Feeder line sizes

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Old 06-28-17, 11:38 PM
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Feeder line sizes

So from my meter/main-breaker (which comes in at a detached garage) I need to run 140 feet underground in conduit to get to the sub-panel at my house.

I'm planning to use aluminum (I'm poor, OK? ) and it's a 200 amp, single phase service.

My primitive calculations say #4/0 for both hots, #2/0 for neutral, and #6 for the ground.

Does that spec out? Or do I need to go fatter?
 
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Old 06-29-17, 01:16 AM
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Based on the distance..... you should experience acceptable sag up to 150A.

The 4/0 AL is rated for 205A.
2/0 AL for neutral is correct.
#4 AL for 200A service ground.

3" conduit would be a good choice.
 
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Old 06-29-17, 10:48 AM
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"....acceptable sag up to 150A."

Is that something you would be OK with? The house includes a small rental unit with its own appliances. Most of the appliances in both the main house and the rental run on gas (dryers, stoves, etc) so it seems like the chances of ever hitting above that 150 mark would be remote. But it is technically two households running on those feeders.
 
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Old 06-29-17, 11:28 AM
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What is the sub panel for, are you remodeling or something? Depending on what all this is for you might not need as much as you think when it comes to amps. You have many options and they can mean big differences when it comes down to time money and headache. Also it's kind of odd having a main service at a garage then back feeding the house. It's legal but kind of uncommon so are these buildings existing or new.
 
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Old 06-29-17, 11:36 AM
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Gas is a plus and keeps the high electric demands down.

For that application the 4/0's should be ok.
 
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Old 06-29-17, 12:06 PM
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All the buildings are existing. The power drop has always come in at the detached garage, I assume because it's the closest building on the property to where the distribution lines run (we're pretty rural). The feeder lines from our side of the meter/main disconnect at the garage then run up to a separate mast, and then overhead (and through some trees) to the house. It's always been a bit hokey. Needless to say, getting those feeder lines underground has many advantages.
 
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Old 06-29-17, 02:52 PM
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If you already have power run overhead and it's working ok.... what size is that wire ?
If you're running larger then there should be no issues at all.
 
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