Fluorescent Wiring Question

[AntmanMike]

I am reposting this here because no one has replied in DIY:

I am using 2 Rapid Start T12 40 watt dual bulb ballasts.

I want to have them run 4 20 watt bulbs (2 for each ballast)

Obviously, these bulbs run 20 watts less than what the ballasts are designed for.

I tested my ballast set up on a 15 watt tube, and it gave me snakes and wasnt bright at all, quite dim (medium purple).

Once I put in an old 20 watt that has given off a stable purple on any hood, it had no snakes, and seemed to run more stable.

Would INCREASING a bulbs wattage change the way it acts, and possibly make it brighter? I would assume that 40 watts of power going to a 15 watt bulb would make it super bright, not dim... since on its standard ballast (For a 15 watt) it is quite bright...

 

[AntmanMike]

You know, this thread has been here an hour, and the one in the DIY forums has been there over a day... yet no replies...

 

[hatton3]

There is a looong answer to your question. However, it's not found on this board. Go to www.reefcentral.com and do a search on "overdriving flourescents" in their forum. There was a very large discussion about overdriving bulbs - what it sounds like you want to do - on their board a couple months ago.

What they found was the best way to do this was to have your two bulb T8 ELECTRONIC ballast wired to fire just one bulb per ballast. However, I've got serious misgivings about this, as it is not UL approved and you are getting the same lumens as if you had two bulbs on the circuit. It also appears from your discription and wiring outline that these ballasts may be rapid start, but they are not electronic ballasts. I don't think you can't overdrive a bulb with a tar and coil ballast. That's probably why you were seeing what you were calling "snakes".

I'd be careful, as you don't want to burn down your house with a non-UL approved wiring situation - your homeowners or renter's insurance might not cover any damage from mis-wiring.

I just bought an IceCap ballast so I wouldn't have to worry about fires. It is expensive, but worth every penny IMHO. You can find them used fairly affordably.

 

[AntmanMike]

Nonononono... i am using standard wiring, but the two wires from each ballast I am combining so its easier to wire, then I am splitting at the end... same voltage throughout.

The problem is it is a Dual Bulb 40 Watt Rapid Start Tar ballast.

I was testing it on a 15watt and a 20 watt... and both came on VERY dim and snaky...

I dont think the audio wire i used to wire it is up to par.

 

[carpguy]

I know that when I was wiring up my lights I got dim bulbs and snakes when I accidentally wired them backwards. Switching the wires fixed the problem immediately.

Lamps over a tank of water that I've put a good bit of time and money into, smack dab in the middle of my home, are not a place where I personally would cut corners or try to economize.

 

[AntmanMike]

No... by combining the wires I have less wires hanging everywhere.. i do plan on changing ballasts and wires soon tohugh.... what do you mean by wires backwards? I tested this on another ballast, pure ballast... with the caps already done, and the same thing happened... I was building my ballast box for 12 hours, to make sure i did it right.

 

[carpguy]

When I first tried hooking up my lamps I connected the hotline from the ballast to what should have been the return on the endcap and the return to the ballast to what should have been the hot on the endcap. I wired it "backwards". This gave me a very underpowered wavery light. "Snakes" sounds like a good description of it. When I reversed everything I got the steady intense light I was looking for.

Slip gets busy sometimes but he really seems to me to be the resident expert on this sort of stuff. Given time he should show up on his own, but you might try a PM if he doesn't weigh in after a few days. It would make me very uncomfortable to leave my apartment without total confidence in the lamps. The rest of my family is in fire control and they've instilled in me what they like to think of as a healthy paranoia.

I got little plastic loops that screw into the inside of my canopy (they came with my AH Supply kit, but I've seen similar at the Home Depot). There are no hanging wires to snag on something during maintenance. Wires going to similar places are bundled together but the wiring is very standard and very secure.

 

[AntmanMike]

Could you please draw a simple diagram?

 

[hatton3]

Originally posted by AntmanMike
Nonononono... i am using standard wiring, but the two wires from each ballast I am combining so its easier to wire, then I am splitting at the end... same voltage throughout.

The problem is it is a Dual Bulb 40 Watt Rapid Start Tar ballast.

I was testing it on a 15watt and a 20 watt... and both came on VERY dim and snaky...

I dont think the audio wire i used to wire it is up to par.

Sounds like you are really frustrated with these lights...

If I'm reading your diagram right, I think I know what your problem is:
It looks like you are combining ballast paths together.

You need to have a red circuit and a blue circuit going back into one yellow (orange in your diagram) circuit.

Right now, you have a blue and a blue going into an orange circuit. And a red and a red going into an orange circuit.

Another way to put it. on your diagram, we'll number from the top bulbs 1,2,3,4. Bulbs 2 and 4 need to be on one orange circuit, bulbs 1 and 3 need to be on the other orange circuit.

You have got 1 and 2 (which come from 2 different ballasts) going into your top ballast only. 3 and 4 going into the bottom ballast only.

Make sense?
I've attached a diagram for you. Try and wire one ballast at a time. It might be easier. In the diagram, the black box at the bottom left is the ballast. The two gray boxes are your bulbs. the purple wire is just jumper wires.

 

[hatton3]

I looked at your post in DIY forum. You asked if you could combine all the red wires into one wire. All the blues into one blue. What do you mean by this? If you mean tie them together as a bunch of four with twist ties, yes you can do that. If you mean to splice and wire nut them all into 1 single 18 gauge wire, no you can't do that. You'll run into the same problem that I discussed above. THe reason is because you are shorting out the ballast at the splice and wire nut, right as it leaves the ballast.

If that is what you did in the diagram above, than that's another problem that you need to fix besides the orange wires. You have to keep each circuit by itself.

On a sad note, if indeed this is what you have done, when you do wire up the ballasts correctly, they might not work now because they have been shorted and possibly damaged.

You said that you might want to buy different ballasts in the future. I'd go with electronic ballasts because there will be only three wires for you to fool with. They are wired differently than tar ballasts. That would satisfy your need to reduce wire numbers running in your hood. You can buy electronic ballasts at home depot or lowes for about $20.