The Stovebolt Site Forums The Shop Area The Tool Chest Help Please! Electrical plans for my shop!

I am looking for advice.

This topic might bore some people. Sorry.
I have ZERO experience in wiring and electricity. Therefore I will hire an electrician to actually install the shop wiring. However, I hope to save a lot of money by installing the conduit myself.

Most electricians I've talked to don't have a grasp the master plan I have in mind.
The master plan includes compressed air lines, 220V outlets in all 4 corners of the shop, 100V outlets every 5 feet, LED lights, shelves at about 7' high, and at least 6 exterior outlets.

I have a plan in mind already, but the collective wisdom here usually gives me good ideas that I didn't think of.

LINK to pics and video.

Thanks in advance for your advice.

Jay

I'd suggest running a fairly large diameter piece of conduit around the perimeter of the entire shop, at about the level of the angle braces, and dropping off to workbench height with individual circuits using somewhat smaller conduit. All this can be surface-mounted with elbows and tees with cover plates for access for pulling the wire. Some electricians don't like to do it, but on any electrical wiring that I do my self, I have a habit of using wire one gauge larger than the electrical code specifies- - - -for instance, use 8 gauge instead of 10, 12 instead of 14, etc. Material cost is a one-time expense- - -voltage drop is forever!

Check your email- - -those power outlet strips make a lot of sense to me!
Jerry

I've just added another photo to the LINK.

There's no need to run separate conduit for the 110 and 220V circuits, they can share the same conduit, just by running additional wires in it. The electrical code has tables for how many wires can run in a single conduit of a particular size, so you or your electrician should check that to figure out what size the conduit needs to be. Otherwise your plan looks good. Like Jerry said, go with bigger conduit and conductors. PVC conduit and boxes are pretty cheap and pretty easy to install. Just takes a PVC cutter (like a shear), a knife to chamfer the cut ends and a can of glue. There's also a limit on the number of bends (3 90's IIRC) you're allowed to pull wire around, so be sure you have pull boxes in the right places.

I would suggest pointing the lights in a more downward direction.

If I use a single conduit, then I might design it like See Option #2.

It makes sense.

You could also go to an electrical supply store with your drawing and they can point you in the right direction They are a great source of the local code requirements. Your garage looks great!
I have mine enclosed for the winter and can now hopefully get some of the interior work complete. Need to complete my electrical, insulation, heat, drywall and paint. Spring I will shingle and do the siding.....and
plant some grass.....best of luck and have fun
Dan

To eliminate the number of bends (ref: klhansen), replace them with junction boxes. This makes it easier to trace shorts and power drops when and if they occur. Plus, more outlets can be added at a later time; just get a bigger junction box. Again, ensure box conforms with the number of wire junctions in it. Can also be of PVC.

Stewart

Jay, lots of good info here but I will add one comment.
When I wired my shop I put a drop every 6 foot. At the time I figured one receptacle would be enough in each box as I have a drop every 6 foot......wrong. Especially when I'm doing wood work and need more that 2 places to plug in a cord.
Luckily I used the big box so I went back later and added another receptacle to each box so I have 4 places to plug a cord into.
220--I have two but wish I had put a 220 receptacle at each garage door!

Alvin,
I agree. All of my 110V outlets will be 4 gang. (Is that the correct term for 4 outlets together in one box?). I’ll probably have 10 to 12 of them plus a few outside too.
I’ll have a 220 outlet in each corner of the shop. Plus another 220 feeding the lift. Plus three more 220 outlets on the outside of the building, one left, one rear (for the compressor) and one inside the lean-to.
I might even have a drop cord outlet hanging down in the center of the shop.

Definitely do that. A retractable cord that can be set at different elevations depending on where you're working would be awesome.
When I first started working on my truck, I had an extension cord laying on the floor and had to bend down and pick it up every time I needed to change tools. I was getting too old for that, so finally ran a cord down from the ceiling. MUCH nicer just reaching over to plug things in as opposed to bending down to the floor.

I have to question the need for 220v outlets all over the place. Most 220v outlets are installed for a specific piece of equipment that is normally parked in one spot (Lift, Compressor, welder, etc.). What portable equipment will you be using that requires that many outlets? Will all of them be the same amperage? I have a 220v 50a welder and a 220v 30a welder with one outlet for each at the welding table and on the rare occasion I need to move elsewhere in the shop I have matching 30a and 50a extension cords.

If I were you I'd lay out the outlet locations (painters tape on the wall) and have your licensed electrician tell you how he wants you to run the conduit in the building. With more than three circuits in a raceway you get into derating the ampacity of the circuits in that raceway.

Also, check with your local inspector to confirm PVC conduit is OK. It's prohibited to be used in areas where subject to physical damage, unless identified for such use. He may think your shop falls under that part of the code. I'd use EMT if I were installing it for you...

I WOULD put a 120v outlet between the doors, inside and out! That's the only location you won't ever block with a perminate piece of equipment and you'll use it ALL the time!

As for air, one hanging next to the center lift leg with 50' of hose will handle the entire shop. Maybe add one at the workbench, one at the sand blast cabinet and one outside between the doors. It you run the line up high, every time you drop down put the quick connect outlet on a Tee and install a 12" drop leg below the outlet TEE with a ball valve at the bottom so you can blow the accumulated water out from time to time. Don't forget some sort of an air dryer if you plan on sand blasting...they hate water.

Have your electrician price the entire install and then give you a deduct if you run the conduit, you may find the deduct is so small it isn't worth your time...cheaper and faster for him to do it all.

Where is the 100a main feed coming from? Is that panel/service capable of providing that much power to the shop?

Mike B

All good points.
I want a dedicated 220V outlet for each of the following.
Compressor (this 220V would be exterior)
Window AC unit
2 for the TIG welder (one in each front corner of the shop so I can use the welder on either side without an extension cord).
The lift will require dedicated 220V service.
Another 220V at the back right corner of the shop would be a luxury but would then give me access to 220V in all 4 interior corners of the shop.

Luxury
Adding an exterior 220V at the window AC unit location means poking a hole through the wall. The lean to will need 110V to trickle charge the boat battery. Adding a 220V next to it would be a luxury.

What Mike B said about the air drops is a good idea, but you can also just put his suggested drip leg and drain valve on just the last drop and install the ones closer to the compressor on an "arm-over" (tee pointing up and a couple of ells to the drop) and no drip leg. But to do that, be sure that the main slopes toward the end of the run. You also need a drip leg and drain valve near the compressor on the riser to the overhead mains.
As far as electrical outlets, they're like tools in that you can never have too many of them.

Haha! Good advice I’m sure. However, I’m light years away from installing an air compressor. I’ll likely bring air into the shop through the rear wall. I’m trying to plan the conduit so as to leave a clear path for future black pipe.

For the compressed air, there is no simpler or safer design than this:

TP Tools Tech Tip
TP Tools Air Lines Diagram

Black pipe from Home Depot (in standard lengths, and, they cut/thread custom lengths for free).
I got my 1/2" shut off ball-valves from Harbor Freight. They do not sell them anymore. Check eBay.

I never had moisture in the lines (never had to drain moisture from the separator).
Moisture is a killer if you use the air for painting.

I get brass housing ball valves from Home Depot. They usually have them on the shelf from 1/4" to 1" or larger.
Jerry

hello just wondering if you have made any head way on your shops elec.? pulling a permit or not? if you were closer id help you knock it out.feel free to contact me , I`ll help how ever I can . done this once or twice

I now have a permit. Final drawings are done. Problem I’m having now is finding an electrician who will come by to give an estimate. I have conduit benders for 3/4” and 1/2” and plan to hang the conduit myself to save money. Then have electrician pull the wires and install the breaker box.
Your offer is thoughtful. I’m trying not to go crazy. My impatience with trying to find a reliable “keeps his word” electrician is building.

Hey Jay, give coolwhip a nod and give me a call. I'm game for a days worth of work but I don't climb ladders anymore. What day you want me to show up? This way you want have to look for "keeps his word" amymore.

congrats getting thru permiting. sounds like you pulled a homeowners permit. a couple things I would like to point out to help minimize time,$ and frustration. 1. drawings/print our a guide line not wrote in stone how I get from a to b is up to me not necessarily the homeowner .100 amps but how many spaces ,up to them you get bare min. with 1 120v spare , or a 200 amp main lug panel 42 space .this is all general ie in the videolooks like pvc conduit could be 2" .if so great overkill for 100a but the highway is there for future upgrade. 2.conduit bending is math and a art. to help min. bending use mineral lax straps to secure pipe.the best pipe job is one where no pipe is bent.this is understood when you have to pull wire .be aware of takeup 5" on 1/2 , 6" on 3/4 .no more than 360 degrees total without setting a j-box. it goes on and on pm me with your phone number and I will help how ever I can . had surgery couple days ago on both arms difficult to type. merry x-mas

Coolwhip,
I sent you a PM.

Maybe I should get a 200A service box? That way I can add a heat/AC unit later?

Jay

Tim, thanks for reposting that TPtools link on air line systems. That definitely takes all the fuss out of design questions (at least it did for me). Very simple but lot's of options. One question, how did you attach the pipe to the walls (assuming walls structure is wooden, and not metal like Jays shop)? Did you use the TP brackets? Suppose you could use those metal conduit straps that would be much less expensive.

Allen,
My shop now has plywood interior walls. This was by design. Now I have a surface to mount my air pipe and electrical conduit. I can hang items on the wall. Insulation is sandwiched between the plywood interior and metal exterior walls.

Jay, I would highly recommend going with 200 A box up front, even if you use 1/2 of it initially . I recently added a dedicated 220 V for an A/C (which as nice a shop as you're building you will definitely want for those sweaty summer months). If I add anything else, I will have to add a sub panel, so wish I would have gone with a bigger panel up front.

I see Jay, thanks. You're going to have a nice setup when you get it all done. Appreciate you posting progress as we are learning with you. We're happy for you, but really simultaneously jealous !!!

Allan,

I think I used the brackets that Home Depot sells for the black/galvanized pipes?
galvanized tube/pipe strap/hangers

Updated video for those interested in my electrical conduit plans. I've spoken to Coolwhip and he passed along good ideas. The ideas on the video are my own and subject to change. This group has been a great source of ideas and I appreciate all the help.

Electrical conduit overview for the shop.

My web page with updates.
Jay

Jay,

I have a few questions;

Where is the garage incoming electrical feed coming from, your house or a new electric meter?

What size panel did you list on the permit?

Did you have someone do a load calculation to make sure everything is sized correctly?

You talk about 240v outlets like one size fits all, that is not the case. A 240v stick welder will need a 50amp circuit while a 240v MIG welder needs a 20amp circuit. Your 5hp compressor (just guessing size) will need 30amp wire fused at 70amp. So each need is really different. If I were you I'd upsize the EMT home runs to 1" and pull the 240v circuits into the pipe after you get the equipment so you get it right. Wires/circuits can be added later as long as the conduit is sized for it.

If you hired me to wire you garage, I'd be talking you into a 240v 50 and a 240v 20 between the doors and that's it, nothing else needed. Then I'd make up a 25' extension cords for each outlet/welder These cords would allow you to work anywhere in the shop and these outlets would be in a great central location that will never be blocked by anything. All the rest of you proposed locations are a waste of your money and I'd bet in the long run are never used. My shop is bigger than yours and I only have the welders setup in one area and I bring the work to the welder, not the other way around as I like to keep the sparks away from my storage shelves.

Mike B.

Thanks for this discussion gentlemen, I’m in the process of constructing a garage at my house in Maine where I’m gonna spend the revolution. They broke the ground before the snow fell to assist in the settlement of the ground once the cement is poured. Being a Tarheel boy it sounds good to me as I am unfamiliar with such things.I had given no thought to the placement of the electrical outlets save a 220 for my old Lincoln welder.this has given me much to think about.

mike b has all very valid points/concerns merry xmas everyone.

Mike B,
I have no idea what a load calculation is, so no, it has not been done. Looks like I need to visit the library and read about home wiring. My ignorance shows itself in all sorts of things!

The idea of 25 foot extension cords is not foreign to me, but I was trying to get away from things laying on the floor. Bending over to plug and unplug equipment is another issue. I’m not full of arthritis (yet), but I’ve been using a single drop cord to do all of my shop work thus far and it ain’t no fun.

My TIG/stick welder has a badge saying 52A. The lift is badged at 14.5A. The MIG is 110V but I will likely upgrade to a 220V one day. I like to weld.

I appreciate the advice given here. You are all very patient.

Even if an outlet is only used occasionally, it's nice to have a few options about where to plug in things like welders, etc. I look at things from a longer-term perspective than most professional electricians who have some very legitimate concerns about meeting electrical code requirements and that pesky thing called "making a profit" and "not starving to death"! Whenever possible, I like to use wire at least one gauge above what code requires. Electrical codes are MINIMUM requirements- - - - -voltage drop is forever, and what I spend up front on lower-resistance wire will probably amortize itself pretty quickly by making my equipment more efficient over the long haul.
Jerry

The more surface area for electricity to travel, the less heat it will generate. And we all know heat is bad.

Voltage drop.
True or false?
The longer the extension cord, the greater the voltage drop. (Assuming wire gauge and insulation stays the same.)

Or, is it dependent on amperage too?

True- - - - -the SMALLER or LONGER the conductor is, the more voltage loss there will be. Try putting out a house fire with a garden hose, compared to the hoses a fire truck uses. By going bigger with a conductor, there's less resistance, and more voltage gets delivered to the item that needs it. That's why 6 volt starters need BIG cables- - - -more of the battery voltage gets to where it needs to be. Ditto for bigger conductors in a shop wiring system.
Jerry

YES voltage drop is dependent on current, as in the amount of current used by the device. For simplicity sake check this link outvoltage drop
HRL is right though, bigger wire = bigger power, the longer it is the bigger it needs to be.

Assuming you have a good supply voltage at the panel board in your shop you would have to have really long runs to be worried about voltage drop. If you are really interested the NEC national electric code has guidance on calculations for this. Also the NEC provides for the wire size vs breaker size. My house is single story and about 100 ft long. I used 14 awg copper for all lighting and 12 awg for all receptacles. There is virtually no voltage drop at my longest run. I work for UL and only once in a Costco store did I have excessive voltage drop that affected my test. Sure it is possible but call your utility. Voltages have been increased over the years. Some people may remember 110 V. 120v is typical now. If you are in Canada the power runs are long and Canadian motor equipment must pass a test at 104v. One other important thing on wire size circuits are only supposed to be run at 80% capacity. So a saw that draws 16amps on a 20 amp circuit is fine. A saw that draws 18 amps on a 20 amp circuit should really be on a 25-30 amp circuit/10 awg copper. There is much more to all this. I have 5 large woodworking tools. I run all these 240/20amp. The motor runs cooler. So I have 5 240v circuits and 10 120v circuits. I install two 240v cord drops and wish I had installed 120 v cord drops too. I wish I had installed 1 50 amp circuit for a large welder. Some day. Interesting reading different thoughts. The more circuits the better its all about cost. As far as main breaker its hard for me to see an amature home shop use 200amps at one time. Even welding and a compressor running would not even be close.

As I’ve previously said, I want to wire the shop with numerous outlets for convenience. I’m not opposed to using an extension cord, but in my mind it’s not as convenient.
My shop will have the following tools and equipment.
Drill press 120 or 240V (can be wired either way)
MIG welder 120V
TIG/Stick welder 240V and label says 52A
Automotive lift 240V and 14.5A
AC window unit (probably 240V)
LED lights 120V and amperage is negligible
Hand tools 120V
Air Compressor (future purchase) 240V. I currently have 2 smaller portable air compressors and one is 120V and other is 240V.
Possible future central AC/Heat

99% of my welding will be done outside of the shop. However, I might want to occasionally tack weld something while inside the shop.

I'm accustomed to working in professional-level shops and/or BIG schools where there might be several people using high current draw equipment at the same time. For instance, the vocational wing at the high school where I spent most of the last 20 years of my working life had the following departments:

Wood shop
Body shop
Welding shop
Machine shop
Aircraft maintenance shop
Auto mechanics shop
Commercial refrigeration shop
Print shop
Electronics shop

There were TWO 50 HP air compressors running on 480 volts, with an automatic switching system that alternated between the two. Under high demand situations, it was not uncommon to find that someone had gone into the mechanical room and switched both control panels to "manual" mode so both compressors ran continuously. The machine shop had 10 each, 14" capacity lathes and big Bridgeport mills. The welding shop had 10 welding stations with 250 amp AC/DC machines, plus a couple of TIG machines, one MIG, and a plasma cutter. The electric bill for that department alone was in the thousands of dollars per month!

Go big or go home!
Jerry