Running a shop off a generator

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Forum topic by ladiesman217 posted 02-07-2012 08:07 AM 5361 views 0 times favorited 25 replies Add to Favorites Watch
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74 posts in 3210 days

02-07-2012 08:07 AM

Topic tags/keywords: workshop generator tablesaw

Hey all, I know this has been touched upon before but I would like to hear some more opinions on this…

I luckily have a detached garage that is ~60 ft from the house. Unfortunately, it has a very weak 15A line to it. That’s it. I cannot run a dust collector and saw at the same time..everything is dark and covered in dust at this point. I also happened to buy a PM 66 for a steal (full well knowing I did not have the power for this beast) and would love to get it running.

Now I spoke with an electrician and he quoted me $1400 to add a box, breakers, and dig and install the line to the garage to give me a 50 amp box. That’s a lot of money to me at the moment (just paid for a headgasket job on my Subaru). I had the idea that I could buy a generator and use it to power the saws, dust collector, etc instead of paying for the electrician-oh, and I don’t know how long I’ll be living here + I only use the machines a couple hours a week at most with my job taking all the hours of the day.

So what’s the verdict?

-- Rock Chalk Jayhawk!

25 replies so far

View JAAune's profile


1798 posts in 2312 days

#1 posted 02-07-2012 08:10 AM

The biggest expense might be the digging. I’m not sure on that but when I got power to my shop I shoveled out the trench myself and did the filling as well. You might want to check to see how much the cost comes down if you do the same. No sense in paying an electrician $50.00 an hour to move dirt.

-- See my work at and

View fussy's profile


980 posts in 3046 days

#2 posted 02-07-2012 08:20 AM

Nope! No can do. $1400.00 may seem kinda high to you, but the price of a generator capable of handling the load you will apply with just a saw, lights and dc would far exceed that price. Then you have to add the cost of gas and the rather steady maintainance requirements of a gas generator. The homeowner units sold at big box stores don’t have the huevos to pull the load without seriously underpowering and damaging your equipment.

Get other estimates, but If you’re serious, get a 100 amp sub panel. 50 amps would be a bare minimum. If you find that too stiff, have the electrician install wiring from your house big enough for 100 amps, put in a 100 amp box (you can find them used all over the place. Lots of people upgrade 100 amp to 200) and buy only the breakers you need now. You can add circuits later ass you need, and you can read up and do that yourself, iof you feel confident and proceed according to code. The digging and labor would be the same, just higher cost initially for the wire to the garage. Good luck.


-- Steve in KY. 44 years so far with my lovely bride. Think I'll keep her.

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Tyrone D

314 posts in 2328 days

#3 posted 02-07-2012 11:29 AM

I have 60 amps in my shop and it works perfect. I used to have 30 and I was tripping breakers all the time.
With gas prices and the cost of the generator I highly doubt it would be more economical than re-wiring your shop.

-- --Tyrone - BC, Canada "Nothing is ever perfect, we just run out of time."

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13603 posts in 3337 days

#4 posted 02-07-2012 12:31 PM

worst case
and a quickie

make a decent extension cord
(or buy a 10 gauge one)
and find a receptacle that can handle it
in the garage or house

with as little use as you are using it
switch from tool to tool as needed

a generator will eat you alive
and the noise will bring down the neighbors

-- david - only thru kindness can this world be whole . If we don't succeed we run the risk of failure. Dan Quayle

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1829 posts in 2385 days

#5 posted 02-07-2012 12:39 PM

Dig it yourself, it is good exercise. There is no magic to electricity. You can do most of the work and then pay the electrician for the things an electrician is really needed for. I put in a 100 Amp box in my barn, I ran all the circuits myself and then paid the electrician to inspect and do the final hookup. I only ended up paying the electrician for 1/2 hour work. This job was 7 years ago but I think the total cost was under $150. My back paid a different price for the digging however. 36” is real deep if you are digging by hand. However, there is a certain oneness with the world when your back is protesting the abuse you have put it to. Proverbs 31:7 would seem to apply here

-- Haming it up in the 'bash.

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255 posts in 2329 days

#6 posted 02-07-2012 12:52 PM

Do the work yourself. Don’t worry about how long you’ll be there, you’ll recoup expenses if you do sell. Go 100 amp sub-panel, the 1400 buck quote had more to do with labor than size of panel. Pay for inspection and certification. Go have a beer at the local pub, you’ll find a licensed elec. to inspect and sign off on it.

-- "The greatest pleasure in life is doing what others say you cannot do."-Walter Bagehot

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404 - Not Found

2544 posts in 2965 days

#7 posted 02-07-2012 04:24 PM

Could you hire a mini digger for the weekend and do the trench yourself? (It might even be fun).

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2630 posts in 2879 days

#8 posted 02-07-2012 04:31 PM

I just had a small (40 amp) backup generator installed: $5000. You won’t find a cheap generator that will be able to handle the current draw of your tools. I agree with what the other guys said about the sub panel: go for 100 amps, 50 amps won’t cut it.

-- Sometimes the creative process requires foul language. -- Charles Neil

View DS's profile


2917 posts in 2416 days

#9 posted 02-07-2012 05:17 PM

I suspect if you dig the trench and drop in the conduit, the price will come down substantially.
Paying electrician rates to dig holes is silly IMHO.
A weekend in your back yard with a shovel can save a lot of dough.

Pay him to do the electrical work. Do the rest yourself.

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

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57 posts in 2350 days

#10 posted 02-08-2012 12:10 AM

I went with 100amp service in my shop.I bought a black& decker.. home wiring book from home depo and materials.My inpections went fine and I learned another valuable skill.

-- Bill Byron Center MI

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125 posts in 2395 days

#11 posted 02-08-2012 12:26 AM

I live an hour away Ill give you a hand no charge. Hardest part is digging the trench if you wont go for a ditch witch, which would cost about $75

View Dallas's profile


3599 posts in 2483 days

#12 posted 02-08-2012 12:47 AM

If you want to run a decent shop, go for the 100a or better yet, have ConEd or whoever sink a new power pole and transformer.

In most states and municipalities it is legal for the home owner to do his own work without a permit.

If you have enough power coming from your main breakers to handle it, I can make you a great deal on some #2 copper. Or I think I have enough 2/0 to make it 120 feet.

Here’s the kicker… if you have a 200a service coming into your house and you add up all the circuit breakers, where are you going to get the extra power to run your shop? Are there 200a worth of breakers in the box? Is the line in capable of handling the loads you want to put on it?

Do you even know what the NEC requires for a service entrance in your area? How about the municipality?

Just randomly pulling power off your meter head is a prescription for disaster.

-- Improvise.... Adapt...... Overcome!

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5688 posts in 3304 days

#13 posted 02-08-2012 12:54 AM

I rented a trencher when I ran power to my shop from the house panel. Paid about $60 to rent it for half a day and dug a trench about 175 feet to my shop. Pay the electrician to do the rest unless you are sure you can do the witing yourself.

View Grandpa's profile


3259 posts in 2671 days

#14 posted 02-08-2012 01:09 AM

I rented a trencher…maybe $50 for half day…. and did my own. I paid the power company to make the final connection at the meter. They installed a breaker at the meter and attached to my line. That was $175 for the panel at the meter and a metal conduit up my meter pole. We have overhead power on REC (Rural Electric Cooperative) and the remainder is buried to the house and shop. The cost of a gen set then the fuel to operate it is expensive. Then the power would be marginal. As far as running a drop cord, the 10 ga. wire would carry 30 amps but you would have to have a 30A receptacle to plug it into. Most are 15A for 110V but you can get 20A and 30A at supply houses. Then the long run will have an amperage drop….so you will be better off to rent a ditcher and buy a panel. Talk to another electrician or even the same electrician with a plan in mind.

View BobM001's profile


388 posts in 2326 days

#15 posted 02-08-2012 07:36 AM

Here’s a chart for wire size ampacity for insulated conductors.
Ampacities of Insulated Conductors
From this chart you’ll see that for a 100 amp service you’ll need to run #3 copper in conduit or #0 direct burial aluminum. If you install a sub panel you’ll need 4 conductors. 2 hot, a neutral, and a ground connected at the panel. You might be able to get by with 3 if you drive a ground rod outside of the shop.
This chart will give you conduit size based on size of conductors.
Conduit sizing is determined by using table C.8 NEC 2008
I would bump up a size just to make the pulling easier. That would mean 1 1/2” PVC for (4) #3 copper conductors. Have a “LB” pull ell at the outside of the main stucture. One where you come up out of the ground and penetrate the side of the building, and one where you go up into the bottom of the sub panel. While you have the ditch open run a 1/2” conduit for a phone line or intercom.

So a pair of 1 1/2” 90 deg sweeps, enough pipe to get you from “A” to “B”. A couple 1 1/2” straight connectors. Let’s say (4) 1 1/2 “LB” 90’s and you’re good to go.

Have your conductors laid out on the ground and mark the ends with marker tape. Red, blue, for the hot, white for neutral, and green for ground

Remember the “electrician’s axiom”. One wire, hook it up. Two wires, screw it up. Three wires, pack it up.

Like others have said you can rent a ditch witch for a half day and have it done in nothing flat. A whole lot cheaper than $1500.


-- OK, who's the wise guy that shrunk the plywood?

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