Converting 120V Tube Lights to 240V

[brycenesbitt]

Oooh, this is a weird one. I have a commercial lighted sign wired with #14 wire and tombstones to
conventional florescent bulbs, at 120V. This needs to be converted to a 240V feed. Now how to do this without creating a mess:

1. Convert the tombstones to 240V and get 240V T8 bulbs. Put a nice big sign in the sign saying 240V only.
2. Use a 240V to 120V transformer and the neutral becomes... not sure.
3. Feed a new neutral through 1000 feet of rusting conduit that's already at max fill and has been there decades.

Anyone see a better option? The feed is hot/hot/ground with no neutral, fed from a 20A 240V breaker and running other 240V sodium lamps.

 

[LarryFine]

There are no 120v or 240v fluorescent tubes. Only the ballast input sees the supply voltage.

Check the label of the ballast(s) you have now. If they're rated only for 120v, get new ballasts.

It doesn't matter that one ballast wire is white; you can still supply it with a line-to-line source.

You don't need to mess with the tubes or the tombstones; they have nothing to do with this.

 

[brycenesbitt]

There are no 120v or 240v fluorescent tubes. Only the ballast input sees the supply voltage.

Sorry I was imprecise.
I would of course be removing the ballasts completely regardless, and using 120V-240V direct wire LED tubes in the T8 form factor. I'm just unsure if I'm supposed to put 240V over the two ends of a tombstone that originally had the tube voltage, due to the potential for confusion among a future service person. I can see someone tossing a floro tube, or a 120V fixed voltage tube in....

One connector, so many voltages.

 

[LarryFine]

Sorry I was imprecise.
I would of course be removing the ballasts completely regardless, and using 120V-240V LED tubes in the T8 form factor. I'm just unsure if I'm supposed to put 240V over the two ends of a tombstone that originally had the tube voltage, due to the potential for confusion among a future service person.

Aha. Most LED tubes are now rated 120-277v, and should come with stickers for the fixtures.

Ballasts have outputs of several hundred volts, so the existing wires and tombstones are fine.

 

[kwired]

the tombstones are likely rated 600 volts.