Jwest

Shop Electrical Set Up

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Funny you should mention that Torch, but I've been doing just that. There is an interesting article on the in fine woodworking that I found through the New to Woodworking site: http://newtowoodworking.com/setting-up-shop/

In the setup shop section there is an article on a layout kit for small shops. While mine isn't necessarily small, I did find it interesting. He gives you cut outs with required space around that tool to use for layout. You can find the article there and look through it if you want. I liked it because I can easily play around with layout. Maybe when I find something I like, I'll post it on here and get some opinions. I'm going to use the layout diagram to get an idea what I want for outlets and location.

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==> I wouldnt mismatch the main panel and sub

+1

 

==> Local codes are different everywhere, some have them some don't.

+1  ... Our local guy allows white tape over black.  He also allows green tape over white.  Ground bars within 8' of main disconnect.  The point is, local trumps NEC every time -- you need his sticker to make the insurance folks happy.

 

The long and short of it is that it's cost effective to hire a local electrician to run the sub, bond the grounds, etc. and run your own local branches for the tools later... You may need to have one or two circuits run to make an inspector happy.  

 

I would go conduit and run a heaver gauge then you think you need now so that you don't have to pull cable later.  To save some $$, you can trench (but again check local code for depth) and lay the conduit.  Take photos with a yardstick indicating depth (in case the inspector wants to see it).  You also may want a second conduit for teleco/internet/tv/etc.  Have the electrician get the entire install inspected -- again maybe not much use now, may be useful later for the insurance folks.

 

When discussing with the electrician, I'd talk about a 100a panel with local disconnect -- in all honesty, a 100a panel is maybe $20 over a 60a panel...  The real $$ will be the wire.  The up-gauge will cost you probably $1.0+/ft more, but again years down the road you will be happy. 

 

As for actual power usage... I run a one-man shop, but have a shop helper on weekends.  I once attached a Fluke clamp-on amp meter to my sub legs to see what I was drawing:  lights, HVAC, DC, 5HP table saw and 6.5HP jointer all running, I was pulling about 50a.  Now, if I flip on the wide-belt sander, it spikes to about 100a, then settles to about 70a.  That's as much as I have ever drawn.  Note: shop air is piped in on a separate panel -- it would be about another 12a.  That's always been the basis for my recommendation of a 100a shop feed.  Now you certainly get by on less --- maybe even a lot less, but you still must account for startup inrush on motors -- for example a 3 HP motor may no-load at 12a, about 18a under load and almost 30a inrush.  I would not recommend going below a 60a sub feed.

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No you not correct about the blanket amperage draw of electrical motors. In my shop the 3hp cyclone will not run on a 20a wont even start the motor. The 3hp 12" jointer also will not run for more than a minute on a 20a. 5 Hp shaper will run all day long on a 20A. Its all about load not HP.

 

It is always best to look at the manufacturer's nameplate on the machine to figure the electrical load.  The sales department is often very generous with the HP rating printed on the front of the machine; the nameplate on the back will be much more realistic.  There are two critical numbers to look for: minimum circuit ampacity and maximum overcurrent protection device (OCPD).  The MCA is used to determine what size wire must be used to supply the machine and the max OCPD is the largest allowed breaker (or fuse) to protect the machine's circuit.  The other important number to look for is the full load amps (FLA) or service load amps (SLA).  This number tells you how many amps the machine will pull under heavy operating conditions.

 

I dont know if its nec or local but we are required to have a main disconnect at the sub panel in detached building with 6 throws but not attached. This both TPU and PSE inspectors.

 

NEC requires a main disconnect for a subpanel in a detached building if the subpanel has more than 6 throws.  A subpanel in the same building as the main does not require a main disconnect regardless of number of handles in the sub.

 

I wouldnt mismatch the main panel and sub. On the other hand dont see how you could trip a main breaker either. The individual tool breakers in the sub panel trip before the main.

 

The NEC does not require breaker coordination for residential services.  Without a detailed engineering study there's really no way to know which would trip first anyway even if the amp rating are matched or tiered.  The short-circuit trip component of the breaker trip mechanism is largely unpredictable.  Main breakers absolutely do trip -- mouse gets into the panel and shorts the buses, landscaper runs a ditch witch through the feeder cable, branch circuit breaker fails and melts to the bus bar, etc.

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If I had to dig the ditch I would look into renting a ditch witch . I mounted a lot of the boxes and conduit in my shop to save on labor costs.

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My shop is wired in a similar fashion to Steve's.. I have mounted boxes and emt tubing. This makes future changes easy, and Is not so labour intensive to install.

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Don't remember at this point who all posted what but if you pipe it all in EMT then skip the Romex and buy spooled strands. This will save a lot of space in the conduit.

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So, this was a long time coming, which is obvious by posting dates...but I finally got the shop electrical done. I save up and hired a contractor my company uses for all of it's electrical needs. He came out yesterday and installed a new 100 amp panel with plenty of slots, for a relatively fair price I thought. I used a lot of input from this blog in my decision making process so thanks for the advice. Also, I'm taking pictures of where everything is and laminating them for future reminders. I thought that was a great idea. I'm pretty pumped now. The elctrician said I really had less than 30 amps with the old set up. I guess it was tied into the panel my well pump is on. Now I have dedicated 100 amp service and he made it so I can connect my well to this panel if something ever happend to the line going to the well. Not sure if that made sense, but seemed like an added bonus.

 

Now i just have to figure out what new tools to get. Those outlets look so lonely.

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Hello All,

 

Haven't posted or checked the site in awhile due to moving and lack of internet. We recently purchased a great place on 6 acres with a 30 x 40 metal shop/barn. I was originally going to build a new shop since we have plenty of space, and use the old one for tractor and yard work type equipment. I recently have decided to just spend money to remodel and fix up the current shop and just build a small out building for the tractor. Sorry for the long intro, I tend to do that without realizing sometimes. Anyhow, I noticed that this shop has a subpanel with two breakers; a breaker for 1 outlet and a breaker for the lights. Yes...that's only one outlet...110.

 

So, that is what brings me to you all for counsel. I'm going to upgrade this shop in stages and first is electrical, since I can't really do much at all in there at this point. My question is, based on everyone's experience here how should I set this up? I'm guessing I'll need to have something like a 60amp breaker on the main panel to feed my shop. I'm going to have to bury a new power line for this, but no biggie. I don't have any 220 tools yet, but I would like to get them in the future.

 

What size sub panel would you all recommend?

How many 220 lines and 110 lines do you all typically run in your shop?

I'm guessing I should prep for all the major tools to be 220 right? (ie tablesaw, jointer, planer, DC, drum sander, etc??) All I have is 110 stuff right now.

 

I'm kinda unsure of what questions to even ask for electrical needs. I just want to do it right the first time, even if it's costly. Hope someone can give me some direction here. Thanks everyone. Sorry for the long post

General principles: Install a larger electrical panel than you ever see yourself needing because you will eventually use most of the breakers.  Having 220v gives you a lot of energy efficient options with many tools. Personally, all of my tools that will run on 220V, I put them on it.  You will never have too many receptacles.  Pick one 220v plug configuration and make everything standardized.

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Ok, maybe this is a totally dumb question, but I'll ask anyway. Could you expand on what you mean by "Pick one 220v plug configuration and make everything standardized."?

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240v plugs come in different configurations based on amperage draw just like 20 amp 120v home plugs have a sideways slot that allows for certain plugs that are made this way (to keep you from plugging it into a 15 amp circuit.) I would caution against this line of thinking. I would energize legs only as needed and buy receptacles that match the tooling. This means I would leave some runs coiled outside the panel until I had a tool planned for that location. Just me, might be overthinking things.

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