Can someone tell me what is the switch and wiring configuration for a 2 switch/2 lamp circuit where one lamp is always ON? This configuration is rarely used, but it IS used, nevertheless, in small apartment buildings where there is a hallway and a long, dark stairway to the upper floor. There are two lights and two switches, one at the bottom of the stairway, and one at the top. One light is ALWAYS on, but not both, so the switches alternate the power from one light to the other or in other words, throwing either switch transfers the power from one light to the other. - thanks, Tony

This is an easy circuit with one switch/2 lamps using a 3 way switch. It's much more complicated adding a second switch, and I have yet to mentally figure out a way to do it without adding components beyond switches and lamps.

Are you sure that this is a safe arrangement? It seems unsafe to me that both lights couldn't be on at once. What happens when the old lady who lives upstairs is on her way down and somebody out of sight flips the other switch so they have light on the hall?

I think you need to re-think what you're trying to accomplish here and consider some alternate ideas. What about an individual switch for each light and a third unswitched light that provides minimal (security) lighting that would prevent the building from being pitch black when the two lights are switched off?

Depending on what you are trying to light and why you are lighting it is extremely important. In general, toggling night lights is never a good idea if it is at all possible that people will be walking in the area when the light cycles.

If it is for just general purposes, like creating an image by shooting the light down a wall and then back up the wall you might be able to get away with the circuit you desire.

However, if there is any concern for anyone's safety whether exiting the building during an emergency or providing protection against criminal acts, then what you want to do may not fly as far as your insurance company let alone fire, NEC and Police codes in your area.

I cannot quote NEC Code, but I believe the security and safety lights must be on separate circuits that cannot be manipulated from outside. They must also be a 24 HR. UPS to come on if the building should lose power.

My suggestion is get a licensed electrician have the work done to code and be done with it. You sure as heck don't want someone falling down because you wanted cheap lighting which failed when you needed it most.

You elect power company or local electrical inspectors might be able do thumbnail this for you, but any licensed journeyman or master can tell you just as fast.

Thank you, Bolt in blue and Don F for your answers and concerns. I left out the part of my circumstance which is that only ONE PERSON is ever in this building even though it can house several. So there's nobody else to be concerned about being left "in the dark." The two lights are both quite bright and either one illuminates the area sufficiently, but it's nice to have it brighter closer to the edges of the stairway, whether you're going up or down. The two switches alternate which edge of the staircase gets the MOST light to avoid tripping. Once the stairway has been taken, flipping the other switch makes it clearer to navigate to either the front door at the bottom or to your apartment door, at the top. When the person leaves, the light will be on for her to clearly see her way to the top of the stairs. Once there, she flips the switch the other way to see clearly the bottom of the stairway and continue her journey down the hall to the front door. Your concerns for safety are well-noted and appreciated. But with only one person in the building and the switch openings already made, as well as the lamps hung, I am interested in developing only this circuit I've described: Two switches, two lamps, one always on. The switches alternate power to the lamps in such a way that only one lamp is on at all times. I hope you can mentally realize the configuration and draw it out for me using simple switch terminal notations. - Again, thank you so much!

This still sounds like a bad solution to me. The code doesn't change whether you have one person living in the building or 20 people. I admire that you're trying to help your resident, but you really need to check with your local government to see if this meets code. Another option would be to hire a licensed electrician (who should be up to date on the code and unwilling to do things in violation of code).

That said, wiring a system as you have described is not difficult. All you need is standard 14/2 (for 15 amp circuit) or 12/2 wire and two 4-way switches. I am happy to answer once you convince me that this building will still be safe with more than one person living in it. I'm not trying to be difficult--just don't want to be even indirectly responsible for someone getting injured due to advice I gave them.

Thank you Bolt in Blue for your legitimate concerns for safety. In order to reduce the amount of text in my original question, and trying to just stay on target, I've excluded what I felt were unnecessary details regarding these hallway landings and stairwell. Your concerns for proper lighting are just and duly noted. However, rest assured they are unwarranted given the COMPLETE story of the lighting situation. You see, these areas are ALREADY well-illuminated with OTHER lights that are controlled individually both at the front door at the bottom of the stairs and at the end of the hall, and outside the upstairs apartment doors, enabling the independent illumination of either area. The two lights I'm presently trying to control at the staircase are more of a spotlight type that brightens just the very beginnings of the case. There is sufficient lighting WITHOUT these lights, but for my elderly mom, I just wanted to make sure she had the ability to clearly see EVERYTHING CLEARLY before she began her decent. Once at the bottom, the throwing of the other switch will increase the illumination of the area between the bottom of the staircase and the front door, which as I said, already has a hallway light installed, but it's right over the front door to aid in the gathering of keys, removal of coats, etc. So while your concerns are appreciated, and justified, this instance is not completely dark to begin with. There already are lights on both the upper and lower platforms. I look forward to hearing (hopefully, SEEING) the wiring configuration of the two 4 way switches you spoke of. A picture is worth a thousand words. Thanks again. Your time and concerns are much appreciated. - tony

Thank you for easing my concerns. One more thing for you to think about is that instead of 2 lights, 2 switches, you may want 2 lights, 4 switches, so that each light can be turned on or off from either location. The reason that you'd want this is saving electricity when these lights aren't needed.

To wire what you have in mind, you'll need two 4-way switches. These switches will have four terminals (plus ground). It's possible to wire it a number of different ways, but I'm assuming power through a switch.

Note that it's important to grab the neutral from the power source before the first switch, since after the first switch, there is no promise which wire is hot and which is neutral. A 4-way switch changes whether the pairs are connected straight through or whether they are crossed. Because either wire can be neutral after the first switch, it is important to mark the white wire with tape so you are aware that it is not neutral. If you used a 12/3 wire between the first and second switch, you could run the real neutral on the white and use the black and red wires for the connections to the first switch.

I do not think that what you have drawn will meet his needs and I don't feel comfortable designing something ad hoc other than in a classroom.

If, as described earlier in this post, on light is to be the primary, always on and the second light will come on as needed, then you may want to consider using a motion detector on the 2nd light so that it provides power to the second light after the person is on the stairs from the top or bottom. Power would have to switch back and forth which is always a problem when you are trying to do things half way.

If the switch locations are close to the point of entry into the space, or even better opposite the point of entry, occupancy motion sensors offer a simple fix.

Look for passive infrared and ultrasonic, picks up heat and sound. Each can be adjusted to go off in one minute up to 30.

Not that the hardwiring is wrong, just a little weird, unorthodox.

Plus, after reading the text, switching a neutral cannot be done in this situation. All conductors need to be opened, which cannot be done with this diagram.