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Forum topic by Let_that_saw_eat posted 08-08-2017 10:07 AM 650 views 0 times favorited 19 replies Add to Favorites Watch
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Let_that_saw_eat

13 posts in 506 days


08-08-2017 10:07 AM

Topic tags/keywords: question resource

Hello Everyone,

The time has come to update my 100 amp service to my house, and along with it have a proper source of electricity for the garage. I have been vastly limited to what i can do and which tools i can use due my current service line.

I am looking for recommendations for my garage/shop and installing adequate power for my future work space, how many 220 outlets, outlets per foot, etc. My garage is 30’x60’ but currently i am only using 10’x20’ for woodworking due to limited space with storage and would like to dedicate a solid 30’x20 in the future.

I plan to buy a cabinet TS (220), a planer for sure, bandsaw, heat source, and plethora of hand power tools. To run a new line from the house to the garage will be 20’ and was wondering if anyone knew anything about a secondary box or subpanel in the garage and what size wire. I’m quite sure my electricians will tell me one thing but I was wondering if anyone learned the hard way or wish they went bigger or smaller with their components.

Any help is greatly appreciated!


19 replies so far

View hotbyte's profile

hotbyte

989 posts in 2816 days


#1 posted 08-08-2017 11:08 AM

A few years back we had A/C installed after 20+ years in middle Georgia using window units. We have a 150amp house panel. I also wanted a sub panel in shop. Rather than replace/upgrade house panel, electrician installed a new meter base that allowed 150 to existing house panel, 100 to A/C units (5 ton downstairs and 3 ton upstairs) and 100 to shop. It was much cheaper than replacing house panel with one large enough for new a/c and shop.

View Fred Hargis's profile

Fred Hargis

4771 posts in 2334 days


#2 posted 08-08-2017 02:01 PM

My last 2 (detached) shops and the current all had the same setup, the house had a 200 amp panel, and the shops were 100 amp subs off it. All my big tools are 240V, and the TS and DC are 5 HP. I’ve never been short on power, and I even have a welder (60 amp outlet) I use occasionally. hat is what I recommend you go with as well….

-- Our village hasn't lost it's idiot, he was elected to congress.

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WhyMe

910 posts in 1401 days


#3 posted 08-08-2017 02:56 PM

Asking this question is going to get you a lot of guessing. You really need to do load calculations to determine the size of sub feed that you need. Depending on the load calculation you may only need 60A, or maybe more, like 100A, or even more, 125A. I have 60A to my shop and do just fine since I’m one person and only run one tool at a time, plus a dust collector and a space heater or window A/C, plus lights.

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Srini

29 posts in 620 days


#4 posted 08-08-2017 03:14 PM

I had the same problem with my garage. The builder put only two 110V outlet, that too for 15 amps circuit. Currently I am upgrading it myself. My main panel in the basement was installed for 200 amps service when house was built. I am drawing 2-2-2-4 line to feed 100 amps new sub-panel in the garage.

Regarding number of outlets, I am yet to decide. My immediate need is for 240V 20amps circuit.

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Let_that_saw_eat

13 posts in 506 days


#5 posted 08-08-2017 03:31 PM

Thank you everyone for your input. I guess I’m leaving out a few key factors.

First we have overhead service with overhanging old growth trees so the buried line is a must. Not comfortable waiting for the next storm to take it out.

Second, I recently did some research on my panel in the basement. Just google search “Federal Pacific STAB-LOK.”

This box is the Hindenburg of Panels.

View magaoitin's profile

magaoitin

246 posts in 790 days


#6 posted 08-08-2017 04:35 PM

Like WhyMe said, be prepared for a ton of unique answers to this question, and probably more detailed info that you would ever want to know about electricity.

Load wise, a 60A subpanel is sufficient for a single person to use a shop, unless you plan on expanding use a big piece of equipment like a full sized welder in the middle of winter with an electric heater going. Living in Wisconson you probably need to dedicate a 30A circuit for electric heat, or will you have a wood stove or gas? The fact that you are thinking of a 240V tablesaw now, will probably lead you to deciding on a minimum of a 100A sub.

The cost difference of a 100A sub vs a 70A is about $15-$20 at Menards so the bigger the better. The biggest piece of planning is on the number of 220V-240V pieces of equipment you will have. Most 60A or 70A subpanels will have 4-6 slots. I HATE having to unplug one piece of equipment to use another, so that heavily influences my planning.

Here is one example using a pretty standard 100A subpanel with 6 slots ($45 at Menards)

(2) slots Table saw – 240V – Double Pole 20A-30A breaker takes (2) slots
(1) Slot Heater – 20A-30A
(1) Slot Lighting 15A
(2) slots Common outlets 20A – For a 30’x30’ I suggest 2 dedicated circuits but this will be based on local code. Your City might allow 4 receptacles on a single circuit or maybe 6. IDK. It will give you between 8 and 12 receptacles spread around.

Again it will be based on your local City (or municipal) code, but you might be able to put multiple 240V receptacles on a single circuit, if they are all the same amp rating, but this gets tricky.

If your code will allow it, I would look at a 125A panel with 12 spaces. It would give you room to expand in the future and at least to have 2-3 dedicated 240V cicuits along with a couple 120v spares.

I just finished my shop last year (30’x30’) and went totally overkill on power if you want a laugh at what overkill is, take a look at my blog post on wiring my shop. I figured the cost of running a sub panel off from my main vs a dedicated 200A main just for the shop and it ended up being about break even cost, so I didn’t do the sub.

I put a receptacle about every 2’ along (3) walls so I have around 34 outlets with (2) per circuit, with (2) 240V on each wall.

Think about future expansion too. I decided to put my electrical chase at 48” AFF, behind a 12” tall removable MDF panel. This puts the outlets at a continent height for me, plus I am not tearing out drywall or cutting needless holes in plywood sheeting when I want to change where a 240V outlet needs to go.

Here is my blog post on the electrical wiring I did. Like I say its overkill, but might give you some ideas or a good laugh.

http://lumberjocks.com/magaoitin/blog/93098

-- Jeff ~ Tacoma Wa.

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magaoitin

246 posts in 790 days


#7 posted 08-08-2017 04:39 PM

And Please post pictures of your build. I think most of us love to read and look at photos of what others have gone through for their passion. I looked through hundreds of blog posts on shop builds before I started mine.

-- Jeff ~ Tacoma Wa.

View Fresch's profile

Fresch

93 posts in 1761 days


#8 posted 08-08-2017 05:18 PM



Thank you everyone for your input. I guess I m leaving out a few key factors.

First we have overhead service with overhanging old growth trees so the buried line is a must. Not comfortable waiting for the next storm to take it out.

Second, I recently did some research on my panel in the basement. Just google search “Federal Pacific STAB-LOK.”

This box is the Hindenburg of Panels.

- Letthatsaw_eat

Most of what you read was for the commercial panels you have a load center, but I would junk it, breakers cost a lot and hard to find. The stabs never worked per design, was to heat up at stab and expand only they just fall out. Get an electrician to do a load calculation or you can, remember 100amps is really 200amps of 120volts, 200a is 400a. Count load not breaker size.

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Fresch

93 posts in 1761 days


#9 posted 08-08-2017 05:26 PM

200a new for house, 100a 30/60 space as sub. ($100), both load centres same brand/ style so breakers work in both.

View Srini's profile

Srini

29 posts in 620 days


#10 posted 08-08-2017 06:40 PM


Here is one example using a pretty standard 100A subpanel with 6 slots ($45 at Menards)

Even better deal on sub-panels here https://www.lowes.com/pd/Eaton-24-Circuit-12-Space-125-0-Amp-Main-Lug-Load-Center-Value-Pack/3027147

12 spaces topped with 5 free 20 amps single pole breakers!

-Srini

View WhyMe's profile

WhyMe

910 posts in 1401 days


#11 posted 08-08-2017 07:12 PM


I had the same problem with my garage. The builder put only two 110V outlet, that too for 15 amps circuit. Currently I am upgrading it myself. My main panel in the basement was installed for 200 amps service when house was built. I am drawing 2-2-2-4 line to feed 100 amps new sub-panel in the garage.

Regarding number of outlets, I am yet to decide. My immediate need is for 240V 20amps circuit.

- Srini

If the 2-2-2-4 is aluminum it’s only good for up to 90 amps. If 2-2-2-4 copper, you’re okay for up to 115 amps.

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Srini

29 posts in 620 days


#12 posted 08-08-2017 08:50 PM


If the 2-2-2-4 is aluminum it s only good for up to 90 amps. If 2-2-2-4 copper, you re okay for up to 115 amps.

- WhyMe

I have not seen 90 Amps breakers. Do we get them? Is it code violation to protect 2-2-2-4 aluminum SER wire using 100 amps breaker at the input end?

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Fresch

93 posts in 1761 days


#13 posted 08-08-2017 09:21 PM

A real electrical supply house.

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WhyMe

910 posts in 1401 days


#14 posted 08-08-2017 09:55 PM


If the 2-2-2-4 is aluminum it s only good for up to 90 amps. If 2-2-2-4 copper, you re okay for up to 115 amps.

- WhyMe

I have not seen 90 Amps breakers. Do we get them? Is it code violation to protect 2-2-2-4 aluminum SER wire using 100 amps breaker at the input end?

- Srini

90 amp breakers are available. Per the NEC it is a violation to protect #2 Al as a branch feeder with a 100A breaker.

View mrg's profile

mrg

786 posts in 2840 days


#15 posted 08-08-2017 10:03 PM

Is your garage attached or detached? How far is the panel? Most homes now days easily need the 200 amp service since most panels are close to full in older homes. That would decide rout to take.

-- mrg

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