So I got my 5 HP Unisaw and can’t plug it in.
First fun discovery: The Zinsco panel I have is a total mess (if you press on it, the house lights blink!), so I’ll have to install a new service panel to add my two new 240/30A and my two new 110/20A circuits.
Second fun discovery: GFI for 240v is VERY expensive. But, per my inspector, not required. So I won’t be running the TS, future BS, etc. on a GFI even though I’m in a garage.
Third fun discovery: You can’t effectively run 20A GFI 110’s in a three-wire circuit (two hots in a 12/3+g). Why? Well, the neutral for one hot will float around according to the load on the other hot, causing all sorts of false trips. So no saving $$ by running 12/3 for both circuits — you have to run two sets of 12/2.
So tomorrow the inspector will come out to do a “Q&A session”, check all the equipment I bought and how I plan to install; I’ll see two electricians on Fri. and Sat. for estimates on the help I need. A lot of unexpected hassle and expense, but once this is done, my electrical will be very stable for the shop, with two independent 240/30A circuits, plus two independent 120/20A circuits.
So I might have my power in a week or two. Then I can start putting the Unisaw to work. Yay!
Replies
GFCI on 240v machines are not needed (IMO) because the machine should be grounded, and is quasi-stationary, thereby not seeing the wear and tear of something like a drill-motor.
Zinsco=bad bad bad
"GFCI on 240v machines are not needed (IMO) because the machine should be grounded, ..."
Are you referring to a separate ground wire connected from the machine frame to some local grounding point in the shop? Or is this referring to the normal ground circuit wired through the 240 v line into the power outlet?
The normal ground wire. Plus, you're not likely to plug an old, frayed extension cord into it, run it outside across wet grass, and hook it up to an electric weed wacker.
Vulcan: As an electrician for several decades Zinsco was always a joke, maybe in their time they were good but it always seemed when I or anyone I knew came across Zinsco panels they were problematic. On the GFI issue it seems like people overdo putting them everywhere. They are life-savers in the right circumstances but don't do much in a dry shop with everything properly grounded. They require checking for continued effectiveness. I have replaced about five in my career that failed ''on'', in other words the protection was gone but the power was still on, the opposite of ''fail safe''.
What brand/model of panel did you buy? Last time I looked there weren't any ''bad'' brands but now a days with all the cheap knock-offs I'm not sure. I was always spoiled working on mostly industrial stuff, when I look at a residential receptacle it looks like a toy. Do your self a favor and buy spec type receptacles especially in places where things will be plugged in and out frequently. You can also use 20 amp types on 15 or 20 amp circuits, they have heavier contacts and will last longer.
Good Luck and happy wireing, Duke
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Edited 10/5/2005 9:22 pm ET by dukeone
I bought Square D QO, a 200A 30/40. No tandem breakers, and there'll be 5 spaces left once I've done all my work.
I decided not to GFI the 240 because code allows me not to; I honestly presumed it was as you described -- safe, or the code would be otherwise.
I'm taking your advice on the 110's left-handedly, by installing all 20A fixtures (and 12/2 wire and a 20A breaker). Now those ARE GFI'd, by means of an outlet GFI adjacent to the panel. I bought heavy-duty 20A's for the location I expect to use most, as well.
I'll heed your caution and test the GFI's regularly, as elsewhere recommended. Good thing is, they're only $12 to replace when necessary (much cheaper than replacing a GFI breaker).
I'll tell you, the hardest part for me is getting all that wire packed into an outlet box. For example, the 240 box containing the 6-30R has two 10/2 (+ground) Romex (incoming and outgoing), with both hots and the ground pigtailed up to the outlet. So that's three wire nuts, all that wire, and the socket in a box. Any hints on folding that stuff in nicely? :)
....not enough room for the wires ?
I count 10 wires and a 4" sq X 2 1/8 metal box or better yet ,
a 4 11/16 sq. X 1 1/2 and a raised cover for either one, but that eliminates the box for future use as a J-boxmy preference is the 411/16 X 2 1/8 , .....the deeper the better"....oops forgot to count the cable clamps......make that 11 wires
Edited 10/6/2005 8:54 am ET by maddog3
Vulcan: Sounds like you have it well under control. Square D QO is one of the most used panels in my experience. Not using tandems for motor loads and having spare spaces are good ideas. As far as fitting all that stuff into a box:
Use a larger box, if space is not a problem use a 4 11/16 box for anything larger then single 20 amp outlet or switch.
Use an uninsulated ''barrel'' connector for the ground, it saves a bit of space.
Leave about 6'' of wire on the pigtail, fold the splices into the back of the box first, two at the top and one at the bottom of the box.
If flush mounting in sheetrock etc. mount box further back and use a deeper ring.
Arrange installation for no splices in outlet box ie: have junction boxes separately above and a drop to the outlet. This also simplifies trouble shooting should a splice get loose.
Code also specifies how many wires, devices etc. in a size of box cover combination because overcrowding is unsafe. To be on the safe side extra room is always welcome in my opinion, for safety, code compliance and ease of installation. On another related issue have you seen the wirenuts that can be tightened with a nut driver? I believe Ideal is the brand, it saves fingers if doing many splices and insures a tight connection.
Duke
Kenneth Duke Masters
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My hardest install is a 6-30R in a single box. These are flush-mount nail-on boxes, plastic so no ground to the box (just to the outlet).
My hardest problem is the "folding" you describe. I'm wondering if bent-nose pliers might make the bending easier? My fingers are neither terribly long nor strong, and that 10 wire is hard to bend easily. Advice here would be VERY welcome.
Regarding two at top and one at bottom, I presume it's good to put the ground at bottom, since it's uninsulated?
I wasn't quite understanding the # wires rules, so last night I wired up a 110 and a 220 the way I'm planning to do it; I'll show it to the code guy today and change boxes etc. if he so recommends.
Thanks for the j-box hint. It just sounds like a bit more hassle, because they have to remain accessible so that's a lot of j-boxes visible in the shop. Already, each "power location" (there are 4) has three boxes (one for each 240, one for both 110's) I have to install...
Vulcan: I'd be very careful using any metal tool to pre-form the conductors. If you need to maybe a piece of dowel to bend the wire around. If you keep all the wires away from the terminals as best as you can, other then the connected ones, it won't mater which is where. Some receptacles don't fit in a handy box at all so if your 6-30R is very tight it might demand a larger box. Info on that might be on the box it came in ie: minimum box size for 6-30R. What size boxes are we talking about here and what kind of cable are you using? DukeKenneth Duke Masters
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Hey the inspector just left... my 240v is going to take some redesign, because I can't run multiple 240v sockets on a single circuit. Bummer. Anyways it means I won't be packing so much wire in... much easier, thanks!
You know the inspector rules but I don't think that multiple outlets on 240 is not code. Can't quite remember, don't have code book anymore and have been away from it for over five years. Since at home you won't be running more then one machine at a time, other then the d/c, why would it mater? I also worked mostly on industrial stuff and haven't dealt with residential wiring much. When I rewired my rentals basement the inspector didn't seem to understand much, I'd bet I could have done all kinds of improper wiring, she barely looked although I did forget a cover on a j-box. DukeKenneth Duke Masters
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I also worked mostly on industrial stuff .. Hell, we installed buss bars where 240 fed a box with a drop down cable and Twist Lock Plug about every 4 feet!But the same here.. Just one 230 allowed? Stupid Village inspector..
I went to the Village Fire Department and they had them all over the walls! IT DID NOT HELP MY CASE! GeeeeeI Made up a box with a twist lock receptacle and #12 Cable.. Two Hots Neutral ( Capped OFF and not used ) and a Ground I could plug all my 230 stuff into.. It passed??? Geee again.. I never told the inspector her was a JERK and I have a degree in Electrical engineering.. Besides it would not matter.. What Inspector say GOES! At least here!
Truth is, it's not that big a thing to go ahead and run the extra circuits per his advice, so that's what I'll do. The extra 30A breakers just don't cost that much, and maybe the next owner of the house will be glad to have the independent power points.
Yesterday my sons and I got the two new ground rods pounded in. Man that's hard work.
Also got a good estimate for the electrician, so I'll have help putting in the new panel. Soon as I get the last of the cleanup in the
garageshop done, I'll start removing drywall, drilling stud/joist holes and installing conduit... then it's run cable, install boxes, and then on to the panel!Thanks to everyone for the excellent help!
I hope that inspector doesn't come around my place! I have 'multiple' 240 outlets on the same circuit just because of what you say -"Only one machine plugged in at a time."
Jerry
Jerry: From a purely safety view if you tried to run two 20 amp machines on one 20 amp circuit with multiple outlets the breaker would trip, no different then trying to run the toaster and microwave on one circuit. The code is more then safety though, it includes convenience, longevity of installations and ability to add circuits. Breakers have only so many trips in them before they are worn out. Real big ones have counters for # of trips. DukeKenneth Duke Masters
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I wouldn't worry about it, for several reasons. Firstly, the NEC doesn't prohibit multiple receptacle outlets on 240V circuits - that's one of those "common knowledge" things that's long on common, but short on knowledge. The NEC recognizes multiple outlets on circuits up to 50A (210-3, if memory serves), and larger under certain circumstances, with no voltage restriction (though where voltage restrictions do show up in the Code, it's typically 277V to ground or less, which is 480V three-phase!).
As mentioned just above, you're just as likely to run your toaster, countertop microwave, and coffee maker at the same time, but nobody's requiring individual (dedicated) branch circuits for each of those - the requirement is only for two or more circuits serving counter tops, with the implication that you and I will exercise some judgement to reduce the likelyhood of circuit overload beyond what assurance having two circuits with no specified distribution or arrangement brings.
Secondly, even if you run several machines simultaneously, you can only put a load on one at a time (DC excluded), and the idle (or no-load) current is generally pretty small. There isn't a high risk of overload if it's your own home shop; certainly no more than when running the TV, lights, computer, vacuum cleaner, and space heater all on one 120V branch circuit. A little common sense goes a long way here (not to be confused with "common knowledge" as used above <g>).Be seeing you...
Any hints on folding that stuff in nicely? Get a bigger box and a cover plate..
Hi duke one since your a retired electrician what is your experiance with federal pacific panels? As a Realtor, home inspectors are always calling those saying they are a safty problem due to breakers that don't always trip when they are supposed to.ThanksTroy
Edited 10/6/2005 5:36 pm ET by Troy
Troy: Federal Pacific also had a bad reputation, mostly for loose connection between the breaker and the panel. Kinda funny cause their brand name was/is ''Stab-Lock'', they do stab in but don't lock so well. Most other brands besides F.P. and Zinsco have decent reputations. I am fond of Square D ''QO'' for most lighter loads and ''QOB'' (bolt on) for commercial and lighter industrial panels. The larger stuff, molded case breakers, are mostly made to higher standards. Nowadays these have electronics built in and do all sorts of tricks. Thanks for the opportunity to talk this stuff, my brain is full of info which is not much use in retirement. 3000 amp breakers anyone? DukeKenneth Duke Masters
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I can't plug my 5 HP Unisaw in either. It's hard-wired on its own dedicated circuit (The panel is only few feet away, so it acts as the "disconnecting means" required by Code).
30A isn't enough for a 5 HP motor. It needs to be 125 percent of the full load current rating for that horsepower level, as listed in Table 430-148. The Table lists it as 28A, so you need a 40A branch.
These saws have big motors. My shop and house are on separate 200A services. But the house lights still blink when the Unisaw is turned on. The local power utility says this is within their power quality parameters for single phase motors this size.
My motor's plate lists it as 21A at full load, so 30A is plenty. Also 30A is what Delta recommends, and my code guy has signed off as well. I think I'm OK there.
I'm also using the breaker as the "disconnecting means"; it's only 10' away.
Man, I hope I don't get any blinking when I turn on the saw! I've got a 225 panel but only a 200A meter base.
I'll post back once this is up and running. :)
My motor's plate lists it as 21A at full load, so 30A is plenty. Also 30A is what Delta recommends, and my code guy has signed off as well. I think I'm OK there.
I just looked at the Delta manual online. It says the 5 HP should have 40A overcurrent protection (I thought I remembered reading that). According to the Table in 430, the conductors should be #8. But the inspector is god, and if he wants to ignore that, he can.
Some causes of blinking are beyond your control. In my case, it is caused by the transformer supplying the house and shop. As far as the utility is concerned, it's within spec, so I just have to live with it.
Well I'd better check it again, thanks! It's not too late for me to run 8/2 instead, and get a 40A breaker. I had gotten my information from Delta tech support. I'll look at the manual too!
You may just have saved me a real problem, thanks!
As to the blinking, if it happens it happens. I guess it depends on the CT and the juice supplied there.
Thanks again!
Well, it's not quite as easy as it sometimes seems. :)
A 40A time-delay fuse is not the same thing as "40 OCP". I'm not really clear on the details either, but the fact is that a breaker is more ready to handle the increased load that comes at startup of a motor than is a fuse. I called Delta tech support and posed this exact question, and while they recommend a 40A slow-blow FUSE, they recommend a 30A CIRCUIT BREAKER, and its accompanying 10 ga. conductor. So Delta recommends a 30A breaker, and that isn't contradicted by the 40A fuse recommendation in the manual.
You reference NEC table 430.248, which gives typical amperage for motors based on horsepower. This table is necessarily imprecise, as it ignores both power factor and efficiency. There's no need to consult this table for full-load draw if the motor plate provides it! Not all motors described as 5 HP have the same electrical characteristics or current needs. I agree with you that if my motor in fact drew 28A at load, I'd need a 40A (rounded up from 35A) circuit.
The motor plate says the motor draws 21A at load. Given the rule of thumb for planning the circuit for 125% of full spec load, a 30A circuit (rounded up from 26.25A) seems to be as robust as necessary.
That, plus the inspector's OK (he's been an electrician for decades) with all these facts in hand, makes me happy with installing the 30A circuit as planned.
I don't consider the inspector god (except for the power he has to reverse the long-standing dictate "Let there be light" should he disapprove my installation). I might go more conservative than he recommends, if I think there's a safety issue. But I'm convinced the 30A circuit is safe.
Thanks for the opportunity for me to check my facts!
PS I think the truth of this depends on whether your TS is considered a "motor" or an "appliance". Check this post out, which supports your view. Sort of. Following his reasoning, I'd install #8 conductors but a 30A breaker. With the route I've taken, if I replace the motor and its plate rating is >24A, I'll have to rewire. :)
Edited 10/7/2005 3:37 am ET by vulcan666
A 40A time-delay fuse is not the same thing as "40 OCP".
As far as the NEC is concerned, it is. The ampacity for wires protected by a circuit breaker is the same as when they are protected by a fuse.
Re-reading the manual, I noticed they specify #10 wire. But a 40A fuse, which is not to Code. I think Delta is playing fast 'n loose with the specs, and just specifying a 40A fuse to avoid nusiance blowing of the fuse. If you are using #10 wire, then your OCP must be 30A.
I've got big wire going to mine, and the label in the controller says you can use up to a 70A branch circuit, so I'll stick with my 40A.
Enjoy your saw. You'll probably be perplexed at all those stories from table saw owners who complain about the saw stalling when cutting 8/4 oak. ;) Yours won't even skip a beat.
You're right, 40A time-delay fuse is 40 OCP. But... not all 40A protection is alike, nor is all 30A protection. Again, I think they are saying that the 21A-rated motor draws too much current for 30A fuses, even slow-blow, so they recommend 40A time-delay. Like you, no way I'd put 10 ga. wire with a 40A fuse! And I'm dead positive my inspector wouldn't allow it either.
Enjoy your saw. You'll probably be perplexed at all those stories from table saw owners who complain about the saw stalling when cutting 8/4 oak. ;) Yours won't even skip a beat.
Well, I was originally looking at a Craftsman 22124, the price of which went up to $999. I figured, $1K for that, might as well go up a notch and pick up enough power not to worry. 3HP, here I come.
So I got some advice from folks on various 3HP cab saws (in another thread), was going to land there (Unisaw, maybe Grizzly or General), then found a killer deal on a new 5 HP Bies Unisaw for $1899 delivered, minus the $100 rebate put it in my garage for under $1800 net. I just couldn't pass it up, and I feel that though I may accessorize, I probably won't ever have to *replace* the saw.
There was a recent discussion about the nameplate rating of Unisaw motors compared to the numbers in NEC table 430-148 (which is now table 430-248 in the 2005 NEC, by the way): http://forums.taunton.com/tp-knots/messages/?msg=25931.1
Edited 10/6/2005 3:49 pm ET by Stuart
(if you press on it, the house lights blink!)..
Get that fixed ASAP.. Fire in a home is a bummer...
That said I'll shup up...
Well, George, no need to "shut up". I posted asking for comments, after all, and besides I agree with you 100%. I've already bought the replacement panel; the inspector is coming for a plan review today, and I'll be getting estimates from electricians tomorrow and Saturday.
Your caution is definitely going to be heeded.
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