Long Runs - 12/2 or Another Sub Panel?

[bad_idea]

I have a 30x40x12 stick built garage I built about 5 years ago. It is 10' from the side of the house. The main power panel is conveniently located on the corner of the house. I installed a 90 amp sub panel in the garage with 2-2-2-4 MHF in 1 1/2" conduit to the main panel on the side of the house. I have a couple circuits for lighting, 120v outlets, welding machines, and the air compressor (240v). Most of this stuff is all on the same side of the garage as the 90 amp sub panel. The sub panel is maybe half full.

I am not adding in more circuits on the far side of the garage for wood working tools - planer, jointer, table saw, etc. My question is: should I run individual circuits off of the sub panel to each component, or should I run another sub panel off of the sub panel for these items? To get to the far side of the garage is ~60' of cable length. My first thought is the cost to go that distance with cable capable of feeding a 60 amp sub panel would be less than routing a bunch of 12-2 romex to feed the circuits. My second thought is voltage drop would be considerably less routed through the 60 amp sub panel to the 90 amp sub panel to the main panel.

Thoughts? Cost effective is a consideration, but quality install that will feed the tools well is first priority. This is my home shop, where maybe someone else be running a piece of equipment while I run another.

 

[mm08822]

Since it's a seperate bldg it needs 1 feed. Run the sub panel to a central location inside the garage.

It will need to be a 4 wire feed and have 2 grd rods also.

ETA: misread location of 90a sub panel.

Hopefully you have 4 wire feed and 2 rods to it now.

 

[mike93lx]

Voltage drop won't be different if the wiring is sized properly.

I'd put the second sub panel in. It's cheaper and the runs will be easier.

4 wire, separate neutrals and grounds, no bond on the neutral. Same as what you should have for the 90a

 

[mike93lx]

Since it's a seperate bldg it needs 1 feed. Run the sub panel to a central location inside the garage.

I will need to be a 4 wire feed and have 2 grd rods also.

The 90 is already there, this would be a sub off that sub

 

[mm08822]

The 90 is already there, this would be a sub off that sub

Oops, I thought the 90 was with the house.

A second sub in the garage wouldn't hurt anything. Strategically locate it if you do it.

 

[thunderskunk]

So… the equipment is being installed in the same garage as the sub-panel or is this a new building we’re talking about? If you have room in that box for more circuits, put in more circuits. If you’re never going to run two tools at once, you just need more outlets, and it could just be one circuit. If that existing sub panel is an atrocious mess, another sub might keep things cleaner. I have the same size garage and run similar equipment; grinders, welders, compressor, etc. 12-2 does just fine for all of my circuits across the building.

A 50A sub panel costs $100, the main wire might cost $100, and if you have five tools each with a circuit, maybe $100 worth of romex, $30 per breaker, etc. Or, $60 worth of romex for one more circuit with five outlets, no sub panel. I don’t think the cost is all that much, but hey, that’s money I don’t think you have to spend if you don’t want to. Or just use 10-2. See snip.

 

[bad_idea]

Voltage drop won't be different if the wiring is sized properly.

I'd put the second sub panel in. It's cheaper and the runs will be easier.

4 wire, separate neutrals and grounds, no bond on the neutral. Same as what you should have for the 90a

I do indeed have a 4 wire, separate neutral and ground, no bond on neutral setup on the 90a with ground rods. Good to know I would need to run the same 4 wire setup from the 90a to a 60a across the shop.

Cheapest wire to get that done? I found (75') 6/3 Romex at Lowe's for $402?! Amazon has (75') 4-4-4-6 SER aluminum cable for $161-179 depending on brand. Cable will be routed through wall cavity, protected.

 

[bad_idea]

So… the equipment is being installed in the same garage as the sub-panel or is this a new building we’re talking about? If you have room in that box for more circuits, put in more circuits. If you’re never going to run two tools at once, you just need more outlets, and it could just be one circuit. If that existing sub panel is an atrocious mess, another sub might keep things cleaner. I have the same size garage and run similar equipment; grinders, welders, compressor, etc. 12-2 does just fine for all of my circuits across the building.

A 50A sub panel costs $100, the main wire might cost $100, and if you have five tools each with a circuit, maybe $100 worth of romex, $30 per breaker, etc. Or, $60 worth of romex for one more circuit with five outlets, no sub panel. I don’t think the cost is all that much, but hey, that’s money I don’t think you have to spend if you don’t want to. Or just use 10-2. See snip.

Equipment is in the same garage, 60' away 'as the cable routes'. I installed the 90a sub panel, it's fairly clean. I routed all of the cable from the top of the panel, down one side and up the other to allow for future changes or repairs (commonly done shipboard). I think you are right, looks like the cost to route the bigger cable will take many more circuits to make it cost effective.

Looks like I can buy (250') 10/2 Romex and run (4) more 20 amp circuits across the garage for $300. A sub panel would cost around about double that to run, but would support a lot more circuits.

 

[Shiftless]

Looks like I can buy (250') 10/2 Romex and run (4) more 20 amp circuits across the garage for $300. A sub panel would cost around about double that to run, but would support a lot more circuits.

If you run 4 more 20 amp circuits to the other side of your garage for woodworking or whatever, I can’t imagine needing more. You could have 4 machines running simultaneously and still be fine. You don’t plan to have more than 4 other people all working with you running machines at the same time do you?

 

[mike93lx]

I do indeed have a 4 wire, separate neutral and ground, no bond on neutral setup on the 90a with ground rods. Good to know I would need to run the same 4 wire setup from the 90a to a 60a across the shop.

Cheapest wire to get that done? I found (75') 6/3 Romex at Lowe's for $402?! Amazon has (75') 4-4-4-6 SER aluminum cable for $161-179 depending on brand. Cable will be routed through wall cavity, protected.

The #4 Al SER is rated for 55a, so you can breaker it at 60a.

You won't need that much power, though, since you can't have 60a worth of machine running at one time. I bet you could install a 30a feed and it would work.

That said, another way to do this could be Multi Wire Branch circuits, if everything is 120v. Two runs of 12/3 gives you four 20a 120v circuits

 

[Metal-Marc]

I bet you could install a 30a feed and it would work.

Two runs of 12/3 gives you four 20a 120v circuits

That's what I'd do for a one man shop. Both would work, but I'd run two runs of 12/3.

 

[pbon]

I would probably just buy a 250’ roll of 12/2. That should get you 4 outlets 20A each. If you need 240V on the other side, I would probably do the subpanel. I am just a DIYer not an electrician but I have run a few thousand feet of wire.

 

[dave*99]

I am not adding in more circuits on the far side of the garage for wood working tools - planer, jointer, table saw, etc.

Do you have these tools already? 120V versions of those tools always left me wanting in terms of performance.
Mine all run on 240V. Mostly older Delta stuff. Pretty reasonable on the used market. A single 20A circuit can supply them all. Unless you plan to run them simultaneously.

 

[fitter30]

60' 120vac 15 amp load is good Under 3% voltage drop

Voltage Drop Calculator

Calculate voltage drop in AC or DC circuits, plus learn the formulas to calculate voltage drop for single-phase and three-phase systems.

www.inchcalculator.com

 

[Dagny]

It would be hard to find an electrician that would recommend a sub panel in a building that size.

 

[JohnX14]

I'd keep it simple and run 3-4 20 amp circuits off the 90 amp subpanel that is in the building. As others mentioned, you are only using 1 or possibly two tools at a time. Run 3-4 individual circuits and any one can be converted to 240V. 60' isn't far. Most of the new houses I wire have home runs longer than 60' to more than half of the circuits in each house.

 

[sparky 1971]

30X40 isn't very big and 60' of wire isn't very long. My shop is 30X40 and I see no reason for a second panel.

 

[dave*99]

Not sure I can think of a need for 4 circuits @ 120V and 20A in my wood shop. I might do it in the OPs case but: While my machines are on 240, still what can I do in a 1 man shop? Dust collector and a table saw? Router and a shop vac?
I have 240 circuits for the dust collector and another for the machines. I also have 2 circuits @ 120V and 20A with alternating receptacles around the room.
I won’t lie. I do have a separate 20A circuit for the stereo. I can really sand smooth with Pink Floyd shaking the room.

 

[BurtEggley]

To the OP, maybe clarify how many circuits @ what voltage / amp you intend to install, and what will plug into each one.

I will say that in this house, the longest 123V 15A run has maybe 4 receptacles and a front door light on it. Beginning to end, it is about 60 - 70 feet long from the panel, and properly sized for the amperage. If a full load, like a hair dryer is plugged in, by the time one gets to the end receptacle on the run, the voltage has fallen to about 108V. The house was built in a time when those receptacles would only have been used for small table lamps, a clock, maybe a radio, or small stereo, etc.. If i was going to use electric motors in table saws etc., at that distance, I would go one size better on wiring if the runs are to be that long. My electrician checked all the wiring on our circuit and the drop in voltage is just a function of resistance over distance. The problem with many motors is that as the voltage falls, many motors will compensate voltage loss by pulling more current. That will shorten the life of motors.

 

[cgrutt]

If it were mine I'd want at least two 30A 220v circuits on that side of garage for a wood shop wouldn't that require at least 10GA wire min? Even if you don't have them now a cabinet saw and dust collection system don't seem out of reach. Maybe even another compressor... I had a small woodworking shop (shed really) and had three 220v circuits one each for my table saw, band saw and dust collection. A couple of 120v circuits as well for smaller tools.

ETA I forgot about the heater (electric baseboard) but believe that was a 20A 220V circuit, so I my small shop there were four 220V circuits in total. Plus a couple 120V circuits does your existing panel have space for that?

 

[Max]

If it were mine I'd want at least two 30A 220v circuits on that side of garage for a wood shop wouldn't that require at least 10GA wire min? Even if you don't have them now a cabinet saw and dust collection system don't seem out of reach. Maybe even another compressor... I had a small woodworking shop (shed really) and had three 220v circuits one each for my table saw, band saw and dust collection. A couple of 120v circuits as well for smaller tools.

ETA I forgot about the heater (electric baseboard) but believe that was a 20A 220V circuit, so I my small shop there were four 220V circuits in total. Plus a couple 120V circuits does your existing panel have space for that?

I agree with you. My dust collector, table saw, and planer are all 240V 30 A and they are all 3HP motors. My jointer and bandsaw are 2 HP if I remember right and also 240V.

 

[PCustoms]

I pulled a sub in my 50' shop because:

-Access back to main panel was kind of a PITA
-Needed several 240v circuits (saw, planer, jointer, DC) very close to sub.

 

[pbon]

I will say that in this house, the longest 123V 15A run has maybe 4 receptacles and a front door light on it. Beginning to end, it is about 60 - 70 feet long from the panel, and properly sized for the amperage. If a full load, like a hair dryer is plugged in, by the time one gets to the end receptacle on the run, the voltage has fallen to about 108V.

I had the impression the OP would be doing home runs with 12/2, not 60-70 feet of 14/2 with 4 outlets along that span. This could make a difference.

To me, the bigger question is the 120v versus 240v need. The subpanel allows both options but requires 60 feet of expensive 6/3. Have to weigh that cost versus 1 or 2 runs of 10/3 to 240v outlets plus 2 runs of 12/2 to outlets. The OP has to dial in his needs. I liked the comment from another one man shop woodworker who said he cannot really use more than two 240v at once. I liked options that allow future upgrades, like trading 120v machines for 240v machines.

 

[PCustoms]

I had the impression the OP would be doing home runs with 12/2, not 60-70 feet of 14/2 with 4 outlets along that span. This could make a difference.

To me, the bigger question is the 120v versus 240v need. The subpanel allows both options but requires 60 feet of expensive 6/3. Have to weigh that cost versus 1 or 2 runs of 10/3 to 240v outlets plus 2 runs of 12/2 to outlets. The OP has to dial in his needs. I liked the comment from another one man shop woodworker who said he cannot really use more than two 240v at once. I liked options that allow future upgrades, like trading 120v machines for 240v machines.

4 runs at 60' of $0.80/ft wire is more then a single run #6 SER. Add the cost of a small sub and it's probably equal cost, but added versatility

 

[mm08822]

4 runs at 60' of $0.80/ft wire is more then a single run #6 SER. Add the cost of a small sub and it's probably equal cost, but added versatility

If future needs keep changing/adding in that one area of the shop, then the sub panel makes the future electrical work short and sweet.

 

[pbon]

4 runs at 60' of $0.80/ft wire is more then a single run #6 SER. Add the cost of a small sub and it's probably equal cost, but added versatility

250’ of 12/2 is $145 on Amazon, which is $0.58/ft.

 

[PCustoms]

250’ of 12/2 is $145 on Amazon, which is $0.58/ft.

Most people don't buy their wire off Amazon. Who is DMNI?



Looks like it's $165 at the orange store. I used wire and cable pricing as it was fastest to lookup. Splitting hairs, price is about equal but a sub givers more future options IMHO

 

[kngelv]

Pictures would help.

James

 

[PCustoms]

Pictures would help.

James

I assume this is a joke

If not, how?

 

[theoldwizard1]

About 40 years ago, I was helping a neighbor remodel his kitchen. Both of out house were built in the 1950s and still had fuse boxes. He want more kitchen circuits but did not want the expense of replacing the fuse box with a breaker panel to gain more slots. The original fuse box had a separate 240V fuse "block" for a now removed electric stove.

(Likely not code ...) We installed a sub-panel in the back of the new pantry cabinet and moved the stove cabling over to it. Ran all of the new circuits from there. Changed the cartridge fuses to the appropriate size for the sub-panel.

 

[kngelv]

I assume this is a joke

If not, how?

Over 99% of the people on here are amateurs in regards to properly running electrical in a shop. Pics of the sub-panel location and where he wants to put outlets might help with advice.

James

 

[wyliesdiesels]

I do indeed have a 4 wire, separate neutral and ground, no bond on neutral setup on the 90a with ground rods. Good to know I would need to run the same 4 wire setup from the 90a to a 60a across the shop.

Cheapest wire to get that done? I found (75') 6/3 Romex at Lowe's for $402?! Amazon has (75') 4-4-4-6 SER aluminum cable for $161-179 depending on brand. Cable will be routed through wall cavity, protected.

I would never buy wire on amazon unless it was sold by and shipped by amazon.... too many 3rd party fraudsters on amazon

 

[BurtEggley]

I am now adding in more circuits on the far side of the garage for wood working tools - planer, jointer, table saw, etc.

Maybe start by making a list of the specific equipment that will be used, and then looking at the specification plates on them to see what they use / require. Then do the math on wiring. If cost were not a concern, then one could just add more power capacity than needed.

 

[Bert_]

Zero reason for another panel in that size building. Even if the material cost makes sense it will take way more time to install and wire a panel.

Last summer I wired a shop, 120x120 20-ft sidewalls. I put in two panels but they're right next to each other.

 

[PCustoms]

Zero reason for another panel in that size building. Even if the material cost makes sense it will take way more time to install and wire a panel.

I drilled 1 hole through my joists and ran a sub.

Had I ran individual wires it would have been 2-3 holes. Now that I have a ceiling up I can't run any more wires back to the main panel.

Ymmv