4 tube fluorescent wiring

[captainwireman]

On a typical four tube fluorescent fixture there are the line in white and black. There also are pairs of red, blue, and yellow for a total of eight ballast wires.

For our purposes, lets call the tubes outboard pair and inboard pair with N and S ends.

Why does one yellow feed the S ends of the inboard and the N ends of the outboard? Would it not be less complicated to feed one end of the tubes with a yellow for the inboard pair and the other yellow for the outboard?

I have a theory but I was hoping to hear your reasoning.

 

[captainwireman]

I was trying to say:

One yellow feeds the S inboard tubes, the other yellow of the pair feeds the N outboard.

 

[kwired]

Maybe just a carry over from the T12 magnetic ballast days?

Then you had 2 ballasts resulting in multiple pairs. By running same colors of each ballast to opposite ends you would not connect the wrong ballast to the wrong lamp as easily.

I recently put in several 4 lamp fixtures but can't recall if the yellows went same or opposite ends. Seems like all the yellows are typically on same end if a 4 lamp ballast is installed, but will be opposing if multiple ballasts are installed.

 

[captainwireman]

This is the wiring style on the newer single ballast fixtures. I have consistently seen it on different manufacturers fixtures. Which brings up another question. Is this wiring style typical?

My guess is this evens out the flicker or pulse? Does the pulse from a fluorescent tube start at one end and end at the other end of a tube or does the gas excite evenly over the full tube at once?

 

[GoldDigger]

This is the wiring style on the newer single ballast fixtures. I have consistently seen it on different manufacturers fixtures. Which brings up another question. Is this wiring style typical?

My guess is this evens out the flicker or pulse? Does the pulse from a fluorescent tube start at one end and end at the other end of a tube or does the gas excite evenly over the full tube at once?

If the tube were running on pulsed DC, there would be a difference between the aging at the two ends.
But in this case, the only possible difference will be which end of the tube has a filament heated cathode compared to a cold or arc current heated cathode.

 

[kwired]

If that arc is AC current it will not matter it is starting at both ends 60 times a second. If the arc is DC current it will always flow one direction.