Ok, dumb question. I need help from a learned sparky out there, in very plain english tell me the difference between a 3 phase outlet and a 4 phase outlet. (In very simple terms does 3 phase = hot,hot,neutral and 4 phase = hot,hot,neutral,ground. Now, nobody worry I’m not touchin’ anything, just settling an argument at work. (we push pencils).
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You're confusing "outlet" with "service" Residential services in the US almost all have TWO phase 120/240 services. Two hots, a neutral and a ground. You can then wire a 120 or 240 volt outlet, using one hot leg and a neutral for 120 both hot legs and NO Neutral for 240. Big appliances like ranges, dryers, and water heaters sometimes need BOTH 120 and 220, so those outlets will get a neutral too.
Sometimes a domestic garage, farm or workshop will have THREE phase service, I think three hots, a neutral and a ground...so then you would have an option, I think, of wiring three hots into an outlet, but probably most three phase wiring is hard wired into a big motor, like 3+ hp.
Pros, please step in here...I just testing my knowledge.
Don't let whoever told you that do your wiring. Single phase is a single hot wire with respect to a neutral. 2-phase is two hot wires where the sine wave is inverted (180 degrees out of phase) on one wire. The neutral may physically exist or may not. 3-phase is 3 hot wires, with phases 0, 60 and 120 degrees. If there is a neutral, this is a "wye" configuration. If no neutral, it's a "delta". You draw power between a hot wire and neutral or any between any two hot wires. Ground is actually the potential of the earth. A connection to a rod driven into the ground. Its for protective purposes. The neutral is actually connected to ground at ONE point in the system.
You're talking about a range outlet. The old way was 220 2-phase with neutral and no ground. Three wires. Ground is sort-of-approximately-somewhere-around neutral. Not close enough to neutral that you can't get a shock if there is a wiring or appliance problem. The new range outlets require 220 2-phase, neutral and ground. 4 wires. Ground goes to the appliance chassis so you don't get fried if there is a wiring fault.
The new range outlets require 220 2-phase, neutral and ground. 4 wires. Ground goes to the appliance chassis so you don't get fried if there is a wiring fault.
The new electric wall ovens run their panels (& the oven light) from a 120 circuit within the appliance--which is possible with the 4 wire connection.
Grounding is the safety reason the codes have changed. Convenience is why the appliances changed. Good all around.Occupational hazard of my occupation not being around (sorry Bubba)
Bob,
4 phase is where you go when you grab the 0 degree leg in one hand and the 120 degree leg in the other hand, isn't it?
Clampman
That's where the rule of keeping one hand in your pocket came from. Just so long as you don't have any holes in your pocket. Then its something else entirely.
Since we're asking dumb questions -
I've never heard of "4 phase". Does such a thing actually exist?It is a miserable state of mind to have few things to desire and many things to fear; and yet that commonly is the case of kings. [Francis Bacon, Essays]
On the railroad some of the older GE electrics were 4 phase.
Who ever invented work didn't know how to fish....
Theoretically you could make 4 phase, or any other number of phases. I don't know of any current widely used applications other than single phase and three phase.
Many years ago, Tesla experimented with true two phase, the legs being at 0 and 90 degrees.
But the important and hard to grasp point is that a neutral and two hot legs 180 degrees apart is actually single phase, not two phase. Plot the two sine waves on the same axes, and you get zero crossings (in opposite directions) at the same points, and no area between the curves, so no power at all at those zero crossings. That's the whole point of polyphase power, to have no dead times.
Wye connected three phase has a neutral and three hots, with the neutral "centered" between the hots. You might see 120v from neutral to each hot and 208v between pairs of hots.
Delta connected three phase has the neutral midway between a pair of hots, sort of like single phase for those three wires, with the "wild" phase 208 volts from neutral and 240 from the other hots, IIRC. I only saw a delta system once, in a big 1920's hotel, and those are the numbers I remember.
-- J.S.
In the delta with a neutral halfway between two hots is quite common where most of the load in a building is 120/240 single phase. The third hot is sometomes called the 190 volt leg, because that is what is measures on a voltmeter with the other lead on neutral. This would be typical in small machine, mechanic, and body shops where there are a few 3 phase motors.
Frank