Nate’s longterm tiny shop build

[N-Smooth]

I’m not sure if we have a sparky on here or not but I’m betting you all have some advice either way. Basically it’s looking like our detached garage build 24x26 is going to get started here in the near future. I’m only having the footings/foundation poured for now but still- progress!

My question is in regards to the electrical I’m going to run out there. I ran a 2” conduit from below the main power box on the side of our house in preparation for this, before the RV pad was poured. It’s shown, stubbed up obnoxiously high in the picture below.

Option 1: Run the conduit like the green shows, to the back of the shop, preferably outside? It would have to run through the footings in two places and underneath the floor of course.

Option 2: Run it like the purple shows, to the side of the shop and put it in front or behind the man door. This way it will be under the driveway still but the side of the shop will not be concrete so that part is good, I guess. That run will require 360 degrees of “sweep” which is the maximum of bends in conduit from what I’m being told. There is a sweep into the ground now and it would require 3 more to complete it.

I really don’t know a lot about electrical for this use so I’m open to suggestions. I also have additional questions about if I need a ground wire in the footings and anything else you all could think of to help me out.


TIA!

 

[RustEoldtrux]

My only suggestion is to avoid running anything under any concrete: floors, driveways or foundations. If you have any problems with the incoming power, you may have to excavate the conduit.

 

[N-Smooth]

My only suggestion is to avoid running anything under any concrete: floors, driveways or foundations. If you have any problems with the incoming power, you may have to excavate the conduit.

I wish that was possible but it’s already under a solid 40’ of concrete probably. That’s one of the reasons I’m debating if it matters having it under the shop too

 

[Pike2350]

I would sweep around the side. It is the gray plastic conduit? What size service are you running?

You can heat it up to get more gentle bends in so you end up with more of a 45* out of the existing concrete and another 45* to go around the shop corner.

You shouldn't need a ground out there since you are running from main to aub. It should be able to be grounded at the main..

I am not a sparky so take it for what it's worth. I see no be efit of going through footings and under the shop floor other then shortening the wire run....but that comes with risk of having ro rip it out in the very rare chance it has issues.

 

[N-Smooth]

I would sweep around the side. It is the gray plastic conduit? What size service are you running?

You can heat it up to get more gentle bends in so you end up with more of a 45* out of the existing concrete and another 45* to go around the shop corner.

You shouldn't need a ground out there since you are running from main to aub. It should be able to be grounded at the main..

I am not a sparky so take it for what it's worth. I see no be efit of going through footings and under the shop floor other then shortening the wire run....but that comes with risk of having ro rip it out in the very rare chance it has issues.

That’s what I’m leaning towards as well. 220v so I can run the welder and maybe even do a RV plug. I also expect I’ll be running some wires out from that panel to yard lights, gazebo ceiling fan etc. Yes, gray 2” sch40. The stubbed part is just sun-bleached white. Good call on the heat gun, I really can do less drastic bends. The wire run will actually be longer if I go straight through the shop so shortening it is another benefit. I’m also not against pulling wire before adding the last sweep up out of the ground. I was just chatting with my neighbor and he said pulling wire through 3 sweeps really sucked for him.

 

[Pike2350]

What amp sub are you doing?

I have seen the cheat where you tie a string to the wire, then to a ball wrapped in soft cloth around it to basically fill the pipe and use a vacuum to suck it through

I am guessing with a 100amp sub (would need 2awg wire) it may not be the easiest pull..but still doable.

 

[N-Smooth]

What amp sub are you doing?

I have seen the cheat where you tie a string to the wire, then to a ball wrapped in soft cloth around it to basically fill the pipe and use a vacuum to suck it through

I am guessing with a 100amp sub (would need 2awg wire) it may not be the easiest pull..but still doable.

Haven’t gotten that far yet. My dad said to do a ball or a rag and suck a string through as well. Honestly I think I’d try and rent a power fish tape or something. Either way I’ll definitely go overkill on the wire size.

 

[Herzog]

I'm a fan of the shortest distance, but being under all that crete doesn't make me happy. But if the conduit is good stuff, you should be fine...

Otherwise, lots of lube ( ) and a strong wire puller

 

[Herzog]

Haven’t gotten that far yet. My dad said to do a ball or a rag and suck a string through as well. Honestly I think I’d try and rent a power fish tape or something. Either way I’ll definitely go overkill on the wire size.

Use the blown in string to then later pull a much better "wire puller" through.

 

[Pile of parts]

That’s what I’m leaning towards as well. 220v

 

[Herzog]

Also - what amp service do you have to your house?

 

[Herzog]

Another thing you could consider - if I'm reading your photo right - is go into the building at the stubbed out conduit and up into the attic, then back down to your final panel where you want it.

 

[N-Smooth]

Also - what amp service do you have to your house?

I think it’s 100.

EDIT: one big 150A breaker so I guess 150…?

Another thing you could consider - if I'm reading your photo right - is go into the building at the stubbed out conduit and up into the attic, then back down to your final panel where you want it.

So the stubbed up conduit is pretty close to the middle of where the overhead door will be. We just ran it clear of the RV pad and stopped there.

 

[Mouse]

Herzog is hitting the right things. We pulled 140 ft of 3/0 aluminum for my shop this spring, through 2" conduit. I couldn't get the job done by myself, I had to get help. 2 days to get it done. Less turns are better, and big sweeps for turns will make it easier. I'm glad its done now

 

[Herzog]

I think it’s 100.

EDIT: one big 150A breaker so I guess 150…?

Cool, I think you'd be fine to run a 50A sub panel then, depends on the usage of your home. If I recall, my last place was 150A at the house and 50A at my shop sub panel and I ran a big air compressor (22A max) and welder (~30A max depending on use) but rarely at the same time. A few times I did and tripped the breaker but no big deal, that circuit was on a 30A circuit with two other other 20A circuits being used for outlets and lights.

My current place, the guy who built it works for the local power co-op and he put 300A at the house so I have a full 100A at the shop which has been pretty rad so far... but places up here are mostly heated via woodstove/fireplace and supplemented with electric baseboard or cove heaters so it's not uncommon to see higher amp services at a normal home.

So the stubbed up conduit is pretty close to the middle of where the overhead door will be. We just ran it clear of the RV pad and stopped there.

You could always just change where that stubout comes up then (which I think is your plan now that I see it) and still just head up into the attic where it makes sense so you're not pulling a ton underground. Just an option! Stoked for you to get a shop going!

 

[Herzog]

Herzog is hitting the right things. We pulled 140 ft of 3/0 aluminum for my shop this spring, through 2" conduit. I couldn't get the job done by myself, I had to get help. 2 days to get it done. Less turns are better, and big sweeps for turns will make it easier. I'm glad its done now

Yea that's the other thing to make sure you watch for. When you pull the legs, if you use aluminum you have to use a thicker gauge than you would with copper. And make sure you coat the exposed ends at the lugs with anti-corrosion goop. Super important!

 

[N-Smooth]

So I just looked at the meter now that it’s not dark and rainy and it’s a 200 amp service which is good. I expect the 150 amp main breaker is just to protect it but again #notanelectrician.

Yes, we stubbed it up rather than capping and burying it and having to find it later. We thought about just having it stick up a few inches but then I would’ve tripped over it, kids would’ve hit it with dirt bikes/go karts etc hence the ridiculous height on it. I think cutting it back closer to the existing pad and heating up the sweeps and making them less angle and going to the side is probably the ticket. I just have to decide if I can do that before they start excavating for footings 🤔

 

[Herzog]

200 amp

You're solid for a 50A or 70A at the shop then, IMO but an actual electrician may say otherwise on the higher end. Awesome!

Edit - I'd pull wire for 100A just in case you upgrade your service at the house at some point. It will cost more but you can always do thicker gauge safely. Then just put a 50A breaker at both ends of the pull.

 

[shortstraw8]

Shortest straightest run you can get.
Short = less cost
Straight = easy to pull through
To pull just tie grocery bag on the end of some bull line and shop vac from the other end and use that bull line to pull the wire in. If needed any parts store has the metal Chinese fingers but staggering the main wire at the size for 100amp should be fine trought 2" for bends. I would have laid 3" schedule 40 but that's just me you get less heat to worry about and if needed later you can stub another small line in with no issue and you can reduce to 2" or whatever knockout you want to use on the panel to come up into + lube is messy and for the bedroom.

Where to place the panel in the shop, put it somewhere it won't be in the way
I would then put the panel on the trailer wall due to running wire for outlets will be easier and cheaper in the long run not having to go over the man door or into ceiling for multiple runs and you can potentially shorten welder run. Back wall is also good option just more money and I would avoid putting it in the center, find a hot box or weed burner and heat (carefully or it will collapse) the conduit to bend slightly to one corner way cheaper than sweep 90/45s.

Permit may dictate where the panel gets placed, usually not hard to get change approved though.
ufer ground will likely be required for code as it is a separate structure. At least it was in my experience even on small pump house sheds, allows the charge to disperses through the foundation. If there is no ufer I think it is only required on meter base outside of structure with grnd rods.

Has been since 09 ish since I last did any real thinking on wiring, uglys book is great for wire size calculations for derating over xmount of feet and conduit sizing as there is a heat to space requirement for conduit so the wire doesn't melt and catch fire but iirc you should be fine for 100amp service in 2"

 

[glockman]

I am running a 100 amp panel in my shop being fed from a 60 amp breaker in the house panel. Have ran welders and 220 compressor and haven't tripped the house breaker ever (15 years). I used the 100 amp panel to have more circuits and I used them all. I have 30 something outlets in a 25x40 shop. Outlets are cheap and very handy to have every 4 ft. I'd recommend putting the garage door opener outlet on it's own 15/20 amp circuit and using that outlet for an overhead cord real.

I'd have a ground put in the foundation (ufer) and also have them put a conduit in the foundation wall where you want your panel. Much cleaner than coming into the wall from outside or inside the foundation. I stubbed mine inside the foundation and now I have a conduit coming out of the floor and turning into the framed wall, which is ugly.
I have four 90s in the 3" conduit and I pulled THHN -2 wire through it. The run is only 35 ft but it was a bear. Rope through a pulley on a truss. My 200lb ass + gravity working as hard as I could to get it through with lube.

As far as the conduit going under concrete, I think we all over think this stuff. Would it suck to have to replace, yes. That said, how many mains have you seen needing to be replaced in say 20-30 year old homes? If the wire is sized correctly and you use the correct type of modern wire, it's more likely your house will be struck by lightning than have to replace that wire run.