Wire choice for 200' run to garage?

[Innovate1]

I have changed plans on location and have a 200' run to house panel. Had planned to run 90A but could go with less. Any good options for smaller aluminum wire for less current? 60A should be more than enough. Or should I go to copper? I need to check if I can use aluminum because some areas here it isn't allowed for any wiring (except poco).

 

[mike93lx]

What are your loads?

That would be an awful lot of work and money for a "should be enough".

Conduit or direct bury?

I would be amazed if you can't run AL.

 

[gmtech]

I had a 165' run to my new shop. I ran 2-2-2-4 mobile home feeder wire in 2" conduit. By my voltage drop calculations, I'm good for 70 amps. 70 amp breakers are expensive and harder to find so I breakered at 60. I have a 2 post lift, air compressor etc with no issues.

Sent from my SM-G973U using Tapatalk

 

[Innovate1]

I looked again at the rules for the location I was thinking of. It states no aluminum for run from weatherhead into panel box. Not sure if it has changed over the years. AL is not currently noted as not allowed otherwise.

For loads that is a hard one as I don't know exactly what I will be doing. Probably a modest compressor, 2 ton AC, gas furnace, maybe a small welder, some wood working equipment, perhaps a connection for an RV. It's a one man hobby shop. Hard to imagine I would need over 60A but was going to go for 90A since the wire and such isn't much more. Wire run is about twice what I had figured for another location and getting a large conduit continuous to the house panel (inside the house) is a little harder so am rethinking the electric.

 

[dcg9381]

So you're OK with AL wire, right? Your exclusion seems to be for overhead power. Please confirm.

I think you're (ballpark) on that 60-90A will work. You're in Missouri - so it's not like you'll be hammered by 2 x RV HVAC units all summer. A 50A RV connection can typically supply 4 AC systems running.

200' is a decent length run.

It looks like you can get away with 3GA copper or 1GA AL at 80A per this calculator.


Nearest options I see:
2/0-2/0-1-4 MHF 1.92/ft (do calculation, but this will do over 100A)
2GA copper x 3 + appropriate ground - about 4.25/ft (80A)
1/0AWG aluminum + appropriate ground $2.00/sqft (80A)

 

[jeepxj]

for 200 bucks i'd sink some 2" conduit in and then never worry about it again. pull in more if you want more in the future. don't forget a run of 3/4" for data too.

 

[Innovate1]

for 200 bucks i'd sink some 2" conduit in and then never worry about it again. pull in more if you want more in the future. don't forget a run of 3/4" for data too.

Great advice! Although I could go to 1" for data for only $25 more. And 2" is only about $25 more than 1-1/2 so worth it although with the bends and end fittings its a bit more difference.

I am a little confused by the size of the power conductors though. The code table states #2 AL is good for 90A but the calculators seem to assume 60C numbers or something that makes it at least 1/0. And 1/0 easily meets 3% voltage drop and I can't enter smaller to see the drop.

http://www.paigewire.com/pumpWireCalc.aspx?AspxAutoDetectCookieSupport=1

Southwire has one that looks a bit more flexible:
https://www.southwire.com/calculator-vdrop

For 240V and 200 ft and 90A it shows 2/0 and 2.44% voltage drop.

If I switch to circuit distance instead of conductor size and enter #2 AL it complains that it might not be good at that current but shows 136 ft max for 3% drop and 227 ft for 5% drop.

#1 increases length to 165 for 3% and 220 ft for 4% which I am thinking would be fine since I seriously doubt I would ever get to 90A. I suppose I could put a slightly smaller breaker on it.

How do I size the neutral and ground? I have seen a few places that the neutral is not to be reduced but not sure that is required or applies. Some of the loads are 230V - notably the AC but that's not a big load.

For the ground conductor if I assume #2 for 90A as the starting point and use 250.122B for the increase to #1 then I need to increase the EGC from panel to panel from #6 AL to #5 AL. Since 5 is not a standard size go to #4.

So I end up with 1/1/1/4. Does that look right?

I did notice on wiresandcablesyourway.com that #4 is available only in black while larger sizes are available in black and green. Is it acceptable to mark the black as green for the EGC?

And for the wire from the subpanel to the ground rods #8 Cu.

 

[Norcal]

If a conductor is #4 and larger, then it may be marked with another color.

 

[Innovate1]

I see wiresandcablesyourway has 2/0-2/0-1-4 MHF for $1.92/ft. Only slightly more than 1-1-1-4 strands of XHHW ($1.82). But it has a small neutral. What's the story on that? And with the larger conductors it would require a larger ground conductor too unless I am missing something. It would be slightly harder to pull but with 2" conduit and 2 large radius 90s it shouldn't be too bad. Are standard LBs big enough for it?

 

[ard]

for 200 bucks i'd sink some 2" conduit in and then never worry about it again. pull in more if you want more in the future. don't forget a run of 3/4" for data too.

I did that 20 years ago. 300 ft

Now I cannot pull pre-terminated Fiber. Should have just tossed in 1.5inch

MHF is a no brainer IMO

 

[dcg9381]

Data can easily be done in 3/4 or even 1/2 conduit, just get shielded copper (if doing copper). Fiber would be better if you can deal with it. Radio for line of site works too (ubiquiti).

A member pointed out to me that Paige wire calculator assumes 53º C - that's why it will differ from others.


Here are the tables to decide how much wire fits in PVC conduit. I've read two things:
* Oversizing the conduit allows wire to twist and that makes things harder. Can't confirm.
* Electrician here that I talked to said that many areas now require that all "mains" are 3" conduit. You're obviously not doing a main, but it's kinda future proof. The reduce to 2.5" at the panel.

If conduit size is tight for the wire, pulling 2 x 90s might be a challenge.

Confirm that your panels and breaker are rated for the size of the wire you choose. May will have a temp rating also.

 

[Innovate1]

No way I would put in 1/2". I will have more than one cable - security + network and maybe phone and TV. But even if I only had one I would do at least 3/4. Not much cost difference.

I think what you are referring to about harder pulls if the wire twists is "jam ratio". There are formulas to determine if it will be an issue. Here's an old article about it - had to use the wayback machine to get the figures. It's for much bigger wire but the basics are the same. There are numerous sites with info on this.

https://web.archive.org/web/20121108074838/https://www.ecmweb.com/content/simple-calculations-cable-pulling

 

[Bretny]

Google wite size calculator.

 

[jeepxj]

I did that 20 years ago. 300 ft

Now I cannot pull pre-terminated Fiber. Should have just tossed in 1.5inch

MHF is a no brainer IMO

aight land 2 runs of 2" and 3 runs 5" to be really sure you got enough in the future.

 

[Innovate1]

I see wiresandcablesyourway has 2/0-2/0-1-4 MHF for $1.92/ft. Only slightly more than 1-1-1-4 strands of XHHW ($1.82). But it has a small neutral. What's the story on that? And with the larger conductors it would require a larger ground conductor too unless I am missing something. It would be slightly harder to pull but with 2" conduit and 2 large radius 90s it shouldn't be too bad. Are standard LBs big enough for it?

Can anyone answer my questions about size of neutral and ground conductors?

 

[ard]

aight land 2 runs of 2" and 3 runs 5" to be really sure you got enough in the future.

lol

Run some 30" and I can just crawl through myself!

 

[jeepxj]

lol

Run some 30" and I can just crawl through myself!

then before ya know it you got a buncha vaults all to draw 11amps of 120

 

[theoldwizard1]

Too much info flying by ! Double check my data (not a sparky).

XHHW is not rated for underground, either direct bury or in conduit. USE/USE-2 is, but I believe it requires a conduit. MHF can be direct buried, but requires a conduit inside of building (you could switch to SE/SER inside).

If you are tapping off of your main box with a breaker, there are restrictions on the maximum breaker (90A?).

For 60A at 200', 2AWG Al would have less than a 3% VD. For 90A at 200', 1/0 Al would have less than a 3% vd.

Neutrals are allowed to be smaller size because the assumption is the loads will include some 240V devices. I have no idea how this is calculated.

A ground conductor is always required although it is sized differently.

 

[mike93lx]

Too much info flying by ! Double check my data (not a sparky).

XHHW is not rated for underground, either direct bury or in conduit. USE/USE-2 is, but I believe it requires a conduit. MHF can be direct buried, but requires a conduit inside of building (you could switch to SE/SER inside).

If you are tapping off of your main box with a breaker, there are restrictions on the maximum breaker (90A?).

For 60A at 200', 2AWG Al would have less than a 3% VD. For 90A at 200', 1/0 Al would have less than a 3% vd.

Neutrals are allowed to be smaller size because the assumption is the loads will include some 240V devices. I have no idea how this is calculated.

A ground conductor is always required although it is sized differently.

Not sure why you think xhhw can't be used underground. As far as I know and can find online, it is fine.

Source?

 

[OccupantRJ]

I looked again at the rules for the location I was thinking of. It states no aluminum for run from weatherhead into panel box. Not sure if it has changed over the years. AL is not currently noted as not allowed otherwise.

For loads that is a hard one as I don't know exactly what I will be doing. Probably a modest compressor, 2 ton AC, gas furnace, maybe a small welder, some wood working equipment, perhaps a connection for an RV. It's a one man hobby shop. Hard to imagine I would need over 60A but was going to go for 90A since the wire and such isn't much more. Wire run is about twice what I had figured for another location and getting a large conduit continuous to the house panel (inside the house) is a little harder so am rethinking the electric.

Go for 90 amps. I cut 5,000 watts from the original 10,000 of the electric strip of my heat pump because of pushing it when the strips kicked in. I have 60 amps and run mills, lathe, compressors, big bandsaws, etc. I have the conduit run for a future 90 amps, as mine is direct burial now.

 

[Sokoloff]

XHHW is not rated for underground, either direct bury or in conduit.

XHHW is rated for underground usage in conduit. You might be thinking about THHN, which can’t be used underground or in other wet locations (if it’s only marked as THHN; if it’s also marked THWN, you can.)

 

[wyliesdiesels]

Too much info flying by ! Double check my data (not a sparky).

XHHW is not rated for underground, either direct bury or in conduit. USE/USE-2 is, but I believe it requires a conduit. MHF can be direct buried, but requires a conduit inside of building (you could switch to SE/SER inside).

If you are tapping off of your main box with a breaker, there are restrictions on the maximum breaker (90A?).

For 60A at 200', 2AWG Al would have less than a 3% VD. For 90A at 200', 1/0 Al would have less than a 3% vd.

Neutrals are allowed to be smaller size because the assumption is the loads will include some 240V devices. I have no idea how this is calculated.

A ground conductor is always required although it is sized differently.

XHHW is most definitely rated for underground use....

 

[theoldwizard1]

Not sure why you think xhhw can't be used underground. As far as I know and can find online, it is fine.

XHHW is rated for underground usage in conduit.

XHHW is most definitely rated for underground use....

SCREWED UP AGAIN ! Can XHHW be direct buried ?

 

[mike93lx]

SCREWED UP AGAIN ! Can XHHW be direct buried ?

No. It requires conduit

 

[alfredeneuman]

SCREWED UP AGAIN ! Can XHHW be direct buried ?

No it can't.
The hint to it's wet location rating is the "W".
As an example THHN isn't rated wet, while THWN is

 

[Bert_]

Can anyone answer my questions about size of neutral and ground conductors?

I almost always reduce the neutral. Reducing by two sizes is usually accepted without any calculation. More than that an you need to do the calculation. I often run a neutral that is 1/2 size or even less on sites with mostly line to line loads.

Even without 240v loads the 120v stuff will balance out because it is split between the two line wire. The neutral only carries the imbalance.

 

[Innovate1]

2-2-2-4 MHF can support 60A at that distance although I can get 2-2-4-4 as single strands of XHHW for only about $10 more. Seems like the easier pull would be worth it.

 

[mike93lx]

2-2-2-4 MHF can support 60A at that distance although I can get 2-2-4-4 as single strands of XHHW for only about $10 more. Seems like the easier pull would be worth it.

If in conduit the whole way, xhhw is the way to go.

 

[themiller]

How old are you and are you (or family you actually care about having visit) ever going to get an electric car?

Don't actually have to answer, just something to think about...

 

[dcg9381]

I use a 50A RV connection in my garages for "future EV" - 50A seems to be the standard.
Two things really tend to drive up the requirements for inbound power:
1) Instant on electric hot water
2) EVs

 

[jeepxj]

50a is plenty for EV's in a daily driver situation. rough math is 3 miles per KWH at current efficiency levels. so at 10kw charging rate you're getting 30mph range added.
The tesla units are nice in the fact they can be on the same circuit and talk to each other to manage power demand between up to 4 chargers.

I would rather boil water on a campfire and hand pump my shower than use an electric on demand water heater.

 

[Norcal]

50a is plenty for EV's in a daily driver situation. rough math is 3 miles per KWH at current efficiency levels. so at 10kw charging rate you're getting 30mph range added.
The tesla units are nice in the fact they can be on the same circuit and talk to each other to manage power demand between up to 4 chargers.

I would rather boil water on a campfire and hand pump my shower than use an electric on demand water heater.

As much as I hate propane, that is the best choice for a tankless if natural gas is not available, rather then go electric just because of the large power demand of electric models.

 

[jeepxj]

As much as I hate propane, that is the best choice for a tankless if natural gas is not available, rather then go electric just because of the large power demand of electric models.

I'd consider a heat pump water heater: