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Forum topic by HorizontalMike posted 06-04-2010 04:55 AM 3006 views 0 times favorited 19 replies Add to Favorites Watch
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HorizontalMike

7160 posts in 2382 days


06-04-2010 04:55 AM

I am in the process of setting up my workshop for the first time and am re-arranging and changing breakers in my 125amp feed box in the garage. This box is controlled by a 100amp breaker on the house’s 200amp main feed. My question(s) are regarding how big my 220v breakers should be for:

14” Rikon 10-325 BS wired for 220v – States 7amp@220v (thinking 220v 20amp breaker?)
Grizzly 1023RLW TS – States min. of 220v 30amp service (should it be any bigger than this?)
Harbor Freight generic 2hp 110v Dust Collector States 20amp (dedicated 110v 20amp breaker?)

*I am running 10-2 Armor-clad for all 200v outlets from the garage feed box. I am also planning on replacing the 6ft long 14-3 cord on the 14” Rikon BS with 10-12ft of 12-3 AWG for 220v service. Both my BS and TS will be on mobile bases in order to conserve space. Haven’t thought about the planer setup yet but expect it to also be mobile. Any ideas?

Am I on track here, or have I missed something?

-- HorizontalMike -- "Woodpeckers understand..."


19 replies so far

View TopamaxSurvivor's profile

TopamaxSurvivor

17677 posts in 3144 days


#1 posted 06-04-2010 07:32 AM

If that HF dust collector is really 2 hp, it needs #10 and maybe up to 50 amp breaker to start it. What is the Hp of the Grizz TS? Band saw should be OK.

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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WoodSparky

200 posts in 2570 days


#2 posted 06-04-2010 09:08 AM

I like to keep all my tools on mobile bases. You never know when you need to move them for that ” Special Cut”, or at least clean up under them.

The band saw probably only needs a 15amp circuit at 240v, but a 20amp would be fine.
The table saw’s 3hp motor would be fine on a 30amp circuit at 240v.
The DC 120v 2hp motor will run on a 20amp circuit. The full load of a 2hp motor is 24amps. I do not see it drawing that much, unless you get a jam. 50amps for this circuit is not needed, unless you also plan to Arc Weld.

-- So Many tools, So little time

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HorizontalMike

7160 posts in 2382 days


#3 posted 06-04-2010 02:57 PM

Thanks guys. The HF DC actually states 20amps “peak” and will be fed from a box just a foot below the main feed into the garage/shop, so a 20amp breaker sounds good to me since my box is well populated with them. Depending on how well this DC works I could always move it outside during use. It will be located directly between the walk-in door and the 8’x16’ overhead. Doors will be open nearly all the time most of the year. I am already seeing 95-104F in the garage daily. Drinking lots of H2O with circulating fans on high and enjoying every minute of it. If I keep this up I might actually be able to read the fence setting WITHOUT having to step backwards to get a clear view 8-).

-- HorizontalMike -- "Woodpeckers understand..."

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TopamaxSurvivor

17677 posts in 3144 days


#4 posted 06-05-2010 01:45 AM

Code requires #10 for 2 hp on 120v and alows 50 amp breaker to get it started.

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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hairy

2384 posts in 3000 days


#5 posted 06-05-2010 02:06 AM

My tablesaw is rated 17 amps FLA. A local electric shop told me that means Fully Loaded Amperage. It is 220vac.
It blows a 20 amp breaker on startup. I’m using a 30 amp breaker on 12 – 3, it’s good to 20 amps.

I haven’t had a problem, but I know it’s not right. I found out later the guy I bought it from did the same for years without a problem, but it still ain’t right.

What I need to do is run a new circuit for the tablesaw. Right now that circuit is used by tablesaw and air compressor. Around here, and most likely everywhere in the USA, only 1 outlet can be on a 220 volt circuit.

I unplug the compressor to use the tablesaw.

-- stay thirsty my friends...

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BlankMan

1488 posts in 2821 days


#6 posted 06-05-2010 05:18 AM

It sound like you’re on track, even with the 20A for the dust collector that should be fine. If it were starting up against a load like an air compressor does once it has bled down a bit the motor class rating would come into play and then mostly likely the 20A wouldn’t cut it. But a DC doesn’t start up with a load the load develops with impeller RPM which then it will draw FLA when at speed. Ran into this with an air compressor and landed up putting it on a 20A time delay fuse protected by and wired for a 30A breaker. That way the fuse properly protects the motor but the breaker doesn’t pop on inrush.

But I’m curious, a 30A 220V circuit for the TS? What HP is that and what’s the motor rated Amps at 220V?

-- -Curt, Milwaukee, WI

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BlankMan

1488 posts in 2821 days


#7 posted 06-05-2010 05:21 AM

Topa, 10 on a 50A breaker? I would expect that it would have to be at least 8 then?

BTW I checked out 50A 120V plugs and outlets when I had the AC issue. Huge. Didn’t want to go that route, hence the 20A T fuse and the 30A breaker.

And I would think if you used a 50A 120A circuit you couldn’t then use the standard 15A/20A outlet and remain in code.

-- -Curt, Milwaukee, WI

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TopamaxSurvivor

17677 posts in 3144 days


#8 posted 06-05-2010 05:27 AM

Motor circuits are allowed to be fuesd higher to allow for the motor to start.

If that DC is running on a 20 amp 120 v circuit, it isn’t 2 hp. Has to be considerably less. Most motors draw close to full load amps with no load.

I noticed a 3 1/4 hp router on another thread that draws 14 amps. That is only a 1 hp load. Seems they are being a bit optimistic on HP these days :-))

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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HorizontalMike

7160 posts in 2382 days


#9 posted 06-05-2010 06:05 AM

Well, I managed to get the dang HF DC put together after HF shorted me on fasteners (18 8mm-1.25 nuts to be precise). When will manufacturers realize that skimpin’ on the hardware cost them a lot more than the cost of a few nuts/bolts. I called HF in Bangalore and the guy tried to give me a hard time. “Nuts” to him (pun intended). Anyway after trip to the Home Despot for metric nuts (specialty hardware in the USA) I got the thing setup and it starts easily on a 20amp 120v circuit. Granted it is running a clean/new filter bag but 20 seems fine for now. If it starts popping the breaker under load, I’ll bump it to a 30amp. I think I would prefer running reasonably “near” max breaker load than have the thing burn up before tripping something like the 50amp suggested.

Also finished rewiring the 10-325 BS for 240v with 14’ of 12-3AWG and installed a dedicated 20amp 240v breaker just for the BS. That short 6ft OEM cord would have been like stringing a cloths line considering that my outlets are 48” high on the wall.

I will install a separate 240v 30 amp for the TS when it arrives later this month. I want to be sure where/how the power cord runs from the machine before mounting the outlet to the wall in order to maximize how far I can roll it into the center of the shop when in use.

-- HorizontalMike -- "Woodpeckers understand..."

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TopamaxSurvivor

17677 posts in 3144 days


#10 posted 06-05-2010 06:28 AM

If it starts and runs on 20, use it.

The circuit breaker is not to keep your motor from burning up. It is for over current and short circuit protection. Motor over load protection is provided in motors whose name plate say it is “Thermally protected”. They may have a reset button or it may be automatic. If the name plate does not say that, then you need a motor overload switch or magnetic starter to do the job.

Most circuit breakers operate on thermal overload only. They will carry more current longer than thermal/magnetic breakers which trip almost instantaneously on overload. A 20 or 30 amp thermally operated breaker will usually start a motor that would require a 40 or 50 amp thermal/magnetic breaker. Sort of like needing a 50 standard fuse or a 30 amp dual element time delay fuse to start the same motor. I hope I have simplified that enough to make sense.

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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fussy

980 posts in 2518 days


#11 posted 06-05-2010 06:37 AM

Mike,
It would seem to me that you’re over-building your wiring in a big way. Not that that is bad, but more expensive than necessary. For example, the HF dc is rated 20 amp “peak” which is essentially meaningless. It pulls 11 amps running steadily, and I’ve never seen it go over that except a split-second at start-up when it hit 16 amps. I have mine on a dedicated 20 amp circuit only because it was available. You might consider that separate circuits for the ts, bs, planer, jointer, etc are unnecessary if you size it for the largest load as you can use only ONE tool at a time.

As far as running at or near breaker rating to protect the tool, the breaker protects the wiring and thus your shop—not the tool. It is just possible to burn the motor on a properly sized breaker as on one too large.

Anyway, if in doubt, as an electrician. It’s cheaper by far than the deductible on your fire insurance.

Steve

-- Steve in KY. 44 years so far with my lovely bride. Think I'll keep her.

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MisterCat

22 posts in 2391 days


#12 posted 06-05-2010 06:46 AM

Mike, I have the same table saw you do, and have it running off a 30 amp (220 v) circuit. I’ve never popped the circuit breaker. I installed a single 220 v receptacle for the garage, and made up a heavy duty extension cord to go between wall and equipment. I did this because all my equipment has to be on mobile bases.

Topa is right on the dust collector and breaker sizing. NEC states motors can have breakers up to 250% of the amperage capacity of the wire to the motor. NEC table430.248 lists a 120v, 2 hp motor as drawing 24 amps. NEC table 310.16 (and the limitation footnote 240.4 (D) gives 20 amps for 12 gage copper wire and 30 amps for 10 gage. This means you should use 10 gage wire to your dust collector and you can use a circuit breaker of up to 60 amps. I’d choose 50 amps for this case.

For the tablesaw, NEC says a 3 HP 240v motor draws 17 amps. So you could use 12 gage copper wire and up to a 40 amp circuit breaker (not a common breaker size, so 30 is probably your choice here), with the 10 gage wire you plan to use, you could put a 50 amp circuit breaker in.

NOTES: amperage capacity given for copper wire. Copper clad aluminum wire drops the capacity by 5 amps. To qualify for the 250% circuit breaker allowance, the circuit breaker has to be directly wired to motors. In my case I can’t use anything more than a 30 amp breaker on my 220v receptacle, even though all Irun off of it is a table saw.

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TopamaxSurvivor

17677 posts in 3144 days


#13 posted 06-05-2010 07:16 AM

If that HF DC is drawing 11 amps, it is a 3/4 hp at most ;-)) not even close to 2 hp!

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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WoodSparky

200 posts in 2570 days


#14 posted 06-05-2010 12:59 PM

Mister Cat; do they still make or use Copper clad? I have never bought or used it. I had only encountered it once on a job here in NJ.

-- So Many tools, So little time

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HorizontalMike

7160 posts in 2382 days


#15 posted 06-05-2010 05:22 PM

Topa, thanks for the explanation. Used to work as a Navy electrician some 40yr. ago and have forgotten much but remember just enough to confuse myself more often than not ;-)

Fussy, as far as “over building” the wiring—I built the 24’x30’ garage ~6 years ago and installed separate 120v breakers for nearly each 120v 4-gang receptacle and lighting at that time. Guilty as charged, but this occurred several years ago 8-). Hey, it was the Man Room after all, ya know… 50ft from the spouse erh uh… house.

Only added costs for the feed this time around are; ~$8.50 for each of the 20amp(BS) and 30amp(TS) 240v breakers, ~$90 for 125’ coil of grounded 10-2 armorclad for 240v outlets and then ~$20×2 for each additional 240v outlet/plug combo added (2 so far). Had a couple of 4-gang boxes left over from original build and only needed to buy the L6 cover plates. May use the extra 10-2 armorclad for more 120v outlets as needed. Original outlets were spaced at 15’ on MetalMart building w/4-gang box on each vertical beam (no structural wall between beams, just sheet-metal exterior wall with a horizontal perlon @7ft. Over the years I found that I could actually use additional 120v boxes on at least two of the walls so part of this is add-on is long overdue.

MisterCat, I like the idea of adding mobile bases to everything, not so much that I don’t have the floor space but my other hobby, the scooter, has its own maintenance and parking area that takes up about 1/3 of the space. The original BS cord was 14-3 and was replaced w/12-3 of longer length to make the BS more usable/movable without an extension cord since my metal building layout makes adding circuits very easy. I do not know what gauge the TS (1023RLW) cord will come with but assuming 12-3. Feed to it will be grounded 10-2 so don’t see changing the TS cord (comes with 10ft length but without plug).

Need to get rid of some shipping boxes and then I’ll take a couple pictures to give you all an idea of my what my shop will look like. Just hate to get rid of them until I’m sure everything works.

-- HorizontalMike -- "Woodpeckers understand..."

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