This is the first time post for me here. I am in the process of reclaiming my garage from the cars and putting my shop back in action. The house electrical panel is in the garage with easy access. I need to add circuits to handle (immediately) two pieces of equipment. A dust collector at 12A & a new band saw that is on the way. It will require 10A. Would it be ok to combine those into one 30A two pole breaker with the outlets in series, or am I pushing it? I will be adding a Unisaw next and that will be 220 as well. I don’t want to fill up my existing slots if possible. I want to add a couple of 20A 110’s for smaller tools. Since both the dust collector and saw will be running at the same time, will I be taking chances? In theory I should have 8 amps to spare, correct? If I run them together I would use 10awg wiring and properly rated plugs. Any suggestions? should these be split into two?
Discussion Forum
Discussion Forum
Up Next
Video Shorts
Featured Story
Learn more about the benefits and compliance details for the DOE's new water heater energy-efficiency standards.
Featured Video
SawStop's Portable Tablesaw is Bigger and Better Than BeforeHighlights
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Replies
Think about the max number you will need. In my garage I have three 120 for bench and portable equipment, a 120 for lights, a 120 for dust collector and air filter, and a 220 for the cabinet saw. I still have 4 full size slots for 2 additional 220, likely a planer and a mig welder, in the future.
If you are already short on slots, then an 8/16 or 12/24 subpanel might be called for.
The problem with your plan is that the equipment comes with plugs for standard 120 outlets, and on a 30A circuit everything has to be rated for the maximum load, breaker, wire, and receptacles.
Thanks for the feedback. The DC has a 220 plug with appropriate wiring. The new Grizzly 17" BS comes without a plug. It's up to you to terminate it. I have enough slots to split them but would be close to maxing it out. If I run them separately I can run 12/2. If they are together I will need a 10awg wire to handle the xtra amps. I would hate to end up having to do a rewire or run more conduit. Just trying to be efficient.
Most likely DC comes with a 20 amp plug (6-20), but you can't install 20 amp receptacles on a 30 amp circuit.
(http://www.networkcable.com/pages/components/nema_nonlocking.html)
I would recommend that you have a separate circuit for the DC, but you can run a common 240 circuit for the BS, TS etc.
Read the original post twice, and maybe I am still missing something.
Dust collector is 12 amp/ 220 volt. Band saw is 10 amp/ 120 volt. Future table saw will most likey be 220v/15-20 amp cabinet type saw.
Looking at that, wouldn't going to mini breakers for the 120v circuits make more sense? Replace two standard 120v breakes and you get four 120 circuits in the same space ( two existing and two new).
The 220v circuits should be run as dedicated circuits to the respective equipment, IMO, not combine with one leg being use for 120v equipment.
Dave
Sorry for the confusion. All are 220. If I were to combine and use 10awg, I would use the appropriate plug i.e. 30a rated plug. I would just run the two in series to the same two pole 30a breaker. If I seperate into two seperate circuits, I will use 12awg wire to seperate 20A breakers. When I get the new table saw, due to it's probable rating of 20+ amps, It will require an aditional circuit. I'm feeling uneasy about combining the two, but if it's not required, why waste valuable box space? Hope that clears up my question
Do yourself a favor and install the subpanel.
Do yourself a favor and install the subpanel
Yup. Small subpanels and breakers are cheap; do it the right way. Any motor big enough to run off of 220V deserves its own branch circuit.
The results are pouring in. Here is one response:
"If the motor for the band saw has a overload built into the motor that would protect the motor and the wire feeding it from over load and the same with the dust collector then the 30 amp breaker, receptacle and plug would only have to be protected for fault current wouldn't it? 430.52. I still think it would be a UL listing issue to cut off a manufacture installed cord end and install a different plug but I don't think the NEC address's this or does it?"I think the general idea is that you would be exposing a machine designed for 20 amps to 30 amps. Do you have a permit? Let us know what the inspector thinks of this arrangement.
~Peter
"I still think it would be a UL listing issue to cut off a manufacture installed cord end and install a different plug"
Most of this stuff is not UL listed. You have to look on the machinery label to tell for sure.
Now the MOTOR might be listed, and the CORD or CORDSET migh be listed.
But the woodworking machinery is most likely not listed.
> you would be exposing a machine designed for 20 amps to 30 amps.
The machine pulls as much as it wants, the breaker doesn't push extra amps into it. You can put a 15 watt lightbulb on a 30 amp circuit, and it'll pull exactly the same current it would on any other circuit.
The breaker isn't supposed to provide overload protection to things that are plugged into its circuit. Its job is to provide overload protection to the wires that are built into the building. If an application needs overload protection, it should be designed and built into it by the manufacturer.
-- J.S.
Thanks for all the feedback. I had an electrician come by and code says we can run them in series. He said as long as we don't exceed the rating and have some to spare. He said not to go over 24a on a 30a breaker. I decided to let him do it because the project grew and now I'm addind 2 110's and good lighting all around. He is going to run an aditional conduit to accomodate the purchase of the TS next year. I'll run the wire and connect into the box after the amps are determined.
Yes, you're fine with 8 amps to spare. And the saw doesn't pull its full rated load all the time, only when it's actually doing some very heavy cutting. With the blade just spinning between cuts, it pulls very little.
-- J.S.
Thanks.
It was already mentioned that you cannot use any 20 amp receptacle on a 30 amp circuit. The question is whether it is permissible to change the plug on your 20 amp device to a 30 amp 220 plug.
Usually 30 amp and up receptacles are intended for a specific appliance in a particular location. E.G. air conditioner. A welding machine may have several receptacles dedicate for it in different locations so it can be moved around but it would be plugged into only one receptacle at a time.
This is an interesting question and will have to be exposed to a higher authority.
~Peter
You are not protecting you electrical loads if you combine loads then go oversize on the breaker.
In this case I would also recommend a subpanel and proper breaker size for each dedicated load.
Lastly are you sure you want to be in series?
Bake
Edited 5/19/2004 11:49 pm ET by bake