Electrical Limitations with Dust Collection

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Forum topic by Chris posted 12-01-2015 02:42 PM 1818 views 0 times favorited 15 replies Add to Favorites Watch
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177 posts in 1552 days

12-01-2015 02:42 PM

I am a complete rookie when it comes to electrical. I have a detached shop that has 2 – 15 amp breakers, one for lights, and one for electrical outlets spread throughout the shop. Dust collection has been an issue for me and I would like to change that. I would have pulled the trigger an a HF dust collector awhile ago but I read that it runs on 10+ amps, so I thought it would just trip the breaker every time I tried to use a tool.

HD has a deal on 16 gallon, 5 HP, Ridgid Shop Vacs that for $40 right now. I was about to get one of these and just roll it around from tool to tool as a work. I know they have the dust separators but I thought if its 16 gallons I could probably just pull the trigger on this one and save having to spend $100 more on a separator. When I looked at the specs online it stated the Ridgid Shop Vac runs on 10 amps too. Would I just trip a breaker every time I try to run a tool with the shop vac going? Here is a list of my bigger tools:

Old School Craftsman Table Saw with aftermarket Dayton 2HP motor
14 inch Delta Bandsaw
12 inch DeWalt Miter
I also have a 12 inch Drill Press and a Ridgid Sander

Any advice would be helpful. Thanks in advance.

15 replies so far

View Richard H's profile

Richard H

489 posts in 1648 days

#1 posted 12-01-2015 02:53 PM

It’s hard to say really. I have a 15amp circuit breaker to the wall outlets in my garage shop but it’s shared with the lights both in the shop and the kitchen so is very easy to trip at times. I swapped out all the lights in the kitchen with LED’s which did help but it’s still a lot on one circuit. I can use my shop vac plus small power tools like sanders together on it but when I tired to run my 1.5HP dust collector plus a power hungry tool like my planer at the same time on it I tripped the breaker. I also have a overhead 20amp breaker that goes to the garage down opener only that I use with a pull down extension reel for just about all my tools. I can run that with a dust fan or shop heater at the same time so I am confident that a single 20amp circuit breaker can handle a small dust collector/shop vac plus most smaller woodworking tools like the ones you mention at the same time.

Do you know what gauge the wire is in the shop? If it’s 10 or 12 gauge wire you might be able to (depending on length between breaker and shop) upgrade the breaker to 20amps. It’s not hard work but there are a few things to look for so it might be worth getting a electrical to at least quote the job so you get a idea of cost and if it’s even possible.

View conifur's profile


955 posts in 1119 days

#2 posted 12-01-2015 03:07 PM

It not just about tripping the breaker, my old garage had 15amp service if I would have the Sears Shop Vac on and start my contractor style TS it started slow, no tripped breaker but you can only get so much juice in a wire, just like water in a pipe, only so much room to push the water.

-- Knowledge and experience equals Wisdom, Michael Frankowski

View Chris 's profile


177 posts in 1552 days

#3 posted 12-01-2015 03:42 PM

Thanks to both of you for the reply. I will contact an electrician and if its too much $. This is what I needed to know.

View TheGreatJon's profile


337 posts in 1201 days

#4 posted 12-01-2015 04:20 PM

I have a detached shop that has 2 – 15 amp breakers, one for lights, and one for electrical outlets spread throughout the shop.

So the shop has a panel in it? I’m betting you have more juice available to you than 30amps.

I have a typical 200amp residential service, and I also have a detached shop. My main panel (in the house) has an 80 amp breaker that runs all of the power out to the shop. The sub-panel (in the shop) is rated up to 200amps, but I’m limited by the 80A breaker that is feeding it from the house. So I have 80 amps available to me at any given time in the shop.

Since I started collecting machines for my shop, I have put a couple new breakers (new circuits) into the shop’s sub-panel. I put in a dedicated 220v circuit for my dust collector, and a dedicated 220v circuit for my phase converter. The original 2 circuits were 110v 15A, just like yours. One circuit powers the lights and a few outlets in the ceiling, and the other cuircuit powers the outlets on the wall. I’ve never had a problem plugging my 110v machines into the wall outlets because I only run 1 at a time. Though, I noticed that the lamp by my previous band saw would dim while the band saw was getting up to speed (newer bandsaw goes on the phase-converter circuit).

If you have a sub panel in your shop, look to see what it is rated for, and check if you have any slots available for new circuits. Then, check to see what size of breaker goes from the main panel out to your shop. Or, take pictures and we could probably help explain what you’re looking at.

-- This is not the signature line you are looking for.

View rwe2156's profile


2883 posts in 1448 days

#5 posted 12-01-2015 04:29 PM

You definitely need more electric capacity.

Easiest way to get that is run a subpanel out to the shop with some 240v capacity.

Easy job for an electrician. Ask if you can supply labor to cut costs.

-- Everything is a prototype thats why its one of a kind!!

View MrUnix's profile


6598 posts in 2167 days

#6 posted 12-01-2015 04:56 PM

Old School Craftsman Table Saw with aftermarket Dayton 2HP motor.

That right there is probably pushing your existing 15A circuit to it’s max, or more :)
(General rule of thumb is ~14A per HP at full load – fortunately, you rarely run at full load)


-- Brad in FL - In Dog I trust... everything else is questionable

View Chris 's profile


177 posts in 1552 days

#7 posted 01-05-2016 07:26 PM

This is an old thread that I am hoping we can just kickstart right up again. I have taken pictures of my shop and the electrical too and from it. I have an electrician coming out tomorrow to take a look. Ideally, I would like at least another breaker with 15 amps to it and a 220 volt breaker option. However, I would take just another breaker if it cost a lot less.

Am I correct in that I only have 30 amps to my shop? Is it cheap/easy to add another breaker and/or 220 volt option?

Thanks for all the help.

View XquietflyX's profile


339 posts in 928 days

#8 posted 01-05-2016 08:04 PM

I’m interested in this too as i only have limited power to my Garage and just purchased the HF DC.

-- You can tell a lot about your wife by her hands, for example if they are around your throat she's prolly pissed off at you...

View WhyMe's profile


1008 posts in 1529 days

#9 posted 01-05-2016 08:43 PM

Chris, you have 30A to the shop. The wiring to the shop and the panel in the shop is wired incorrectly for both 120V and 240V. The wire feeding the shop needs to be 4 conductors and also the neutral needs to be isolated from the ground. And the shop needs an electrode (ground rods) system, which I don’t see a ground wire for coming from the garage panel. Here’s the proper way to wire a sub-pannel….

View dhazelton's profile


2756 posts in 2264 days

#10 posted 01-05-2016 08:59 PM

30 amps is about all that feeder cable can handle, so don’t think you can add more breakers in that box. You really need another line buried out to the garage with some more capacity. 15 amp receptacles are fine for things like small sanders or a drill or a biscuit cutter. A chop saw should be on a 20 amp circuit. Your table saw should definitely be on a 20 amp circuit. Most people think they need a 220 circuit but unless you plan on heavy duty welding you really don’t need it. I think if you had two more 20 amp circuits, one for a table saw/chop saw/jointer/planer and a separate one for the dust collection you would be okay because you don’t use them all at once. Things like a box fan and a radio and task lighting can run fine off the 15 amp while you work and the overhead lighting is separate. If you ever want an air conditioner in a window have them run 3 twenty amp circuits. Your lucky your garage is close by and you can dig a trench by hand in a few hours.

View WhyMe's profile


1008 posts in 1529 days

#11 posted 01-05-2016 09:14 PM

Unless my eyes are deceiving me the Romex to the lights and outlets look like yellow jacketed which means it’s #12 or 20A wire. If that’s the case then you can up the 15A breaker to a 20A for the outlets. You can add more breakers but you are limited on the total load used at one time because of the 30A feeding breaker. The total amps of breakers installed can be more that the total amperage of the feeding breaker. Another thing is you are not to have more than 6 breakers without having a main disconnect in/at the garage.

View Chris 's profile


177 posts in 1552 days

#12 posted 01-05-2016 09:39 PM

Thanks for all the replies. I was wrong in my original post and I should have mentioned this already but … the breakers in my sub panel say 20 not 15. So I think they are both 20 amp breakers.

If so, than it sounds like the smartest thing to do is have another 20 amp line dug out and run to that sub panel so I can run a dust collector device on top of whatever tool I am running. Does anybody have any idea how much if to have this done, along with fixing my sub panel? I don’t mind paying a professional, I just don’t want to get taken advantage of.

View clin's profile


827 posts in 964 days

#13 posted 01-05-2016 10:19 PM

I don’t fully understand what you have. But if it makes any sense at all, see if you can have larger wire pulled from the main panel to the sub-panel and increase that total capacity above 30 A. Maybe there is some code limitation, but 30 A is not a lot to work with for a shop.

Running a large power tool like a table saw and dust collection is quite a bit. I would want separate circuits for each. Then add on lights and it might not work.

Still 30 A will likely work okay if you run your DC and large tools off 240 V.

Regardless given your two 20 A circuits, and one is for lights, leaving a single 20 A circuit, is not going to be enough to run something like a dust collector and table saw at the same time. Unless both are on the small side.

Point is get your money’s worth out of any electrical work. Less expensive to get several things done at one time than to get the bare minimum done now, just to have the electrician back in a year when you realize the HF dust collector is too small or you want to run a 3 HP 240 V table saw etc.

-- Clin

View WhyMe's profile


1008 posts in 1529 days

#14 posted 01-06-2016 01:04 AM

You can’t add an additional 20A line to the shop, that’s a NEC violation. You can only have one feeder to the shop so the existing 30A needs to be abandoned/removed and a new feeder installed. Just add an additional 20A circuit breaker to your panel and see how it goes. The worst to happen is the 30A breaker will trip if a saw and DC are too much at the same time.

You really need to get that panel in order. If the feed is in conduit you need to pull a neutral from the main panel to the sub and add a ground bar to the sub and isolate the neutral bar and add ground rods. Actually the white wire should be the neutral and you need to pull an additional black.

Also 2 neutrals under one screw on the neutral bar is a no no.

View dhazelton's profile


2756 posts in 2264 days

#15 posted 01-06-2016 01:17 AM

Yes, best case scenario and the most expensive is to abandon all that ’s there already and run a new service to the garage. Cheapest solution is to get the fattest extension cord that will reach the house and use that for the other 20 amp circuit when you need it.

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