Attached Garage Power - Long Run Stranded vs Solid

[krm2b2]

I am adding additional power to my attached garage in order to run my wood working equipment. The original plan was to run 6AWG to a 60amp sub panel, but after some investigating I realized this was going to get quite expensive. I have room in the 200 amp service panel in the basement so my next thought was to run three branches to the garage (1 -240V and 2 120V). I realized quickly that the run was rather long to the farthest outlet in the garage so I started to research voltage drop and proper wire size. I have figured out that for the table saw I could use 12-2 romex pulled through conduit based on the calculation below:

Table Saw - 15A @ 240V 100ft away from panel with maximum voltage drop of 3%
(AMPS x FEET)/(PERCENT VOLT DROP x VOLTAGE) = VDI
(20 x 100)/(3*240) = VDI = 2.77 which is what leads me to 12-2 romex

I will also be running a dust collector which has max draw of 14 amps on a 15 amp circuit @ 120V. Same calculation for 15amp circuit is below
(15 x 100)/(3*120) = VDI = 4.16
This means I need 10AWG wire for the 120V circuits.

I will need two 120V circuits as I will be running the dust collector along with a planer (15A rated)

My questions are as follows:

Am I better off to run stranded wire for the 120V circuits? All Circuits? (I have heard it will deliver cleaner power to the equipment and in turn run better?)

Can i run 12AWG instead of 10AWG if I use stranded since the voltage drop is less?

Should I be running 20A 120V circuits if equipment is rated at 15A? If so do I calculate the wire gauge based on 15A or 20A?

Like most people I am on a pretty tight budget and I have plans to build a dedicated building in about 5 years so I am trying to do this on the cheap, but I don't want to sacrifice safety for a few extra bucks. Any help on this would be greatly appreciated.

 

[Gooch]

I am adding additional power to my attached garage in order to run my wood working equipment. The original plan was to run 6AWG to a 60amp sub panel, but after some investigating I realized this was going to get quite expensive. I have room in the 200 amp service panel in the basement so my next thought was to run three branches to the garage (1 -240V and 2 120V). I realized quickly that the run was rather long to the farthest outlet in the garage so I started to research voltage drop and proper wire size. I have figured out that for the table saw I could use 12-2 romex pulled through conduit based on the calculation below:

Table Saw - 15A @ 240V 100ft away from panel with maximum voltage drop of 3%
(AMPS x FEET)/(PERCENT VOLT DROP x VOLTAGE) = VDI
(20 x 100)/(3*240) = VDI = 2.77 which is what leads me to 12-2 romex

I will also be running a dust collector which has max draw of 14 amps on a 15 amp circuit @ 120V. Same calculation for 15amp circuit is below
(15 x 100)/(3*120) = VDI = 4.16
This means I need 10AWG wire for the 120V circuits.

I will need two 120V circuits as I will be running the dust collector along with a planer (15A rated)

My questions are as follows:

Am I better off to run stranded wire for the 120V circuits? All Circuits? (I have heard it will deliver cleaner power to the equipment and in turn run better?)

Can i run 12AWG instead of 10AWG if I use stranded since the voltage drop is less?

Should I be running 20A 120V circuits if equipment is rated at 15A? If so do I calculate the wire gauge based on 15A or 20A?

Like most people I am on a pretty tight budget and I have plans to build a dedicated building in about 5 years so I am trying to do this on the cheap, but I don't want to sacrifice safety for a few extra bucks. Any help on this would be greatly appreciated.

pulling romex in conduit is a major PITA, just run the romex as it is, or pipe it and pull single conductor.


your Voltage drop formula isn't what i've seen before, should be:

2KIL/CM=VD

K=Constant(copper 12.9, Alum. 22.3)
I=Current
L=length to load
CM=Circular Mills
VD=Volts dropped.

 

[chickenhauler]

Can't pull romex through conduit... You could use 12-2 on 20A circuits for all three, or if you're using conduit, just pick up THHN. You'll want to use 20A breakers, unless you like making the 100' run to reset them every time you load the saw a little lol.

 

[nehog]

...
My questions are as follows:

Am I better off to run stranded wire for the 120V circuits? All Circuits? (I have heard it will deliver cleaner power to the equipment and in turn run better?)

There is no such thing as 'cleaner' power with stranded wire.

Can i run 12AWG instead of 10AWG if I use stranded since the voltage drop is less?

Voltage drop is identical for stranded and solid wire.

Should I be running 20A 120V circuits if equipment is rated at 15A? If so do I calculate the wire gauge based on 15A or 20A?

Run as big a wire as possible. Using 10 AWG is always better than 12 AWG.

Like most people I am on a pretty tight budget and I have plans to build a dedicated building in about 5 years so I am trying to do this on the cheap, but I don't want to sacrifice safety for a few extra bucks. Any help on this would be greatly appreciated.

The difference between stranded and solid is installation ease, only. There is no difference as far as the electricity goes. Using larger gauge wire allows lower voltage drops, which is better for some things. Bog my table saw down, and it will trip a 20 amp breaker! That saw is much happier on a 30 amp circuit.

 

[sberry]

Also instead of running 2- 129's run a multi wire circuit. 12/3 wg. Even at that distance the V drop wouldn't be critical but I like a sub and larger wire, run it once and you are done.

 

[rwreuter]

couple of things....2 cents coming from an electrician.....

more than likely, when you are done you will find out that installing a sub panel would have been cheaper. install a sub panel (if you do, don't ad up all the devices and think you need a panel that large) a 60amp sub panel is more than enough.

you won't be running all of these tools at one time....so a huge sub panel isn't necessary.

in the long run the sub panel will serve you better, things change.



when building, a rule of thumb i use is "ugly lasts forever, cost is soon forgotten" i understand you are on a tight budget, but the cost when it is all said and done won't be too different. and in 2 years when you want to "add or change" something you will be kicking yourself for not installing it.


IMHO

 

[sberry]

Good advice and there will be a circuit that would support a welder if needed, reasonable air comp and even the 120V loads will be delivered on a heavy wire. I actually have 5 subs in my shop, it is 80X80 and it saved a gob of branch wiring as well as served some motor loads or support a welder if needed. Most of the recepts are 10 or 20 ft at most from the panel. Didn't have to over or under doorways for any major loads, both planned and additional.

 

[pattenp]

There is no such thing as 'cleaner' power with stranded wire. Voltage drop is identical for stranded and solid wire. Run as big a wire as possible. Using 10 AWG is always better than 12 AWG.

The difference between stranded and solid is installation ease, only. There is no difference as far as the electricity goes. Using larger gauge wire allows lower voltage drops, which is better for some things. Bog my table saw down, and it will trip a 20 amp breaker! That saw is much happier on a 30 amp circuit.

Is this correct? I thought stranded wire of the same gauge as solid has a higher amp capacity. My understanding this is because the electrons flow on the surface of the wire and stranded wire has more surface area than solid wire.

 

[rwreuter]

true, but in residential on 15amp and 20amp circuits is really doesn't matter. besides, you would have to change the way it connects to the receptacle. in many (AHJ) jurisdictions you can't land stranded wire under a screw (besides that, it is much more difficult to do so) and you defintely can't stab it into the back of a receptacle.

if i am running emt i like to pull stranded wire...it is ALOT easier of a pull.

 

[Alchymist]

Is this correct? I thought stranded wire of the same gauge as solid has a higher amp capacity. My understanding this is because the electrons flow on the surface of the wire and stranded wire has more surface area than solid wire.

Not at 60 Hz. You have to get into radio frequencies for skin effect to start. Another example of a little information ......

 

[theoldwizard1]

...
In the long run the sub panel will serve you better, things change.

When building, a rule of thumb i use is "ugly lasts forever, cost is soon forgotten" i understand you are on a tight budget, but the cost when it is all said and done won't be too different. And in 2 years when you want to "add or change" something you will be kicking yourself for not installing it.

+1 big time !!!!

 

[nehog]

Is this correct? I thought stranded wire of the same gauge as solid has a higher amp capacity. My understanding this is because the electrons flow on the surface of the wire and stranded wire has more surface area than solid wire.

The effect is called 'skin effect' and is apparent at high frequencies (RF) not at AC power frequencies.

Using stranded wire is mostly a labor saving idea... In high vibration areas it (stranded) can (big can) be advantageous but for anything you do in your shop think along the lines "Do I want to pull 12 or 10 solid or stranded?"

 

[mtne]

Strictly speaking stranded has more resistance per foot (chap 9 - tbl 8) but no one here will ever notice that functionally.

Definitely add a sub panel. You won't ever look back and ever think you choose poorly. Personally I prefer solid for anything 12awg and stranded for anything larger. And I avoid 14awg unless there's a specific good reason to use it.

While it's not typical, and most electricians avoid it, NM can be run in emt, rmc, pvc, and the like (334.15.B) to be protected from physical damage. Likewise mentioned in (300.4.B.2). Personally I would run 12awg to a box and splice, or just pipe everything given the chance. Also keep in mind that once you start putting cables in conduit the temperature corrections factors and ampacity derating really kicks in. That stuff is no fun to figure so most people don't............ but mostly NM is a PITA to pull in any conduit.