I have a big 6'x4'x3' enclosure (glass and wood) for my Tegu monitor. The external magnetic ballast for my fluorescent light broke and I would like to replace it with an electronic ballast. The external magnetic ballast plugged into an outlet, was not grounded, and did not require a ground. The electronic instant start ballast I would like to purchase requires a ground, but my fixture has no metal hood or any metal at all. If I attach the ground wire from 12/3 electrical wire, coming from an outlet, to the ballast metal housing with a screw, would that provide a proper ground? I would have a 15A 125V ground plug on the end so I can plug it into the wall. The electronic ballast would not be mounted and would be external to the fixture due to heat. Thank you!

Edit: I went ahead and purchased an extension cord and electric instant-start ballast. I hooked everything up but the light won't come on. I tried 3 different new bulbs and ran continuity checks with the wires and internal connection points. I'm not sure why it's not working. Here are some connection pics. Thanks.

Edit: Everything works perfectly now. I did not know that electronic ballasts do not use a starter even after all of my research. I clipped and capped the ends where the starter was connected and the light worked perfectly.

  • That sounds like the way to do it. Welcome to Home Improvement. You can take the tour at diy.stackexchange.com/Tour to get the most out of this site.
    – SDsolar
    Jun 17, 2017 at 15:16

2 Answers 2


Get a programmed-start ballast.

Cheap ballasts also misuse ground to manipulate capacitive effects between the fluorescent tube and the metal enclosure. Note huge assumption about fixture design.

Programmed-start ballasts preheat the fluorescent lamp filaments (in the ends of the tubes) until conditions are ideal to strike the arc in the manner Tesla intended. It results in a 0.5 to 3 second startup delay (depending on ambient temperature) but is very easy on the tube, and avoids the capacitive trick.

Heat will be minimal on any modern ballast. In a fluorescent, the heat comes from the tubes.

You may want to think about LED lighting and do an end-run around all these problems.

You can't use NM cable as cordage. If you want cordage, buy cordage. They often sell it with a socket premolded onto the end, marketed as an "extension cord". Make sure the writing on the side of the cord is legal for cordage, then SNIP!

  • I have to buy this stuff today to give my lizard proper UVB lighting. Unfortunately, I can only find an instant-start ballast that I can go pickup right now. I will order a programmed-start ballast and use that when it comes in, but I'm going to use an instant-start ballast until I get it. I'll go pickup this extension cord. I'll pickup some 12/2 romex in case the ballast wire does not reach my fixture since it's external. Thanks alot.
    – Touc
    Jun 17, 2017 at 16:49
  • The issue with the instant-start is the ballast may not start, particularly once the bulbs get old. If it does start, you can put off buying the better ballast. I get them on eBay for $10ish. Jun 17, 2017 at 21:11
  • I tried 3 different new bulbs with the instant-start ballast, but none of the lights will come on. I opened up the ballast and tested all of the lines coming in and out with my continuity function on multimeter. After running that continuity test I am confident that all of my connections are secure. Is it possible that my fixture just doesn't work with electric instant-start ballast? connections to and from ballast
    – Touc
    Jun 18, 2017 at 0:08
  • the problem may be what I warned about: the ballast needs something electrically grounded to be running parallel to the tube about 1" away, i.e. the metal reflector most fixtures have. . You could probably fake it with a length of ground wire. Also make sure the ballast is wired correctly to the lampholders, it is quite different. For each end of the lampholder, take both wires and tie them to each other and also to the wire from the ballast. A programmed start ballast will want two wires to each end, so don't tear them out lol. Jun 18, 2017 at 1:49
  • I ran some ground wire coming from the ballast ground connection next to the fixture and even tried having the end of the wire touching the case of the fixture, but the light wouldn't come on. I went ahead and ordered the same magnetic ballast I had before since I know it will work.
    – Touc
    Jun 18, 2017 at 15:43

The electronic ballast is intended to be connected to the safety ground wiring of building. In most modern buildings that ground is provided via a connection at the outlet as you have mentioned. So yes the cord with three prong plug is your starting place.

Even if your enclosure was made of metal or had metal parts it would not be sufficient to simply connect the ballast to those metal parts without them being in turn connected back to the safety ground at the outlet.

When you mount up the ballast and cord wiring make sure to so that in a safe way so that there is no chance of accidental damage to the wiring and that it is enclosed in suitable covering or box. The attached cord should be strain relieved so that tugs on the cord do not compromise the wiring connections.

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