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Discussion Starter · #1 ·
I am wiring a small garage off of a panel in another garage that has a 200 amp box. From the box in the large garage, to were I want the box in the small garage is 230 ft. I want to run direct burial cable. UF-B, I think, 8-3. I want 4 receptacles in the large garage and 4 shop lights. The tools I will be using are a circular saw, bench grinder, battery charger, small hand drills, and MAYBE put in a very small window air conditioner. I will never use more than one tool at a time.

My question is, will 8-3, or 6-3, be big enough? What kind of box do I need in the small garage? Links to products to purchase would be great. Also, how many amps will I carry with each cable size over that distance.
 

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I would put wires in oversized conduit rather than birect bury UF cable - don't have to trench as deeply and if you ever want larger capacity you can pull a larger wire.
 

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A "Handy Husband"
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I would bury 1" PVC conduit down 18" and pull in 4 runs of # 10 THWN (red, black, white and green). Run from a 2 pole 20 amp breaker in the larger garage. This is a MWBC (multiwire branch circuit) and will allow you to have 2 - 20 amp 120 volt circuits.

This is about the cheapest way to go initially but will allow you to upgrade in the future without re-digging.
 

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Discussion Starter · #6 ·
Good Gawddd.....went and bought 250ft of 6-3uf-b at a electrical supply place today and after tax it was over $900!!!!! Mannn, that stuff is high. The guy that will do the hooking it up told me to go buy a square d today??? Priced a trencher and it is $100 a day. Not bad, and, better than a shovel. Does it have to be 36" deep? From the voltage calculators online, 2 of them, I think I will have about 5% drop by the time I get to the garage. You have some suggestions, please let me know.
 

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Discussion Starter · #8 ·
Question....Have my 6-3 uf-b run from garage to shed, Keep in mind its a 220ft run. Is 5% voltage drop acceptable? If it is, as some say, I can run 50 amps out of the main box in the big garage. 40 amps will be like 3.5% drop.
 

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Lic Elect/Inspector/CPO
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Voltage drop cals can be done online. Here is the results of one, based #6, 1/2 circuit length, 240 volt single phase, 60 amp load.
The voltage drop percentage is acceptable.
Estimated Drop Volts Load At Circuit End Volts Voltage Drop Percentage
 
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