What wire gauge for 30A 120’ away?

[jeremyclarkson]

Hi,

I want to run both 110v and 240v to my backyard shed that’s 120’ from the house panel.

I plan to bury the wire myself and let the electrician to do the final hook up.

lm looking to use teck cable that approved for bury at 20” depth

few questions:
1. What gauge should I use for 30A at 120’? 3AWG aluminum?
2. How many cores should I run if I want both 110v and 240v?
3. How does the power transmission work? Does power get delivered using 240v from my main panel to subpanel then split into 110v?

 

[MoonRise]

4 AWG aluminum.

Voltage Drop Calculator | Southwire

www.southwire.com

You will have ~7 volts of voltage drop at 30 amps over that length of 4 AWG aluminum.

You have 120 ft out to the shed, and 120 ft back, so you have a total of 240 ft of wire that the current has to travel.

You have to run 4 wires out to the shed, hot-hot-neutral-ground.

You will have a double-pole 240V breaker in your main panel, that will be running to the wire out to the shed. In the shed the incoming wires (4 wires, remember) will go into a subpanel. That subpanel will then distribute the power to the circuits in the shed. Both 240V circuits and separate 120V circuits.

 

[kinglake]

4 AWG aluminum.

Voltage Drop Calculator | Southwire

www.southwire.com

You will have ~7 volts of voltage drop at 30 amps over that length of 4 AWG aluminum.

You have 120 ft out to the shed, and 120 ft back, so you have a total of 240 ft of wire that the current has to travel.

You have to run 4 wires out to the shed, hot-hot-neutral-ground.

You will have a double-pole 240V breaker in your main panel, that will be running to the wire out to the shed. In the shed the incoming wires (4 wires, remember) will go into a subpanel. That subpanel will then distribute the power to the circuits in the shed. Both 240V circuits and separate 120V circuits.

You sure about your 7v? I get 3.3.

 

[mike93lx]

Location is very important. Mentioning teck makes me assume Canada

If I was trenching that far, I'd likely run 2-2-2-4 MHF (if direct bury) or the same sizes in Xhhw. The wire is not a huge cost and it would give you an easy 60a. All the other stuff is basidally the same as 30a (breaker box, ground rods, breaker for the main panel). But I have no idea what wire is available in the great white north.

 

[alfredeneuman]

According to this calculator #6 Al wire in PVC conduit will do it
Voltage drop: 5.15
Voltage drop percentage: 2.15%
Voltage at the end: 234.85


https://www.calculator.net/voltage-drop-calculator.html

 

[alfredeneuman]

You have 120 ft out to the shed, and 120 ft back, so you have a total of 240 ft of wire that the current has to travel.

Most, if not all, VD calculators use the one way distance.

 

[Terry D]

4 AWG aluminum.

Voltage Drop Calculator | Southwire

www.southwire.com

You will have ~7 volts of voltage drop at 30 amps over that length of 4 AWG aluminum.

You have 120 ft out to the shed, and 120 ft back, so you have a total of 240 ft of wire that the current has to travel.

You have to run 4 wires out to the shed, hot-hot-neutral-ground.

You will have a double-pole 240V breaker in your main panel, that will be running to the wire out to the shed. In the shed the incoming wires (4 wires, remember) will go into a subpanel. That subpanel will then distribute the power to the circuits in the shed. Both 240V circuits and separate 120V circuits.

You only figure the one way distance. That is why your voltage drop is double than what it should be. Even the standard formula uses one way distance

VD = 2k x L x I /Cm

 

[Terry D]

Double post

 

[MoonRise]

my bad, I was used to whatever online voltage drop calculator that I used to use, where you had to enter the total distance (there AND back) for some reason.

120 ft distance and 30 amps thus calls for a minimum of 6 AWG aluminum.

4 AWG aluminum gives you a little extra head room (amperage room? ) though.

3 AWG gives even more amperage room. And then you could run a 60 amp subpanel. ~5 V voltage drop at 60 amps, 2.25% voltage drop.

Some 2-2-2-4 gives you even more amperage-room.

 

[alfredeneuman]

You have to run 4 wires out to the shed, hot-hot-neutral-ground.

You will have a double-pole 240V breaker in your main panel, that will be running to the wire out to the shed. In the shed the incoming wires (4 wires, remember) will go into a subpanel. That subpanel will then distribute the power to the circuits in the shed. Both 240V circuits and separate 120V circuits.

Not necessarily. If your area's adopted code is the 2020 NEC the rules have changed. You can run them separately. NEC did away with the "1 feed to an outbulding" rule.

 

[Innovate1]

Not necessarily. If your area's adopted code is the 2020 NEC the rules have changed. You can run them separately. NEC did away with the "1 feed to an outbulding" rule.

That may be true but practically running separately would require even more wires, at least 3 for each which is 6. Doesn't make any sense to do that except maybe to add a run to an existing installation or maybe if you wanted to control a load from the other building.

 

[wyliesdiesels]

Not necessarily. If your area's adopted code is the 2020 NEC the rules have changed. You can run them separately. NEC did away with the "1 feed to an outbulding" rule.

and the OP is most likely in canada, so NEC code doesnt matter here

 

[jeremyclarkson]

Thanks all.

I'm located in Canada.

So I assume minimum #6. for 30A at 120'.

Few questions:
1. Any disadvantage of running #2 except the obvious material cost? Will electrician charge me more for hooking up #2 since it is bigger and harder to work with than #6?
2. I want to make the run simpler so instead of running conduit, I want to use Teck90 type of direct burial armoured cable.

Would this one work:

2/3C ACWU90 Aluminum Cable

www.gescan.com

3 condutors (do I assume it comes with a ground also?), #2, rated for direct burial.

3. Is it a good idea to bury the electrical line in the same trench as water/sewage line? I plan to dig 4' for water, backfill 1', then put in electrical at 3'. Does this make it harder to repair the sewage line later since I can't machine dig the trench?

 

[MoonRise]

Oooh, Canada.

Let's see if I can speak (type? ) Canadian.

Contact Hydro or the ESA and find out what their current (no pun intended ) requirements are, eh.

Or just ask your Canadian electrician.

And also find out (Hydro, ESA, or your electrician ) what the permit requirements are.

 

[mike93lx]

We don't use that teck stuff in the US and I don't think we have any Canadian sparkies here.

We would need a 4 conductor cable, but I think our grounding requirements are different.

I wouldnt expect a material, if any, difference in cost from an electrician to deal with #2 vs #6, but anything is possible

 

[Metal-Marc]

Ask your electrician to supply the cable. This way you're sure to get the correct cable, and have a happy electrician.

 

[wyliesdiesels]

We don't use that teck stuff in the US and I don't think we have any Canadian sparkies here.

We would need a 4 conductor cable, but I think our grounding requirements are different.

I wouldnt expect a material, if any, difference in cost from an electrician to deal with #2 vs #6, but anything is possible

theres actually a few in the group

 

[mike93lx]

theres actually a few in the group

If We say their names three times, do they show up?

Canadian sparkies... Canadian sparkies... Canadian sparkies!

 

[walrus]

Who says no one uses teck cable in US, I've used it several times and see it once and awhile. Not common but it gets used here

 

[Innovate1]

#2 will cost more for materials. Probably only a bit more for labor. How big is this "shed"? What's the chance that you will want more than 30A in the future? With #2 AL you can probably go with 60A (didn't do the voltage drop but it's oversized for 60a). That's a nice size for a shop building and will allow you to do many things there. Put in a subpanel that is big enough to add circuits later - a bigger panel isn't much more than a small one. You can use a bigger main breaker in the subpanel as the overcurrent protection is the breaker in the main panel feeding it. A lot of small panels have 100A mains which is fine.

 

[alfredeneuman]

theres actually a few in the group

If members would fill out their profile completely, including location, we wouldn't have this problem.

 

[Being]

Hi,

I want to run both 110v and 240v to my backyard shed that’s 120’ from the house panel.

I plan to bury the wire myself and let the electrician to do the final hook up.

lm looking to use teck cable that approved for bury at 20” depth

few questions:
1. What gauge should I use for 30A at 120’? 3AWG aluminum?
2. How many cores should I run if I want both 110v and 240v?
3. How does the power transmission work? Does power get delivered using 240v from my main panel to subpanel then split into 110v?

#8 alu x4, 2 hots, 1 neutral, 1 ground. Master Electrician from ND.

 

[alfredeneuman]

#8 alu x4, 2 hots, 1 neutral, 1 ground. Master Electrician from ND.

Voltage drop: 8.22
Voltage drop percentage: 3.42% (Above suggested maximum value of 3%)
Voltage at the end: 231.78

 

[75gmck25]

2-2-2-4 AL Mobile Home Feeder (MHF) is often used in the US because it easy to find and relatively cheap. It will handle up to 90 amps, but 60 amp breakers for the main panel are cheaper and easier to find. It can be direct buried, but I prefer to run it in 2" conduit to provide plenty of room to pull the wire. With all the changes due to supply shortages, I don't know current wire prices, but I assume MHF is still a good budget alternative.

 

[PoorUB]

Thanks all.

I'm located in Canada.

So I assume minimum #6. for 30A at 120'.

Few questions:
1. Any disadvantage of running #2 except the obvious material cost? Will electrician charge me more for hooking up #2 since it is bigger and harder to work with than #6?

Trying to hook up #2 wire on connections rated for 30 amps may be an issue. I don't know why you would ant to go larger unless you may want to upgrade the panel size later.

 

[alfredeneuman]

2-2-2-4 AL Mobile Home Feeder (MHF) is often used in the US because it easy to find and relatively cheap. It can be direct buried, but I prefer to run it in 2" conduit to provide plenty of room to pull the wire. With all the changes due to supply shortages, I don't know current wire prices

Currently Southwire lists their 2-2-2-4 for $5516 per thousand. It would cost ~$718 for 130'
#6 THHN/THWN aluminum is $820 per thousand and X 4 would cost ~$322 for the same run

 

[mike93lx]

Currently Southwire lists their 2-2-2-4 for $5516 per thousand. It would cost ~$718 for 130'
#6 THHN/THWN aluminum is $820 per thousand and X 4 would cost ~$322 for the same run

I don't know what shenanigans that is, but AL 2-2-2-4 MHF is under 2.50/ft at wireandcabelyourway.com

 

[sparky 1971]

Currently Southwire lists their 2-2-2-4 for $5516 per thousand. It would cost ~$718 for 130'
#6 THHN/THWN aluminum is $820 per thousand and X 4 would cost ~$322 for the same run

Holy ****. I just checked the supply house I use and 2-2-4-6 MHF is $1.93 per foot. The only place I know of around here to get 2-2-2-4 is Menards and it's $1.88/ft.

 

[theoldwizard1]

Currently Southwire lists their 2-2-2-4 for $5516 per thousand. It would cost ~$718 for 130'

Wire and Cable Your Way $2.43/ft plus shipping

 

[alfredeneuman]

I don't know what shenanigans that is

I got it straight from Southwire
https://www.southwire.com/pricing

 

[mike93lx]

I got it straight from Southwire
https://www.southwire.com/pricing

Who pays MSRP?

 

[alfredeneuman]

Who pays MSRP?

OK. Since you mentioned Wire Your Way… Wire prices from WYW and conduit (less fittings) from Lowes.
2-2-2-4 MHF - $2.43 per ft. 2” Conduit – $2.68
Total Cost = $664
2-2-2-4 w/ 1-1/2" = $570
Individual (same) XHHW wires w/ 1-1/2" = $514
Individual #6 w/ 1-1/4" conduit = $386
I can think of better things to do with $278

 

[mike93lx]

OK. Since you mentioned Wire Your Way… Wire prices from WYW and conduit (less fittings) from Lowes.
2-2-2-4 MHF - $2.43 per ft. 2” Conduit – $2.68
Total Cost = $664
2-2-2-4 w/ 1-1/2" = $570
Individual (same) XHHW wires w/ 1-1/2" = $514
Individual #6 w/ 1-1/4" conduit = $386
I can think of better things to do with $278

you said the wire is $5.56/ft and i provided a reference for half that cost. that's it.

regarding #2 vs #6, you may do something differently than me. I still feel that if i was going through the trouble to trench, and was already putting a panel in, I'd go for larger wire. 386 vs 514 is not a huge difference and it would be a pain to change later, plus far more costly.

 

[alfredeneuman]

I'd go for larger wire. 386 vs 514 is not a huge difference and it would be a pain to change later, plus far more costly.

That's for individual wires, not MHF like you suggested.

 

[PoorUB]

regarding #2 vs #6, you may do something differently than me. I still feel that if i was going through the trouble to trench, and was already putting a panel in, I'd go for larger wire. 386 vs 514 is not a huge difference and it would be a pain to change later, plus far more costly.

Depending on the situation I might agree, but if you are running wire out to a small shed and there is zero chance that you might put a larger building in the same spot for the lack of room, then why spend the extra money?

My buddy ran a 240 volt circuit 75 feet out to his dock to run a boat lift and irrigation pump. He seriously thought of running one 120 volt 20 circuit but talking to me he pretty much convinced himself to put a small panel out there with a 240 breaker for his irrigation pump and a couple 120 volt outlets. I forget but I think he ran #8 wire. Now in his situation it would be pretty hard to see the need for much more so why bother run heavier wire?

 

[tarmy]

Depending on the situation I might agree, but if you are running wire out to a small shed and there is zero chance that you might put a larger building in the same spot for the lack of room, then why spend the extra money?

My buddy ran a 240 volt circuit 75 feet out to his dock to run a boat lift and irrigation pump. He seriously thought of running one 120 volt 20 circuit but talking to me he pretty much convinced himself to put a small panel out there with a 240 breaker for his irrigation pump and a couple 120 volt outlets. I forget but I think he ran #8 wire. Now in his situation it would be pretty hard to see the need for much more so why bother run heavier wire?

I got two additional boats and two more winches…same situation…

If I am doing trench, I always put one or two extra 1” conduits in…some I have never used…most however have had something added later. We ended up with tree lights, a gazebo, more boats and new deck and fire pit by the lake…

For me, wire is cheap (well, it was) and I always either pull an extra set or two, or upsize to have it there for future. My place has several outbuilding and structures on an acre and a half….so I have a lot of trench down…

 

[PoorUB]

I got two additional boats and two more winches…same situation…

Sure, but how often do you run both winches at the same time? most people would run or the other, or a bit of discipline and you could easily run them off one 20 amp breaker.

 

[tarmy]

Sure, but how often do you run both winches at the same time? most people would run or the other, or a bit of discipline and you could easily run them off one 20 amp breaker.

Agreed. And I agree with your previous post As well. I am just one of those guys that likes to overdo stuff. i do operate two winches at a time sometimes as they run a set up for raising a lowering a 26’ gangplank at both ends as water levels change. Most folks are not using multiple power draws and your suggestion is sound advice For them.