Question for electrical gurus

[Ultradog MN]

I want to run an underground feeder about 220 feet.
Would like it to be capable of handling 20 amps.
I was thinking of running a 110 30 amp breaker and 10-2 underground romex.
Is my wire heavy enough?
Could I get by with 10-2?
Thanks

 

[Chris(WA)]

You should be up to at least a #6 wire for a run that long to carry that much amperage.

 

[Hogleg]

I ran 400 ft of stranded copper #10 to my barn in plastic conduit and put a 20 A breaker on it. Used a small 2 breaker panel in the barn to distribute it. Works ok. Sometimes dims the lights when I start a large fan. I normally run lights and horse fans in the summer and tank heaters in the winter. Was able to run a small compressor just fine. If I were to do it again, I would run #8 or possibly #6.

I am sure I will get yelled at for sharing this with you.

An electrical guy will chime in in a while I am sure to tell you what code is.

My main reason for reply is you should really run 3 wires plus ground. For not much more, you get 2 legs of power instead of one. You then used a ganged breaker to feed it.

John

 

[Dusty MI]

Google voltage drop, just put in what you want and it will tell what size wire. I wouldn't use more than 2%.

Dusty

 

[John T]

Lets take your post one at a time:

QUESTION Is my wire heavy enough?

NOOOOOOOOOOOO

If my sources are correct, NO WARRANTY, did this in a hurry, 10 AWG wire,,,,,,220 Feet,,,,,,,,,,,20 amps,,,,,,WOULD DROP 9.04 Volts

QUESTION Could I get by with 10-2?

NOOOOOOOOOOOOOO

But if you used 6 gauge wire the Voltage drop would only be 3.58 volts

NOTE If you want to run 120/240 volt Single Phase Three Wire service to a remote outbuilding, you need FOUR WIRES (per latest NEC)

Two Hot UnGrounDED Conductors, L1 & L2
One Neutral GrounDED Conductor
One Equipment GrouindING Conductor

DO NOT bond Neutral and Ground at the remote sub panel, they are to remain seperate and isolated unlike at the main panel. A GroundING Electrode is required at the outbuilding.

If you only want 120 volt single phase, you only need THREE WIRES

One Hot UnGrounDED Conductor
One Neutral GrounDED Conductor
One Equipment GroundING Conductor

NOTE The switching equipment and overload protection used at the remote outbuilding depends on the load and how many circuits and purpose etc.

NOTE Every buildings electrical service requires Grounding

I'm sure I missed a few things (Too long retired as an EE and rusty on latest codes) so hopefully the other professional electricians and engineers can add more to this SO NO WARRANTY. Consult local trained professional utility providers and electricians and inspection authority NOT ANY OF US HERE including yours truly, as they, none of us, are what matters most. BEWARE of untrained non professional Billy Bobs (wired thier own home over a case of beer) lay opinions that could cause a fire or get you killed

Best wishes, keep safe and Happy Fathers Day

John T Too long retired EE

 

[Ultradog MN]

I'll elaborate a little.
This is for a deer stand I'm building. It's about 200' from one of my rental houses. I'd like to plug in a 110v 1500W milkhouse heater.
Unplug that to run an electric coffee pot. Maybe a radio. One 60W overhead light which wouldn't get used much.
8'X7' building is insulated to R13 or better.
Do I still need bigger than 10 ga?

 

[John T]

Based on your updated info: A 120 volt 1500 watt heater will draw 12.5 amps, so if you use 10 gauge copper wire for a 220 foot run you would drop 5.65 volts AND SURE (Billy Bobs) THE HEATER WILL STILL WORK if thats what you want to hear (still excess voltage drop if that matters). As I posted earlier, for 120 volt only all you need is three wires, Hot UnGrounDED Conductor, Neutral GrounDED Conductor, Equipment Ground.

I would definitely recommend you feed that circuit with GFCI protection.

So "we report now you decide" your money your choice, yes the heater and light will work. Heck it will "work" if you used 12 gauge. If it has a fan it could draw excess current and run a bit on the warm side, no way to tell exactly absent all the design specs. If youre using a heater at way less then the required voltage, Id use one that didnt have a fan. The heater may have specs like 110 to 125 etc. OF COURSE, the more voltage you start with at your panel, the more thats available out on the end of the loaded circuit. If you started with say 120 and dropped 6 you still have 114 at the load AND THATS NOT ALL THAT BAD to operate a 120 volt nominal resistance heater!!!!!!!!!!!

John T

 

[greygoat]

Hope the smell of that fresh brewed coffee wakes
the deer up!

 

[Ultradog MN]

Thank you John.
I do understand about the hot, netutral and ground. As I understand it the voltage isn't as critical on a heater as it would be on say, a motor.
Yeah I agree it's Billy Bob electrical but was trying to get by on the cheap. Even 10 ga UF wire is going to cost me more than the whole rest of the building will. Good idea on the GFI. I'll put one in the circuit as it leaves the house.
There's really not much chance of it getting used for anything else as the stand is pretty remote relative to any other buildings, etc.

 

[John T]

If all I was running was a 120 volt resistance heater and maybe a light bulb, heck Id likey run a 10/3 cord, its just as a safety minded engineer and attorney I hate to give bad or knowingly wrong advice....

Nuff said

John T

 

[Ultradog MN]

[i:654c4848f0]"its just as a safety minded engineer and attorney I hate to give bad or knowingly wrong advice...."[/i:654c4848f0]

Ah yes,
The burden of a legal education. wink

 

[John T]

When we entered Law School the instructors warned us it would be a curse the rest of our lives, always weighing both sides and considering the consequences and over analyzing every little detail i.e. thinking like a lawyer grrrrrrrr and its even worse having first been an engineer lol

John T

 

[Ultradog MN]

A few years ago I did a bunch of remodeling for a patent attorney here in the Twin Cities.
He started out in life going to 2 years of vo tech to be a heavy diesel mechanic. Got a job doing that and realized he really didn't like it.
Went back to school and got an EE degree. Lot of turnover in that industry which is not conducive to raising a family so he went to law school.
It was him who told me about it sometimes being a burden - especially when he had to pay big bucks for a real estate attorney to have peace of mind when he bought a cabin.
BTW, he works from home. In his office the only sheepskin he has on display is the one from diesel school.

 

[john in la]

Google wire size calculator and you will get several hits so you can figure wire size.

You said a 1500w heater and maybe a light bulb. Lets call it 1600w.
1600w/120v = 13.3 amps
Since you can get a 15 amp breaker lets go with that because those 2 amps is not going to change the wire size.

That means you need 6ga wire for that run if you use copper. A 15 amp breaker with a 6ga wire
will give you 1800w to use at one time.

May not be what you wanted to hear.

Wire Size Calculator

 

[john in la]

PS.................

If you could get a 220v heater; a 220v light bulb and do without the coffee then we could talk wire in the 10ga size on 15amps.

 

[Geo-TH,In]

I would run 220v, 30 amp breakers, 10-3 with ground. Wire up a 6 ft, 1500w, 220v baseboard heater, which you will never have to worry about in your life time and have room to add more things if needed. Don't think the extra wire would make you go broke. Going have to buy 250 ft roll, unless you find some place that sells it by the foot.

 

[John T]

While its been years since I retired as an Electrical AC Power Distribution Design Engineer, we were required (in my day at least) to use the 80% rule, which meant if the breaker was a 15 amp, the branch circuits max "continuous" load should not be greater then 12 amps (80% 0f 15). Therefore, if the max "continuous" load turned out to be 13+ amps, we were required to utilize a 20 amp breaker and appropriate wire size. I'm guessing his breakers are "Thermal Magnetic" and a constant 13.3 amp draw is going to cause the thermal portion of the breaker to get "nervous" I will call it lol

I also computed the voltage drop and agree 6 gauge will work (to comply with strict code) but for what he's planning I think hes going to use 10 ????? His choice, we report, he decides!!

Fun sparky chattin with you

Ol John T in Indiana

 

[JMOR]

Everything does not have to be to NEC book. The safety of life & property stuff, I''ll work, but 3% voltage drop, I treat as "nice to have", especially outdoors. For over 15 years, I ran a 1/2 hp compressor 290 feet from the house over 12GA wire. House was at 125v & even at 15A, still had 110v at shed. Worked for me. Do what you need.

 

[36 Coupe]

Spend more money and use # 6 then you can run a welder.Being cheap dosent pay,You should know that.

 

[JMOR]

(quoted from post at 16:04:12 06/16/13) Spend more money and use # 6 then you can run a welder.Being cheap dosent pay,You should know that.

Yeah, who knows when he may need a welder in his deer stand! :twisted:

 

[Bill in IN]

Not sure I would be too concerned about 5% drop on a heater or a incandescent lamp though.....

 

[dr sportster]

Heck, you could get by with better thermal underware and a thermos. We are talking about a tree stand !

 

[Stan in Oly, WA]

How did your knee surgery go, Dave? Well, I hope.

Stan

 

[dr sportster]

Surgery went well. Strength needs alot of work. Thanks Stan

 

[36 Coupe]

Why not, any body who needs electricity in a deer stand aint wrapped too tight.Gotcha..

 

[36 Coupe]

A friend built a tree house many years ago.He wanted some heat so he bought a reeves dover sheet metal wood stove.Cost 5 bucks back then.He got it fired up and burnt the tree and house up.Calvin Rutstrum put a propane heater in his out house that he could switch on from the cabin.A friend was drinking a few beers and emptied his pipe down the hole.Out house caught fire.Vol. F D showed up and was laughing so hard they decided to let it burn.Willie said they brought some lumber and helped him build a new out house next day.Coffee up in a tree aint a good idea.If you pee close to the tree it will spook the deer so you better have a gallon jug handy or 2 if you drink much coffee.

 

[Ozlander]

(quoted from post at 13:11:00 06/16/13)

(quoted from post at 16:04:12 06/16/13) Spend more money and use # 6 then you can run a welder.Being cheap dosent pay,You should know that.

Yeah, who knows when he may need a welder in his deer stand! :twisted:

And a TV.