Mysterious Purple wire

[steven57079]

Came across something i cant quite figure out why was done

I was just starting to prep some existing electrical boxes in an office area for partitions that have wire mold factory installed and upon pulling the blank plate off the box I noticed I had a red, white, green and purple wire inside the box. Grabbed my meter and confirmed both wires have 120v to ground. My first thought was it was going to be a multi wire branch circuit but the label only identified one single circuit. Tested between the two wire and read 0. Went to the panel and shut off the circuit, both wires went dead. I was very confused at this point as to why both wires shut off.

Went to the next blank and found a black, white, green and (again) purple. Tested the same way and same results.

I found this all the way down the wall.

I attempted to take the dead front off the panel but the screws were seized on.

I am just curious if anyone ran across this before and what is the purpose of having the purple wires on the same circuit. A coworker suggested shunt trip breakers but I don't believe the breakers were shunt trip nor would I think breakers labeled "future modular furniture" would need shunt trip breakers on them.

TIA

 

[Dennis Alwon]

Is it possible that the purple wires are switched somewhere?

 

[CoolWill]

Just another hot wire sounds like.

 

[steven57079]

Is it possible that the purple wires are switched somewhere?

Well there are 12 individual circuits in the room and each one contains a typical circuit color and a purple. I didn't notice a bank of switches or a contactor in the electrical room

 

[steven57079]

Just another hot wire sounds like.

But why!!!??? its a 20a circuit with 12 wire. no need for a parallel run

 

[infinity]

Tested between the two wire and read 0

Since you have 120 volts from hot to ground from both the black and purple conductors but 0 volts between them that means that they are connected to the same phase. Did you open the panel?

 

[steven57079]

Since you have 120 volts from hot to ground from both the black and purple conductors but 0 volts between them that means that they are connected to the same phase. Did you open the panel?

The screws were seized on but i might try an impact hammer screw driver today

 

[infinity]

The screws were seized on but i might try an impact hammer screw driver today

At least that will tell you if the purple conductors originate at a circuit breaker. If not then they're spliced somewhere.

 

[jim dungar]

The fact they are colored purple means nothing.
The fact they are a different color means theY served a different purpose than the normal color.

Maybe they were intended to provide both switched and unswitched receptacles in the modular furniture, but it is not implemented.

 

[infinity]

Maybe they were intended to provide both switched and unswitched receptacles in the modular furniture, but it is not implemented.

A switch leg would be my guess too.

 

[CoolWill]

But why!!!??? its a 20a circuit with 12 wire. no need for a parallel run

Pre-wired office furniture usually has multiple circuits. Somewhere both circuits come together. Unless you need the capacity of multiple circuits, it doesn't seem to be a big problem.

 

[roger]

Early in my career purple was common for switch legs and travelers.

 

[ModbusMan]

Can't speak for other areas, but in Columbus, purple/violet was used for 480/277 B-phase wye (as opposed to orange, which was B-phase high leg delta)

 

[CoolWill]

Can't speak for other areas, but in Columbus, purple/violet was used for 480/277 B-phase wye (as opposed to orange, which was B-phase high leg delta)

That's also what I tend to do as well, but it isn't codified any place I know of. I doubt furniture manufacturers even gave it any thought at all.

 

[hillbilly1]

Can't speak for other areas, but in Columbus, purple/violet was used for 480/277 B-phase wye (as opposed to orange, which was B-phase high leg delta)

I think it’s still yellow brown purple in Texas, but pretty much everywhere else changed to brown orange yellow. The change came about due to brown and purple is hard to distinguish in low light conditions such as above ceilings, along with the decline of delta high leg services. I recently used yellow brown purple on a new 1600 amp service because the old 400 amp service was a 240 delta high leg.

 

[hillbilly1]

Modular furniture can have pink and other colors too, usually denotes general purpose, dedicated or even “clean power” circuits.

 

[curt swartz]

Are any of the receptacles marked "controlled"? As others have stated it could be for switched receptacles controlled by occupancy sensors in areas where required.