# Sub Panel for the Shop - 100 amps?



## maxman10 (Jan 4, 2011)

I'm putting in a sub panel and want to get input on what size I need. I cannot imagine exceeding the 100 amps at any one time. My dust collector is 20, but table saw is 20, various lights in electronics won't be much.


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## ryan50hrl (Jun 30, 2012)

I ran 60 and haven't came close to exceeding it as the most I can run at any one time is one tool, dust collection, lights and air filtration. Can you convert your saw and or dust collector to 220v? Cuts your amperage needs in half and makes wiring much cheaper


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## Fred Hargis (Apr 28, 2012)

I had 100 amps in my last one and now this one. The extra cost of 100 over a smaller panel is minimal, and you'll be covered if you add, say, a welder (ya' never know!). Plus the panel will have more slots, and I filled every one of them in both shops.


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## Steve Neul (Sep 2, 2011)

Put as big of a service in your shop as you can afford. It's best to plan for more and perhaps bigger equipment later.


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## ctwiggs1 (Mar 30, 2011)

My dust collector is close to bottom of the line and it pulls about 20A. My lights are fluorescent and combined pull about another 20. I'd prefer to have more than 20A remaining. Sounds like your TS alone would consume that. Now you are on the edge and from what I've learned, 60A available doesn't always mean 60A is available. What if you are working on a project while your wife or friend is working on another? What if you want to add a mini fridge or TV?

I'd definitely say grab a 100A panel. If nothing else, it'll be a nice factor for resale


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## mengtian (Nov 8, 2012)

100 amp. As noted earlier..cost is not that much of a difference and much better than getting cut short.


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## Itchytoe (Dec 17, 2011)

I believe 100 amps will be sufficient, unless you can feed 200 amps for about the same cost. Might only be another 25 bucks for the bigger breaker panel. I don't know what kind of set up you have or if you already have wiring ran or if you've got to run 150 feet of wire to feed your shop, so it's hard to know what extra cost it will be.

True, 200 amps is very likely more than you'll ever need in a one man shop, but maybe you'll add a small heat pump for climate control later, or a couple of window units, or just a few electric heaters for the winter. Like a cold beer? Maybe you'll find that the shop is the ideal place for a deep freezer too since it's out of the house, but close enough. Climate control, mini-fridge, deep freezer, dust collection, air filtration, and a table saw can eat up some amperage. Probably not 200 amps, but I'd rather have 200 available and only need 65, than have 60 available and need 65. I'd put at least 100 if I were you.


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## woodnthings (Jan 24, 2009)

*It's the number of slots also*



maxman10 said:


> I'm putting in a sub panel and want to get input on what size I need. I cannot imagine exceeding the 100 amps at any one time. My dust collector is 20, but table saw is 20, various lights in electronics won't be much.



Oh Great, another electric thread!  All caveats apply for this advice, which is only general in nature, not specific as to wire sizes etc. So, based on personal experience......

You will want as many slots in your new 100 AMP panel as possible.:yes: I have 5, yes 5, Square D - CO panels with 32 slots. This allows for up to 16 double pole (220 V) breakers which require 2 slots per breaker. My other 2 panels are 225 AMPS and 175 AMPs. The electric company loves me.... :laughing:

Your dust collector needs 20 AMPs from one leg of the 220 supply and requires only one single pole breaker.

Unless you have more than one person operating more than one machine each, you will never need the full 100 AMPs. However the sum total of the breakers can easily exceed 100 AMPs as long as the sub panel main breaker is rated at 100 AMPs. Make certain it has a main breaker so you can shut down the entire shop with one trip of the breaker.


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## Oneal-Woodworking (Apr 14, 2013)

Steve Neul said:


> Put as big of a service in your shop as you can afford. It's best to plan for more and perhaps bigger equipment later.


 
THIS for the win... :thumbsup:


Also pays to NOT run 'lampcord' for wiring... At some point when you get a BIG tool the 'lampcord' wiring will not be big enough for the job...


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## jhardesty82 (Apr 9, 2013)

As an Electrician by trade, A 100 amp panel should be plenty. You can get one with 20 or 30 slots. If your shop is 1,000 square feet or more I would recommend a panel with 30 slots, otherwise 20 would be fine. The size of your subpanel would also depend on the size of your main panel. You can't really have a subpanel the same size or bigger than the main panel that is feeding it.


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## CGull (Jun 14, 2013)

jhardesty82 said:


> As an Electrician by trade, A 100 amp panel should be plenty. You can get one with 20 or 30 slots. If your shop is 1,000 square feet or more I would recommend a panel with 30 slots, otherwise 20 would be fine. The size of your subpanel would also depend on the size of your main panel. You can't really have a subpanel the same size or bigger than the main panel that is feeding it.



Thanks for the info. My shop is about 800 sq. ft. Current panel has 12 slots I believe and a 12 slot sub panel should be plenty for my needs I would imagine.


http://www.acetoolonline.com/JET-JJ-6CSX-6-Closed-Stand-Jointer-Tilting-Fence-p/jet-708457k.htm

Can you answer this question for me? Take this tool for example, it can run on 110 or 230V. It will draw 6.5A @ 230V is there any reason I cannot wire the machine for 230V and attach a 20A plug on the end of it to plug into a 240v 20A outlet?


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## ryan50hrl (Jun 30, 2012)

Yes, 20 amps requires 12 gauge wiring, and likely that tool has a 14 gauge cord. Now there's nothing wrong with putting a 15 amp plug on it and plugging it into a 20 amp circuit.


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## jhardesty82 (Apr 9, 2013)

Nope, no problem at all. A lot of electrical equipment will have different voltages listed on them, such as one item would say 110 volts and another item would say 120 volts. They really are rated the same. The same goes for 230 and 240.


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## jhardesty82 (Apr 9, 2013)

The gauge of the wire on the power cord of the tool it self doesn't really matter since the tool isn't going to draw more than the 13 amps it is rated at for 110 volts anyways. The rating of the plug and receptacle are just what they can withstand, it doesn't mean that is how much amperage is there. A 15 amp 240 volt plug would also work but if you already have a 20 amp plug, it is fine.


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## CGull (Jun 14, 2013)

jhardesty82 said:


> The gauge of the wire on the power cord of the tool it self doesn't really matter since the tool isn't going to draw more than the 13 amps it is rated at for 110 volts anyways. The rating of the plug and receptacle are just what they can withstand, it doesn't mean that is how much amperage is there. A 15 amp 240 volt plug would also work but if you already have a 20 amp plug, it is fine.


Thanks, electrical stuff has always confused me.


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## Itchytoe (Dec 17, 2011)

CGull said:


> Can you answer this question for me? Take this tool for example, it can run on 110 or 230V. It will draw 6.5A @ 230V is there any reason I cannot wire the machine for 230V and attach a 20A plug on the end of it to plug into a 240v 20A outlet?


Nope, no reason why you can't do that. If it's the 10 volt difference that worries you, stop worrying. 110, 115, 120, 220, 230, and 240 volt designations are nominal values. What that really means is that you can run the equipment off one hot leg and a ground, or two hot legs that ground each other. (Yes your voltages have to be somewhat close to 115 or 230, but give or take 15 volts and you'll be fine.) I have 124 volts, or 248 volts available in my home. You may have as little as 108 and 215 volts, but it's all the same service, despite the different actual voltages. Get a volt meter and check your voltage. I bet it's not 120 volts. It'll be close, but probably not exactly 120. Ironically, if you actually have 110 volt legs, you won't have 230 volts, you'd have 220 volts.


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## rrbrown (Feb 15, 2009)

ctwiggs1 said:


> My dust collector is close to bottom of the line and it pulls about 20A. My lights are fluorescent and combined pull about another 20. I'd prefer to have more than 20A remaining. Sounds like your TS alone would consume that. Now you are on the edge and from what I've learned, 60A available doesn't always mean 60A is available. What if you are working on a project while your wife or friend is working on another? What if you want to add a mini fridge or TV?
> 
> I'd definitely say grab a 100A panel. If nothing else, it'll be a nice factor for resale


Are you serious. Your dust collector if its a 2 HP motor may draw lose to 20 amps, the table saw again I doubt it draws 20 amps. Both those things may draw close to 20 amps on start up only. 20 amps worth of fluorescent lighting? How many light are we talking. Really a mini fridge and TV are negligible in amperage draw.

I have 60 amps service. 60 amps is 60 on each of two legs so if your talking 110 volts you actually have 120 amps. I have a 10k and 12k but window units, 20 compact fluorescent bulbs and (20) 4' T-8 fluorescent bulbs, 4 floodlights, a stereo and or Tv, a mini fridge, dust collector, 4 HP ompressor (220v) and any number of power tools from a 3 HP 220 table saw down that can run at one time and the lights don't even dim. 

My only problem to date is the drum sander overloading when I tried to take off to much at a time. Not a single other problem. 

Now with that said, I don't disagree if your running the power run the 100 amp if you can. I disagree with our assumption of power consumption and view of how little can be ran on a 60 amp service panel.


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## ryan50hrl (Jun 30, 2012)

The size of the cord absolutely does matter. The sizing guides exist for a reason. What if some day that cord is removed, and someone reuses it? Just because it will work doesn't mean it should be done. Buy a 15 amp plug( which will work in a 20 amp outlet, and be done with it.


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## ryan50hrl (Jun 30, 2012)

rrbrown said:


> Are you serious. Your dust collector if its a 2 HP motor may draw lose to 20 amps, the table saw again I doubt it draws 20 amps. Both those things may draw close to 20 amps on start up only. 20 amps worth of fluorescent lighting? How many light are we talking. Really a mini fridge and TV are negligible in amperage draw.
> 
> I have 60 amps service. 60 amps is 60 on each of two legs so if your talking 110 volts you actually have 120 amps. I have a 10k and 12k but window units, 20 compact fluorescent bulbs and (20) 4' T-8 fluorescent bulbs, 4 floodlights, a stereo and or Tv, a mini fridge, dust collector, 4 HP ompressor (220v) and any number of power tools from a 3 HP 220 table saw down that can run at one time and the lights don't even dim.
> 
> ...


 Agreed, I've run an amp meter on my panel, and the max I've ever been able to cause it to draw not during start up is 32 amps. That was the dust collector with all gates open, the air filter, every light, the router running with no load and the tablesaw bogging down in 2 inch hard maple.


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## rrbrown (Feb 15, 2009)

woodnthings said:


> Oh Great, another electric thread!  All caveats apply for this advice, which is only general in nature, not specific as to wire sizes etc. So, based on personal experience......
> 
> You will want as many slots in your new 100 AMP panel as possible.:yes: I have 5, yes 5, Square D - CO panels with 32 slots. This allows for up to 16 double pole (220 V) breakers which require 2 slots per breaker. My other 2 panels are 225 AMPS and 175 AMPs. The electric company loves me.... :laughing:
> 
> ...


Bill all those service panels and I probably still pay more for power then you. Freaking heat and humidity here sucks.:laughing:


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## jhardesty82 (Apr 9, 2013)

ryan50hrl said:


> The size of the cord absolutely does matter. The sizing guides exist for a reason. What if some day that cord is removed, and someone reuses it? Just because it will work doesn't mean it should be done. Buy a 15 amp plug( which will work in a 20 amp outlet, and be done with it.


I guess I don't understand why someone would reuse a power cord off of a tool that is probably only 6 feet long. Now if your making your own power cord so that it is longer, agreed use 12 gauge wire or use a 15 amp plug if said cord is only 14 gauge.


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## ryan50hrl (Jun 30, 2012)

I don't either, but my point is why risk it? What's the harm in buying the right plug? The whole premise of electrical codes is risk adverse planning, 14 gauge wiring in much of the rest of the world will carry 20 amps, but to be on the safe side we rate it to 15. Same things with plugs, will it work, sure, but it's still not right.


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