They don't anymore, and for a reason.
For a reason.
Your opinion isn't going to matter if someone gets hurt. It's a lot easier to wire a separate circuit.
Their lawyers are dumber than stumps if they think paperwork is going to get them out of the inevitable lawsuit. Do they have a compliance (UL, etc.) mark on them?
You're perfectly within your rights to knowingly violate codes. No "grandfather" excuse here, either.
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Yes, that reason is Code. Having worked on various Standards groups over the years, there's a definite tendency to continue to make modifications simply for the purpose of appearing to continue to do something and thereby justify the existence of the body.
In the 100 years before, where's the overwhelming evidence it was ever a problem????
As I said, one can choose but it's certainly not a major actual problem or there wouldn't have been the history of successful applications (and lord knows how many still existing appliances????) w/o any issues.
When's the last time you _EVER_ heard of it being the cause of anything?
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Huh? Voltage is just potential. You need power to do work, and the amount of power (and thus the amount of work that can be done) is the same in each case.
Faster startup implies that the mechanical work of spinning up the motor is done in a shorter amount of time. This means either the motor is more efficient at 240V or else it's drawing more power. In both cases this would be due to motor design, not simply higher voltage.
Chris
You generally need a ground but only need the neutral if you are using the split phase (the 120V part). So, 240V will usually have three wires (if there aren't any 120V loads) or four (with 120V loads).
Be careful, "ground" and "neutral" are different things. "Ground" is used for safety purposes only. "Neutral" is a current carrying conductor. If there is no current in the neutral (as is the case in a purely 240V circuit) there isn't any need for the conductor. ;-)
Just out of dumb curiosity, does this mean if you don't split off 120, you don't need a neutral? Normally, with 120 you need 2 wires plus ground, hot, common and ground. I don't know zip about 220 but are you guys saying 220 can have 2 wires, both hot, plus a ground (no common), and you connect one of the hots to the light, and what normally would be common or neutral to the ground? I'm in the dark here, just asking. Doesn't 220 always need a common ground (neutral?), just like 120?
Jack Stein wrote: ...
By NEC it now does to be Code-compliant.
For roughly 100 years, split-voltage appliances such as ranges, dryers, etc., used (and were Code-compliant!!!!) the ground as neutral for the
110V side.Only w/ a relatively recent Code revision was this changed to require the 4-wire connection in all cases.
While granted it's not current Code, there are zillions of appliances still in service and certainly a fair number of drill presses and other machine tools wired the same way. There's absolutely no evidence they have been a major safety issue in that time period.
Hence, while granted it's no longer within _current_ Code, there's little real justification for that change being a big deal.
$0.02, etc., etc., ...
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Sure, but it might not be worth the hassle.
To do it properly you'd need a 3-conductor plus ground cable, with a
4-prong plug. Two hots, neutral, and ground. Bring the main cord into a junction box mounted to the tool somewhere. In the junction box split the wires out appropriately to the two motors. The main motor then gets driven by the two hots, while the feed table gets driven by a hot and the neutral.The ampacity of the conductors must be suffient to provide for both the feed table and the main motor, so you'd probably have to increase the conductor size. You'll likely need to add a special 4-prong receptacle, also wired with large enough conductors.
It's probably easier to just zip-tie the two cords together so that they don't get tangled.
Chris
... They say "don't ask us" because of the the revised NEC Code requirements discussed in the upthread subthread sidebar discussion.
In all likelihood previously they would have simply used the three-wire appliance-style arrangement and all would have been happy; now they can't do that and as Chris explains the hassle of the four-wire connections they result was they probably decided simply the two-cord solution was the easiest for them and still meet current Code.
As for what to do; depends in large part on whether you're in a situation where your shop does have to be current-Code-compliant or this is a personal shop. I gather your situation is probably the former so you probably don't want to take the expedient way out and so the only real choice is probably to either live with it as is or rewire to the four-conductor supply.
How much of a pain and what you would have to do physically is dependent on the shop wiring extant now as well as the sizes of the various motors involved.
In short, as Chris says, you can but it may not be worth the hassles despite the other existing hassle.
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Very good. With the net, one never quite knows...
Yes, there is. How easy it will be depends on whether the 240V circuit (not "220") supplying the machine has a neutral or not. If not, you'll need a new circuit.
Assuming that you have a four-wire 240V circuit available (two hot legs, neutral, and ground), install a 4-conductor receptacle on that circuit, and a
4-conductor plug and cord on the machine. Connect the planer motor to the two hot wires; connect the feed-table motor to one of the hot wires (it doesn't matter which one) and the neutral wire. Connect the ground wire to the frame of the unit.
Yes, that's right. That's why the motor will start more quickly with higher voltage.
Another alternative is to add a second lamp of identical wattage and wire them in series.
That is incorrect. Pure 240V circuits do *not* need a neutral conductor.
No, only in those cases where the circuit supplies both 240V and 120V loads.
Two ways. First, you can use a 220/110V transformer (do the voltage conversion the hard way). Second, you can note that the motor may have series-connected windings for 220V, one of the motor internal wiring taps has 110V on it when the motor is operating. That means your light goes off when the motor is switched off, of course...
My preference would be to use a 12V halogen worklight, and get the 220 to 12V version of transformer for it. The 12V lamps are more vibration-resistant, and you have to have the transformer anyhow (no real difference in cost, though some suppliers might not price it that way).
The NFPA is known to write the "code in blood". Someone was injured or killed before the code was modified. Sure, you'll likely get away with it but it is *NOT* smart to knowingly flaunt the electrical code. Lawyers love it, even if you don't kill anyone.
Depends on your definition of "overwhelming". It was never a good idea to tie a current carrying conductor to the case of a device. That's essentially what you're advocating.
Absolute nonsense! There are many dangerous practices that are no longer acceptable. This is one.
When I was *nailed* off my MIL's dryer (after she'd been complaining for months I took a look at it). Had it a safety ground it would never have shocked anyone. The code wasn't changed for this one instance (that they never knew about).
Just don't do it, and stop telling others to violate safety codes! You're being irresponsible!
Power is proportional to the *square* of the potential.
Not more efficient, but does have more *power* available, all else being the same.
I'm not sure if "dpb" was referring to me, or not, but I found that with my DP. Motor can be rewired for 240, but the wiring harness has no provisions for a neutral feed. The "stock" harness connects the work lamp across the two non-ground leads so that if the DP is plugged into a 120v circuit, the lamp socket sees 120. And if plugged into a
240v circuit, the socket sees 240v. I'd strongly suspect the OP's band saw is similar. He'll certainly find out if he rewires the motor for 240 and his work light (with a 120v bulb) burns very brightly for a very short time.Several years ago, on the manufacturer's web site, the PDF manual for the DP, as a part of the diagram for rewiring the tool for 240, showed the work light socket being changed to connect across one hot lead and the EGC to provide 120 to the lamp. I went back to the site at a later date, and that part of the diagram was no longer there. It now shows only a configuration that connects the lamp socket across the non-ground leads with no direct connection to the EGC. I suspect the diagram was deleted as a result of UL requirements.
Using the EGC for an operational conductor does violate the current NEC. But, the NEC doesn't cover anything beyond the wall plug. It's only applicable to permanent wiring, so rewiring the DP (or band saw) to supply 120v from a 2+G 240 circuit doesn't technically violate the NEC unless the device is hardwired into the facility wiring. That doesn't mean it's any more or less safe, just that it's not covered by the NEC. That's according to my understanding of the scope of the NEC. Even if "plug in" loads was covered by the NEC, compliance would be impossible to enforce unless you had to pull a permit and get an inspector out every time you plugged the vacuum cleaner into the living room wall socket.
Using the tool's EGC for a neutral return will, as stated, energize the grounded portions of everything connected to that circuit, as well as everything on every circuit which has an EGC connected to the ground bus in the panel that houses that circuit. The voltage on those energized grounds will be the product of the resistance to ground of the panel's ground bus times the current flowing from the ground bus to ground. May or may not be dangerous depending on the amperage and the resistance to ground.
Incidentally that is the same condition that exists if any device drawing current through that panel develops a short to ground. Until the breaker trips (assuming the leakage to ground is enough to trip the breaker) every grounded item in, or connected to, that panel will be energized with that amps x resistance voltage.
The use of GFI breakers addresses that condition by tripping anytime there is a very small difference in the amperage in the two non-EGC conductors. Otherwise the fault current would have to be on the order of the breaker rating. A DP or BS rewired to use the EGC as neutral on a 240v circuit would certainly trip any 240v GFI breaker that monitored the current in the two hot wires the way a 120v GFI breaker monitors the current in the hot and neutral wires.
Tom Veatch Wichita, KS USA
No. Speaking in the context of "normal" residential, single phase
120v/240v service, circuits that supply only 240v do not need or use the neutral. Only the 120v circuits use the neutral wire. Multiwire circuits that supply both 240 and 120 do need the neutral to support the 120v loads.Tom Veatch Wichita, KS USA
Not likely. Typical dual voltage motors are set up such that two windings are in series for 240v and in parallel for 120v. So regardless of the supplied voltage, the voltage drop and current in each of the windings is the same in either case. In other words, the working parts of the motor don't know the difference between the motor being connected to 240v or 120v.
Tom Veatch Wichita, KS USA
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