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[iwire]

there are "advanced level" DIY's on this site who's user names I recognize from other sites. They've been bluffing here for years,

No way.....can't happen....

 

[roger]

Okay, I'm a DIYer, Homeowner, Have a valid drivers License, and I am not spending weekends in Jail.

I don't fit the electrician mold at all, do I have to leave now?

Roger

 

[Rockyd]

Roger,

Way I heard the requirements for a journeymen were the following -

1. Do time time on the road.

2. Do a divorce.

3. Do time in jail.

If you did these, we'll see if you have any electrical talent!

PS I'm still lacking on filling my "ticket". Can I stay if I promise to only comment on electrical issues?

 

[charlie b]

That was several good questions, Julie, and a few nonsense ones that I am sure you threw in just for the entertainment value. But I think I can answer a couple:

And why is it called a 4-way if you need one when you have only 3 switches? Why aren't 3-ways called 2-ways?

The word ?way? does not refer to the paths that current can take, after it leaves the switch. It refers to the number of contact points within the switch. A regular on/off switch has two contact points. Current comes in on one contact point, and the switch arm (not leg) will either stop the flow of current or pass it along to the other contact point. In a three-way switch, current comes in on one contact point, and the switch arm will carry it either to the second point or to the third point. In a four-way switch, there are two contact points on one side and two contact points on the other side, and there are two switch arms. I can?t easily describe how it works, and I don?t have a picture handy. Perhaps someone else can finish this story.

And how come 120/240 is called single phase, but 120/208Y is called three phase?

The term ?phase? refers to the phase angle of any one current, with respect to the phase angles of any other currents that share the same wiring system. In a 120/240V system, you can say that the current in one leg is exactly in phase with the current in the other leg. It is essentially a continuation of the same current, and that is why it is called ?single phase.? Depending on how you define the two currents (i.e., which way is ?positive current?), you could say that the currents in the two legs are exactly 180 degrees apart in phase angle. But that does not change the ?singleness? of the phase configuration.

In a three phase system, like the 120/208V system, the currents in the three legs are distinctively separated from each other by 120 degrees of phase angle, or (if you prefer) by one third of a cycle.

Whatever happened to 2 phase?

It exists, but it is no longer popular. I do not even know when or why it was ever used. All I know is that the phase angle between the two currents was 90 degrees.

 

[tallgirl]

Charles,

I was playing on the apprentice who asks "Why?" then gets whacked in the head

I was reading up on 2-phase power last night, on account of I didn't want to ask silly questions that would then look like serious questions. It was an interesting stroll through the history of power distribution around the turn of the previous century. Here's an interesting article on History of two-phase system. Neat stuff.

In a four-way switch, there are two contact points on one side and two contact points on the other side, and there are two switch arms. I can’t easily describe how it works, and I don’t have a picture handy. Perhaps someone else can finish this story.

My understanding is that a four-way is wired internally like a DPDT switch, but there are internal connections which "cross" the two poles when the switch is thrown the other way. So, if you have I1 and I2 (inputs one and two), they'd normally be connected so that I1 went to A1 and I2 went to A2, then when flipped it would be I1 to B1, I2 to B2. Basic DPDt behavior, except with the internal wiring it's I1 to O1 and I2 to O2, then because what would be B2 is connected to O1 and B1 is connected to O2, flipping the switch gives you I1 to O2 and I2 to O1. This flips the two travellers that come in, so if current was flowing on I1 on input, it's routed to O2 on output, and vice versa. Getting back to the 3-way, recall that it switches it's only input (I) between O1 and O2. They then becomes the inputs to the 4-way, which is going to swap them around. Those outputs can go to an infinite number of 4-ways downstream, before finally getting sorted out at the terminating 3-way where the travellers are now the inputs and the switch selects which of the two travellers is connected to the output terminal. What this means is that the 4-way switch is the universal switch -- you can wire it as a 2-way, 3-way or 4-way, whereas the other two cannot.

Makes sense?

 

[Jim W in Tampa]

Charles,

I was playing on the apprentice who asks "Why?" then gets whacked in the head

I was reading up on 2-phase power last night, on account of I didn't want to ask silly questions that would then look like serious questions. It was an interesting stroll through the history of power distribution around the turn of the previous century. Here's an interesting article on History of two-phase system. Neat stuff.



My understanding is that a four-way is wired internally like a DPDT switch, but there are internal connections which "cross" the two poles when the switch is thrown the other way. So, if you have I1 and I2 (inputs one and two), they'd normally be connected so that I1 went to A1 and I2 went to A2, then when flipped it would be I1 to B1, I2 to B2. Basic DPDt behavior, except with the internal wiring it's I1 to O1 and I2 to O2, then because what would be B2 is connected to O1 and B1 is connected to O2, flipping the switch gives you I1 to O2 and I2 to O1. This flips the two travellers that come in, so if current was flowing on I1 on input, it's routed to O2 on output, and vice versa. Getting back to the 3-way, recall that it switches it's only input (I) between O1 and O2. They then becomes the inputs to the 4-way, which is going to swap them around. Those outputs can go to an infinite number of 4-ways downstream, before finally getting sorted out at the terminating 3-way where the travellers are now the inputs and the switch selects which of the two travellers is connected to the output terminal. What this means is that the 4-way switch is the universal switch -- you can wire it as a 2-way, 3-way or 4-way, whereas the other two cannot.

Makes sense?

Last 4 way i seen only had 2 positions ,but then so did that single pole.

 

[George Stolz]

I don't care if it has two independent sets of contacts or one that pivots in the center - I leave that to the manufacturer.

There's got to be a test pattern to think about or something, I'll see what I can dig up.

 

[Jim W in Tampa]

I don't care if it has two independent sets of contacts or one that pivots in the center - I leave that to the manufacturer.

There's got to be a test pattern to think about or something, I'll see what I can dig up.

So if we have two 3 ways and two 4 ways do we have a 5 way or is that an orgy ?

 

[George Stolz]

If we're going to talk about four-ways, here's a question:

From left to right, looking at a wall with switches in it, can I have...

• A threeway with power in the first box (14/2 in, 14/3 travellers out),
• A fourway with a switchleg in the second box (2x 14/3, 1x 14/2),
• A fourway in the third box (2x 14/3),
• A threeway in the fourth box with a switchleg (three-gang box, other switches on the same circuit in the box that are powered within that box)

...and have both sets of lights come on at the same time?

There, at least that's better than dissecting a threeway.

 

[Jim W in Tampa]

If we're going to talk about four-ways, here's a question:

From left to right, looking at a wall with switches in it, can I have...

• A threeway with power in the first box (14/2 in, 14/3 travellers out),
• A fourway with a switchleg in the second box (2x 14/3, 1x 14/2),
• A fourway in the third box (2x 14/3),
• A threeway in the fourth box with a switchleg (three-gang box, other switches on the same circuit in the box that are powered within that box)

...and have both sets of lights come on at the same time?

There, at least that's better than dissecting a threeway.

Only if installed on days that end in Y

Lets see i picture of this and then we will tell you.I can run wires to 5 differant dead end switches and control 20 lights.

 

[tallgirl]

Last 4 way i seen only had 2 positions ,but then so did that single pole.

And so did the last DPDT I saw.

 

[tallgirl]

If we're going to talk about four-ways, here's a question:

From left to right, looking at a wall with switches in it, can I have...

• A threeway with power in the first box (14/2 in, 14/3 travellers out),
• A fourway with a switchleg in the second box (2x 14/3, 1x 14/2),
• A fourway in the third box (2x 14/3),
• A threeway in the fourth box with a switchleg (three-gang box, other switches on the same circuit in the box that are powered within that box)

...and have both sets of lights come on at the same time?

There, at least that's better than dissecting a threeway.

I think you have enough four-ways there to do just about anything you want. In particular, depending on the position of the second 4-way, you can either have two lights on and off together, or on and off opposite.

 

[George Stolz]

I think you have enough four-ways there to do just about anything you want.

How do the number of four-ways aid in switching?

In particular, depending on the position of the second 4-way, you can either have two lights on and off together, or on and off opposite.

How would you have two sets of lights come on opposite?

Can you draw the two circuit paths?

 

[tallgirl]

How do the number of four-ways aid in switching?

The four-ways act as magical 3-way reversal switches

How would you have two sets of lights come on opposite?

Can you draw the two circuit paths?

I don't have anything that draws nice pretty circuit diagrams.

Recall that on a normal set of 3-way travellers one of them is hot and the other is not. So, you feed the switch and then either traveller A or B is hot. Right?

When you go into the 4-way, what comes out as A' (the new A) is either A (the "A" traveller from the 3-way) or B. Which means that A' may be the same as A, or A' may be the same as B. In other words, A can be hot or not and B can be hot not, and so can A' or B', regardless of which one of A or B is hot. One of those is the switch leg, let's pick A'. When A' is hot, the first light is on.

A' and B' go into the second 4-way where it comes out A'' and B''. Depending on the position of that 4-way, A'' is either A' or B', and B'' is either B' or A'. And we know, because all a 4-way does is reverse which traveller is carrying the current at the moment, that we can pick A'' or B'' to be hot, regardless of which one of A' or B' is hot. So, if the first light is on, A' is hot, if not, B' is hot. If I want A'' to be hot I just flip the switch accordingly.

When you get to the final 3-way, I assumed the two travellers from the 4-way were wired to the two screws on one side of the switch, and the switchleg was off the other screw. The switchleg is connected to either A'' or B'', and as you know, either A'' is hot, or B'' is hot. And whichever is hot is independent of A' (the first light) being hot.

Really interesting collection of switches you've got there.

 

[George Stolz]

Let's assume for a moment we want both sets of lights in this switching to come on and go off at the same time.

So, for the switchleg coming out of the 2nd switch (4way), you'd tie it to one of the screws of the fourway? What happens when the other fourway is flipped - the lights would be out of sequence, wouldn't they?

You've got twelve hours to figure it out.

(As we proceed in this, bear in mind this switching method may cause EMF and should be avoided. Also, it's a violation of KISS. )

 

[tallgirl]

Let's assume for a moment we want both sets of lights in this switching to come on and go off at the same time.

So, for the switchleg coming out of the 2nd switch (4way), you'd tie it to one of the screws of the fourway? What happens when the other fourway is flipped - the lights would be out of sequence, wouldn't they?

You've got twelve hours to figure it out.

(As we proceed in this, bear in mind this switching method may cause EMF and should be avoided. Also, it's a violation of KISS. )

Yes, they'd be out of sequence -- but that was the point of my earlier remark. Now, instead of being in sequence, they are in opposite sequence.

And I agree this is too complicated, especially since you can do what I described (lights on and off together, or on and off opposite) with a pair of 3-ways. You've got 12 hours to figure that one out

(Oh, and while I enjoy a snipe hunt and brain teaser as much as the next person, if all I cared about was a pair of lights coming on and going off together, I'd stick with a single 1P and be done with it.)

 

[Jim W in Tampa]

Dont turn them loose yet george.Make them sweat a few more days.Thanks for the PM

 

[George Stolz]

I'm with Jim, I'm not turning it loose that easy.

Let's assume our switches are a demand of the customer, or more compelling, a building code issue for this house. There is a huge lam seperating two halves of the kitchen, and there are multiple doors into the house.

The lam is forcing you to pull switchlegs from two different points.

I think you can figure it out.

 

[kspifldorf]

To all this concerns... Very interesting reading opinions and facts. Great tool to keep oneself in check and up to date. Thanks KEG

 

[acrwc10]

George, I think if they start giving tests to post on this site. You would deffinately weed out the DIY's if you are so tasked. I think you sure got Tall jumping through hoops, its almost painful to see.But nice work on both sides.