Hello!  I just bought a 3-footer fluorescent light from the junk shop complete with bulb (for $4), seems to be from  around 2001.  It works just fine when I connect the 120v hot and neutral wires...however, the on/off switch is disconnected and I can't turn it off.   When I looked up the way my old fluorescent Alkco exit sign was wired, I hooked one black wire from the switch to the hot, and the other black wire from the switch to the white neutral (the switch has two black wires).  I powered it on, and immediately the circuit breaker downstairs tripped for my bedroom (but oddly, the GFCI outlet I plugged it into did not trip).  So, evidently, I f*****-up my connections.  

Can anybody tell me how the on/off switch is supposed to be wired? The rest of the light is all connected and working.  All I have to work with that are bare unconnected wires is the neutral wire, the hot wire from the ballast, the ground wire, and the two black wires from the switch.

Thanks!

put your switch(if it survived) in series with the black(hot) lead.

 Hello there

  I see extactly what you did, you created a short circuit. That why it trip the breaker when
when you flip the switch. rember this Black wire is the hot wire comming and the white wire
 is the 0 voltage or Return wire that get sent back to the transfromer out to the pole
 

  Black wire coming IN to switch Out of Switch Black wire to black wire to the ballast input
 the white wire is the return so that goes to the ballast and or lamps, what ballast type
 you have in there? remember this Black to black white to white= no sparky and breaker tripping
  white to black or black to white you just asking for trouble.


  black ------------Sw  Sw------Black------===========
  White------------------------------------=========== this set up is for rapid start Instant start ballast.

  Preheat F30 ballast will have a white wire that go to the lamp holder on one side the tube shared with the Ballast.

Internal wiring in the fixture may not be of the correct colors by the code (at least here the manufacturers can use whatever colors they want for the internal wiring of appliances). In the other fixture (which you copied from) it might be that the manufacturer had white wire to spare so he used that for the wiring from the switch to the ballast etc. What is important is the role of the wire and not its color

In all cases the switch should be wired as in Funkybulb's explanation - instead of the live (normally black) going straight to the fixtures' contents, you connect it to the switch and then from the switch to where it should go to

It has one of those big block instant-start ballasts.  "Robertson" i think it is.  Running on a Philips F30T12 30-watt bulb, from the Alto collection, according to the label.

EDIT:   It works!   Thanks Funkybulb!   Do all fluorescent fixtures work this way?   Because I have two Akco fluorescents, and on each of them, they have two black wires going to the test switch. Each one takes two bulbs, and both of them do not light up. Do those need to be hooked up the same as this one?

There are different ballasts out there that are to be connected differently. The ballast should have a drawing how to connect it, If not, try to find another fixture with identical ballast that works and copy the wiring

Post a picture of the fixture that does not work and how it is wired inside

 @ Seberhusky


  All american wiring for Home wiring is black wire for Hot/Live wire. this is the same for wiring fluorescent
lights. celing fans. electric motors. just imagine this what a switch is your just cutting the wire in the same place and reconnecting it back in place in the same place.

 ok here is on with a switch. Think of it As your a electron trying to cross the Bridge to the other side.
 
  black wire ----------------/------/------------ballast_____________________White wire

  here is Off on a switch. the Bridge is up due being turned off. electron cannot cross this Bridge.

 black wire -----------------/      /------------ballast______________________White wire