Electrician advice needed

[Bazoo]

I want to run an extention cord 250' from the house to my building. I'll only run one tool at a time plus a light and a box fan. 15 amp saw so say right on 20 amps. I can go without the light and fan if need be. Got a 20 amp circuit in the house I want to plug it into. I'm thinkng I'll buy a spool of Romex. I'm brainstorming it right now.

So, what size of wire would suffice?

Thanks, Bazoo

[jonp]

15 amps = 14/2
20 amps = 12/2
30 amps = 10/2

When in doubt use the next bigger wire. Match the wire size to the circuit breaker. You can use 12/2 wire with a 15 amp breaker but never 14/2 with a 20 amp breaker. If your running that far with a wire I'd drop another size in line from 12 to 10. When in doubt, go bigger. Remember, wire has resistance and will drop voltage over a distance.

Also match the wire and breaker size to the expected load. I did the rooms upstairs with 14/2 but the garage with 12/2

[MUSTANG]

The Bigger the wire, the greater the amperage it can handle. A 12 Gauge wire of 250 Foot would be the smallest size wire to use for a 20 Amp Service. (Just like a shotgun; The smaller the number the larger the wire. ie. 12 gauge is thicker than 14 Gauge, and 10 Gauge is larger than 12 Gauge.)

[375RUGER]

Use the Romex. I'd go with 10 or 8 AWG. With 10 AWG you will drop 8 volts in a run of 250 feet. With 8 AWG you will drop 5 volts. Assuming that you start with a nominal 120 volts this will keep you within the tolerance of most power equipment. So check the name plate voltage and you can operate the tools 90%- 110% or that.
If your starting voltage is only 115 and you drop 8 volts it puts you just outside tolerance for a 120V rated tool.

[djryan13]

I asked my electrician if he could run power to workshop. He recommended running temporary power using SOOW cord to a sub panel on shop. 250’ is a good distance to run Romex. There will be some voltage drop.

[Huskerguy]

I am not an electrician. So there is that. But there are charts readily available on this. I assume there eventually will be electricity in the building. Or if you are rural, won't they put a pole by your building? If you are eventually going to have power to the building, run it underground and it appears you need 4 gauge wire. Again, I am not an electrician, just doing some reading on this.

[Ickisrulz]

Are you considering running 250 feet of Romex across your lawn? Are you going to roll it up every time you are done with it (it's not made for that)? I have used 150 feet of 12 gauge extension cord temporarily (everyday over a year or so) and can tell you it is a pain to run out and then roll up each time.

I would (and have) run a sub-panel off of an appropriately sized breaker in your house to your outbuilding. The proper size wire can be selected from various sources online depending on how many amps you want. The cable is then buried directly or in a conduit. While you're at it, put some PEX in the trench and you'll have water out there too.

[Hossfly]

I would do what Ickisrulz suggest. Did that for all my out buildings. Barn,2 greenhouses. Direct bury wire 12’’ deep or deeper if in colder climate with water. Been buried 20+ years and no problem. Plenty power for future upgrades. I put 60 amp breaker and wire to barn 4 fans lee pot and lights and ptac a/c unit. Green House 40 amp for fans and pump.

[NyFirefighter357]

8/2 UF-B Wire w/ Ground 250ft

[Bazoo]

I don't have an exact plan. I was thinking underground Romex but on top of the lawn for the time being.

Money is tight, so I can't put a service in. I can't buy the wire right now either but I could come a lot closer to the wire. Using this building to make furniture to sell to a guy in town is my income. With the wife being sickly and having a baby, it's best if I can continue to work here instead of getting a job in town. Then of course I don't feel like working unless I can rest as much as needed. Anyways went on a tangent.

I've been using a generator for power at this building. My gen ain't delivering enough to run my tools anymore. They start only with help and bog down easy. Can't run the lights and a tool so I've been using flashlights whenever I have to saw or use the big sander at night.

Thanks for the advice.

[Misery-Whip]

6/3 UF aluminum is direct burial, I put it in conduit anyway. Went 65' and its good for 60 amps. Conduit, wire sub panel set me back $250. And a 24 pack of budweiser and 5gal of diesel for the neighbor to dig the trench, and cover it up.

Try buying the extension cord for that. I would get a 10 guage cord, but price the rental of a ditch witch, and the direct burial wire.

[Ickisrulz]

I don't have an exact plan. I was thinking underground Romex but on top of the lawn for the time being.

Money is tight, so I can't put a service in. I can't buy the wire right now either but I could come a lot closer to the wire. Using this building to make furniture to sell to a guy in town is my income. With the wife being sickly and having a baby, it's best if I can continue to work here instead of getting a job in town. Then of course I don't feel like working unless I can rest as much as needed. Anyways went on a tangent.

I've been using a generator for power at this building. My gen ain't delivering enough to run my tools anymore. They start only with help and bog down easy. Can't run the lights and a tool so I've been using flashlights whenever I have to saw or use the big sander at night.

Thanks for the advice.

I would suggest really thinking about what you want/need. You don't want to find out you need more power and have to upgrade your cables (or dig up your yard again). 20 amps isn't much power if you are running larger tools, lights, air compressor, etc. Are you going to heat/cool your building? That might require even more electrical power. I have a little workshop that is 15x16 where I do all my woodworking. I ran 100 amps into it. I never run out of power.

Yes, feeder cable can get expensive on the long runs.

Working with a flashlight while using power tools sounds dangerous!

[Plate plinker]

Not sure about your budget, but I would buy the appropriate size wire to keep working and then buy the conduit as money is available and bury it. A hot and a neutral of equal size and I believe you can use a smaller ground wire. My last cable purchase was from Wire and Cable your way.

[Mal Paso]

My iPhone app says 20 amps, 250 feet 8ga copper is a 5.75% voltage drop or 6.9 volts. 6ga copper is 3.68%. voltage drop or 4.4 volts if you are starting with 120 volts.

[wv109323]

My thoughts are a bigger generator to run your tools. Also I would use a car battery and battery charger to run led 12v lighting. I would compare cost of gen. To wire.

[Lloyd Smale]

i would go with 8 copper or 6 aluminum for a run that long and make sure you buy direct burial even if your going to run it over the ground. Underground wire is going to hold up not only to direct burial but will hold up to UV from the sun or getting nicked if you don't burry it which would be about insane. I would even check on your local codes. That said throw that advice in the garbage can. My guess a run that long is going to be a violation without a separate feeder panel and up here anyway a 100 amp service and fuse panel to come into. Get you advice from your local electrical inspector not some bullet casters. If someone gets hurt and it isn't up to code you are in for a world of you know what. Electrical codes are there for a reason. The reason is to protect PEOPLE

[Lloyd Smale]

i would go with 8 copper or 6 aluminum for a run that long and make sure you buy direct burial even if your going to run it over the ground. Underground wire is going to hold up not only to direct burial but will hold up to UV from the sun or getting nicked if you don't burry it which would be about insane. I would even check on your local codes. My guess a run that long is going to be a violation without a separate feeder panel and up here anyway a 100 amp service, 100 amp rated wire for that distance and fuse panel to come into. Get you advice from your local electrical inspector not some bullet casters. If someone gets hurt and it isn't up to code you are in for a world of you know what. Electrical codes are there for a reason. The reason is to protect PEOPLE

[DocSavage]

I'm not an electrician so when the OP says an extension cord I think something premade with plugs on both ends. 250' of that doesn't sound like a good idea,that said a generator for tools,12 volt light system from a deep cycle battery and a solar panel to keep the battery charged seems to be the way to go and depending on where he lives the genie could pull double duty for temp power for the house if weather causes power outage.

[Rich/WIS]

Would there be problem running 12-3 wg. That would allow two 20 amp circuits, but not sure if using the same neutral and ground is okay or not, hopefully a real electrician will chime in on that.

[georgerkahn]

Would there be problem running 12-3 wg. That would allow two 20 amp circuits, but not sure if using the same neutral and ground is okay or not, hopefully a real electrician will chime in on that.

Running 12-3 wg is what I ran to my shed, albeit I'm only about 120 feet. I modified a 30amp water-heater disconnect box by replacing its 30A 2-pole circuit breaker with two 15amp breakers. My thought (which has proven to be a good one ) is to use one leg exclusively for lighting -- I have four 40-watt twin florescent fixtures complemented with incandescent sockets each housing a 150watt light bulb. The 2nd breaker is a GFCI one -- deemed smart to have in an open shed -- and that feeds several female duplex receptacles (aka, "outlets") . Although I have never needed it -- nor believe I will in near future -- a "plus" I had in mind is that, with each leg on the other side of neutral, there is 220V from one to the other -- so, in a short-term situation, and just a wee bit of jerry-rigging, I can provide power to something requiring 220VAC.
My thoughts on your challenge include the fact that air conditioners, dehumidifiers, freezers, and fridges do NOT do well on sub-level "low" or challenged power. Even with today's modern technology, the starting amperage on these is quite high! However, for most motors, lights, casting furnaces, and the like -- I'd suggest you be OK, and 12-3 wg copper will suffice.
BEST!
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