general outlets"?

You'd want at minimum whatever the well pump draws plus 20 amps.

MonkeyZeus
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