# Master on/off with independent on/off light switch diagram

I'm trying to figure out a way to have:

3 banks of lights, each with individual switches for ON/OFF independent of master switch position.

One master ON/OFF switch that HAS to turn all other switches off, but not necessarily ON.

Practical example:

Workshop with 3 worktable lights and various corners of shop. I want to be able to turn each work light on as needed without turning the others on, but want to be able to turn all off at the end of the day with one switch by the exit. In the morning when I return, if I forget to turn the master switch "ON" I would like to still be able to turn the work lights on without having to go back to the master switch. Is this possible with out relays? Some sort of fancy 3-way switch matrix?

• Walking is good exercise. More you forget, the more exercise you get. Keep it simple with a main power switch for lights or whole workshop that needs to be on to have light/power. Jun 10, 2021 at 18:36

Could this be done with a bunch of relays or smart switches? Sure. But a lot of work for little benefit.

Keep in mind that generally speaking for safety (and often by building code rules) you should have a switch near the door that always turns at least one light on. If, through some combination of relays and switches, the master switch turns everything off but when turned back on doesn't turn anything on then in an emergency you are hunting for additional switches.

The two simple solutions (but not exactly what you asked for) are:

• Each light is a 3-way switch with one set of switches at the main entrance and the other switches at each workstation. This means possibly three throws to turn everything off, but is simple and intuitive for anyone using the room.

• Master switch that turns on a circuit which controls:

• One light that is on - e.g., a central ceiling light
• One switched light at each workstation.

With this arrangement, the master switch turns everything off. When turned on, the central light goes on and any workstation lights return to the previous settings. Unless this workshop is also used for watching movies on a big screen TV, the central light should not cause a problem, and the power usage with LEDs will be minimal.

You could also combine this and have one master switch + 3 3-way switches, for maximum flexibility. But that may be a bit more confusing to new users.

## This isn't quite as hard as it sounds

While this sounds like it'd require a bunch of relays and other assorted kit to get done, it really doesn't, as it turns out, thanks to a handy-dandy thing called the SweepSwitch. These are made by Acuity (the folks behind Lithonia Lighting, if you know that name), and are a standard illuminated-OFF toggle switch with a twist: interrupting power to them for more than 5 seconds cause them to flip mechanically back to the OFF position. This is intended to be used to provide a local override for central lighting control panels, but can be abused in more localized applications like yours with the help of a few other commercial lighting control doodads.

In particular, you'll need one SSPL 05 277 for each local control location, in addition to a Legrand/Wattstopper A120C-P or equivalent (Form C) powerpack and a Leviton 1080 momentary toggle wall switch at the "master" location. Power is brought in at the master location, feeding both the black HOT and the brown COMMON wires on the powerpack, while the white NEUTRAL wire on the powerpack connects to neutral. The red +24V and blue +SW wires on the powerpack connect to the "master" wall switch, while our outgoing switched-hot connects to the blue NC wire on the powerpack, and the red NORMALLY OPEN and black -0V wires on the powerpack are capped off individually. With all this done, the master switched-hot is simply fed to the individual SweepSwitches controlling individual lighting loads.

This limits us to 5A of fluorescent or LED lighting load overall because the NC contact on the powerpack is used to "invert" the momentary-NO operation of the toggle switch to work around the fact that non-center-off momentary SPDT wall switches are not a thing. A larger load could be handled by using a heavier-duty relay/powerpack and 20A SweepSwitches, though; either way, you'll have to order the parts through an electrical or lighting supply house, as this is rather beyond what you'd find at the home-improvement store.

## Sure. You can have the "master switch" be a 3-way complex

So you have the master switch location. And then, you have locations of satellite switches which are subordinate to the master switch. (i.e. fed from its "switched-hot" line).

At each of these satellite locations, also put a master switch.

Connect all the master switches with a massive 3/4-way switch complex. No matter where you are, you can switch the whole shebang on and off from any location.

This also means if you finished the day with lights C and D switched on, and shut the master off, then when you go to A and switch on the master, lights C and D will come right back on. You will need to physically go to C and D to shut them off.

If you want C and D to have automatically shut off and stay off in that scenario, now you're into relays.

Although really in this day and age, you do that with smart switches. Heck, since I'm guessing these are tool lights, and most of the machine tools I know have lights with a separate cord and a NEMA 1 plug (and often a NEMA 1/5 convenience receptacle on the machine for that light), you can just use smart switch plug-in modules and don't have to hardwire anything at all.

The only way I see to do this is with a programmable system where all switches are inputs to a PLC that controls things the way you want.

I do not think it can be done with 3way 4 way combinations because of your requirements.

sure relays could do it that’s all a PLC is (programmable logic controller ) with simple outputs.

Yes there are products out there that can be programmed but be prepared for sticker shock a complete system that meets your requirements will run ~3k it could be a bit higher but with discrete switches no way.

My estimate may be off a bit as it has been a few years since installing this type of system and am guessing at the cost reducing because the tech is old now.

Programmable smart lights may be a better way to get what you want and can be controlled by your phone.

You don't mention turning the individual lights off independently.

Each workstation light can be fed through a relay that "seals in", i.e. once activated it supplies power to itself. A momentary N.O. pushbutton at each location can energize the relay after which it will remain closed. (A second momentary N.C. pushbutton can be wired in ahead of the relay as an "off" button. Pressing it removes power from the relay causing it to drop out.)

The master is a momentary N.C. pushbutton that, when pressed, removes power from all of the relays. Any energized relays will drop out. Since the master is momentary there is nothing to reset or turn back on, the workstations are ready to go as soon as the master is released.

Depending on the loads and switches, you might want the master pushbutton to activate a relay that provides power to the other locations.

The relay portion of the circuit can be replicated as needed for the workstations. The Master Off pushbutton is common to all workstations.

Note that the On pushbutton has to carry the lighting load inrush current as the relay is energized. A relay with a second set of contacts would allow you to separate the load from the pushbutton. Similarly the Master Off pushbutton carries the load of all of the lights and must be capable of interrupting the load. A master relay could be used to separate the lighting load from the Master Off pushbutton.