# Help! Sudden Melting/burning Endcaps



## fishstein (Dec 12, 2005)

I'm hoping someone out there can tell me why one of my endcaps "flashed" - the plastic/rubber partially melted to the end of the T8 bulb and scorched the inside of my wooden tank hood a few months ago; and then another end cap started to burn/melt today - I suddenly smelled burning plastic/rubber and noticed it was coming from the hood - and then pulled the power. The heat was high enough on that endcap to partially melt it, burn a hole through the side and fuse it to the end of the bulb.

I suspect that the culprit is either 1) age - that either the endcaps needs to be replaced after many years use or the ballasts need to be replaced OR 2) the ballasts not being able to handle the combination of one bulb at F32 Watt and one bulb at F36 Watt 3) old electronic ballasts that need to be replaced.

I've had these endcaps and electronic ballasts in continuous daily use for about 8 years. Perhaps the endcaps become dry and more vulnerable to heat over time. I do have replacement endcaps on hand, but before I use them I'd like to find out what the cause is.

Currently I'm using the best bulb combination I've ever used - each ballast is running 2 bulbs, one Phillips Aquarelle TL89 F36T8 10,000K one Phillips Advantage F32 ADV850 5000K bulb, for a total of 4 48 inch T8 bulbs in the hood. The hood is well ventilated.

Some possibly important clues:

1) The endcaps that have fried are both on the right side of the aquarium feeding off of the red (hot) white and black wires from the ballasts (the endcaps on the other side where there was no meltdown feed off the blue wires coming from the ballasts). 

2) Also, the first fried endcap was on an Aquarelle bulb; the second one today was on an ADV850. So I'm not sure if it's the bulbs. Perhaps it's the combination of the 36 Watt (Aquarelle) and the 32 Watt (ADV850) on the same ballast. 

3) The first endcap to fry was fed by one ballast; the endcap that fried today is fed by the other ballast.

I'd sincerely appreciate your advice - not just for the health of my tank, but for the safety of my family and other pets!


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## furballi (Feb 2, 2007)

fishstein said:


> I'm hoping someone out there can tell me why one of my endcaps "flashed" - the plastic/rubber partially melted to the end of the T8 bulb and scorched the inside of my wooden tank hood a few months ago; and then another end cap started to burn/melt today - I suddenly smelled burning plastic/rubber and noticed it was coming from the hood - and then pulled the power. The heat was high enough on that endcap to partially melt it, burn a hole through the side and fuse it to the end of the bulb.
> 
> I suspect that the culprit is either 1) age - that either the endcaps needs to be replaced after many years use or the ballasts need to be replaced OR 2) the ballasts not being able to handle the combination of one bulb at F32 Watt and one bulb at F36 Watt 3) old electronic ballasts that need to be replaced.
> 
> ...


It's not a good idea to drive two unbalanced loads with one ballast. I'd change the electronic ballast and check all wiring. Pay attention to age and moisture. Check for good isolation between the driving elements and ground. Most electronic ballast are designed to drive 32 Watt 4' T8.


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## fishstein (Dec 12, 2005)

"It's not a good idea to drive two unbalanced loads with one ballast. I'd change the electronic ballast and check all wiring. Pay attention to age and moisture. Check for good isolation between the driving elements and ground. Most electronic ballast are designed to drive 32 Watt 4' T8."

So I should not be mixing a 32 watt ADV850 bulb with a 36 watt Aquarelle on the same ballast? Would it be better to drive 2 36 watt Aquarelles on the same ballast and two 32 watt ADV850s on the other? It's also possible that my ballasts are not designed to handle the 36 watt bulbs - I might need something a bit more robust.

By checking aging and moisture, do you mean to check moisture and cracking on the wires? There's no visible damage and it's highly unlikely given where the wires are. 

How can I check for good isolation between the driving elements and ground? I'm not an electrician - can you be more specific?

I sincerely appreciate your advice. This is a major safety issue I have to solve.


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## fishstein (Dec 12, 2005)

I ran this question on another planted tank forum and this is what we've come up with so far:

tropicalfish
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Get some cooling fans first!!
__________________
---
75 Gallon
Rena FilStar xP3, Aquarium Systems Visi-Therm 200W (2), Coralife 48" Aqualight 260W 6700K

---
10 Gallon Hexagon
Hagen AquaClear 30, Visi-Therm Deluxe 50, DIY CF 20W 6500K CF, Hagen Natural CO2 System :: Bloodfin Tetra (1), Red-eye Tetra (3), Black Skirt Tetra (3), Harlequin Rasbora (6), Platy (1), Otocinclus Catfish (1) :: Rotala Indica, Hygrophila Difformis (Wisteria), Cabomba Carolina (Cabomba fanwort)
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Old Today, 12:16 AM #3 (permalink)
Fishstein
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The lack of a fan is not the cause - I've used these end caps and the same hood with 4 T8 48" bulbs for years without any problems. Does anyone have any other suggestions?

For all of the years I've run these end caps and ballasts except for the last 6 months, I've used them with 4 identical F32T8 48" Verilux full spectrum bulbs. $ of the same bulb.

A few months before the first end cap fried, I mixed an F36T8 Aquarelle with an F32T8 ADV850 on each of the two ballasts - perhaps running an unbalanced load on each is a problem.
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Old Today, 12:29 AM #4 (permalink)
phkhgh
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Fishstein,

Did you say whether you were using ODNO? If not, are the ballasts mag or electronic? If using ODNO, the caps like yours are covering part of the lamps, which get much hotter than w/ NO. Don't know how good an idea that'd be anyway.

Ballasts can & do go bad. I worked in maintenance during college & replaced a lot. Normally they don't cause probs when going bad, but...
Problems w/ any ballast, esp electronic, could be intermittent - but usually aren't. But I saw a lot that'd work ok for a few days, then act up, then normal again.

Unless you have equip to test current draw, etc., it might be better to replace ballasts. How did the metal connections in the endcaps look (before melt down), and how were the pins on lamps? Make sure all connections are clean, tight and not corroded.

Do you have glass between water & lights? If not, it's a good idea. Were both ballasts same brand / model? If they're mag, don't know how flexible those are for running diff wattage lamps at same time.
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Old Today, 12:47 AM #5 (permalink)
Fishstein
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** Thanks so much for the info. See ** below for answers

Fishstein,

Did you say whether you were using ODNO? If not, are the ballasts mag or electronic? If using ODNO, the caps like yours are covering part of the lamps, which get much hotter than w/ NO. Don't know how good an idea that'd be anyway.

** By ODNO, do you mean over-driven normal output? I don't know how to set that up. My ballasts are simply standard F32T8 electronic ballasts, each designed to handle 2 bulbs. Perhaps the ballasts can't handle the 36 W bulbs or can't handle balancing a 36 watt and a 32 watt on the same ballast. I'll also ask my local lighting wholesaler - I hope they know.

Ballasts can & do go bad. I worked in maintenance during college & replaced a lot. Normally they don't cause probs when going bad, but...
Problems w/ any ballast, esp electronic, could be intermittent - but usually aren't. But I saw a lot that'd work ok for a few days, then act up, then normal again.

Unless you have equip to test current draw, etc., it might be better to replace ballasts. How did the metal connections in the endcaps look (before melt down), and how were the pins on lamps? Make sure all connections are clean, tight and not corroded.

** There may have been some corrosion after so many years, especially since I don't keep glass between bulbs and water. I'll have to check. Is it possible that all I need to do is replace the old end caps that might have corrosion on the leads?

Do you have glass between water & lights? If not, it's a good idea. Were both ballasts same brand / model? If they're mag, don't know how flexible those are for running diff wattage lamps at same time.

** I don't keep glass between the water and the bulbs because it really reduces the quality of the light getting into the water, and my tank, while it's not super deep, is a 75 gallon 48" L by 18" W and 18" H, and with this setup, and the bulbs I have, I can get great growth without using more lights and more power by not using glass. A lot of aquarists I know recommend not using glass between the bulbs and the water. The bulbs are about 6 inches above the water and the hood is very well ventilated by cutouts on the back and top of the hood.
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Old Today, 04:26 AM #6 (permalink)
rich
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Quote:
Originally Posted by Fishstein View Post

Do you have glass between water & lights? If not, it's a good idea. Were both ballasts same brand / model? If they're mag, don't know how flexible those are for running diff wattage lamps at same time.

** I don't keep glass between the water and the bulbs because it really reduces the quality of the light getting into the water, and my tank, while it's not super deep, is a 75 gallon 48" L by 18" W and 18" H, and with this setup, and the bulbs I have, I can get great growth without using more lights and more power by not using glass. A lot of aquarists I know recommend not using glass between the bulbs and the water. The bulbs are about 6 inches above the water and the hood is very well ventilated by cutouts on the back and top of the hood.
I'm sorry to say, but your aquarist friends reccomendations are making your tank electrically unsafe for the sake of a tiny light loss. Using a shield is pretty much necessary in a closed hood. If you're going to suspend lights above an open tank with a good air space, it might be better. I'm not sure who would tell you to suspend a light 6 inches above the water with no shield. This very well could be the cause of your short circuit - one fish breaking the surface of the water or a particularly high evaporation cycle would be all it would take to douse a fluorescent endcap with water. If you're worried about light problems, you can make a shield out of acrylic or fused quartz as they interfere very little with the spectra, but you need something in there to isolate the electrical system from the water area.

-Rich
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Old Today, 09:16 AM #7 (permalink)
WibblyPig
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Did you have the little gaskets in place and are you using waterproof endcaps? If not, there may have been corrosion in the endcaps which caused arcing.
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Unread Today, 10:56 AM #8 (permalink)
Fishstein
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I'm using Coralife/Energy Savers water-resistant end caps (water-resistant, not waterproof). I am 99% sure the problem emanates from corrosion in the end caps.

I once dropped one of the end caps (when it was off) in the tank and though I let it dry for two days, that was the end cap that originally fried a few months later. As for the other end cap that fried, that was probably related to cumulative corrosion in the end cap over a period of 8 years. I think my best first bet is to replace the end caps with either new water-resistant end caps (I have enough spares to replace them all), or better yet, to replace them with fully waterproof end caps (just saw Ice Cap waterproof end caps for T8 here: http://www.aquariumplants.com/Ice_Ca...ir_p/ic738.htm ). Anyone know of any other waterproof end caps worth checking out?

Two things that I'd like to verify:

1) whether or not the ballasts can safely handle one 36 watt and one 32 watt on each ballast - in other words, can the dual F32 electronic ballasts handle the mixed wattage - everyone I asked in electronic stores when I bought them said yes. But I want to double check.

2) I have glass shields that go over the top of my aquarium water. However, they are very thick (about 1/4-1/3 inch glass) and do cut a lot of light, and are a real pain to keep clean and clear; they also keep the water temp higher and cut down on gas exchange to keep good oxygen in the water. What I might consider, if it was safe, is to use clear T8 tube covers the likes of which I have on my 48 in. F32 T8 Verilux full spectrum bulbs that I have in ceiling fixtures in my home office. These are clear tubes that cover the entire bulb and protect it from splashes, dust, etc. and protect people from a shattered bulb. The Question is whether these plastic sleeves, when used inside a hood (granted a hood with a lot of the back cut out for ventilation), keep too much heat around the bulb. Anyone ever use these clear plastic tube shields inside a hood?


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## fishstein (Dec 12, 2005)

I'm 99% certain at this point that the issue was just corrosion in the end caps after many years use (and in the case of one end cap, from a dunking in water) - they've been in use for more than 8 years over water. I'll share anything I find out from my local electronics suppliers as well. Using waterproof end caps rather than my water resistant end caps would probably help.


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## fishstein (Dec 12, 2005)

This is what a poster in the other planted tank forum suggested just now:

"It's not a ballast/bulb combo problem and cooling fans won't stop it. The problem is the contacts in the endcap are loose. This causes a bad electrical connection, which makes for a high resistance and it sometimes arcs and always gets hot. You may be able to "squeeze" the female connectors in the endcaps a little with pliers to tighten them up. It's a common problem on molded endcaps for a lot of types of lighting."

Either it's a loose connection and/or corrosion in the end caps. Both explanations are highly likely.


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## Muirner (Jan 9, 2007)

Thank you for all the good research. I run 4 x 32watt T8 Philips on my canopy. BUT, i've wanted to add a different bulb or two into the canopy because of the CRI of the philips daytime deluxe bulbs. I'll be watching my endcaps very closely to see if i find anything of the sort...

BTW Where did you get your flourcent fixtures?


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## fishstein (Dec 12, 2005)

I built them - picked up the electronic ballasts at the local electronic/lighting store and the end caps from That Fish Place (they are Coralife/Energy Savers water-resistant). Then I took some cheap extension cords to make the extra wiring I needed, and used electric tape to make the connections. I never had a problem for more than 8 years until this end cap issue.

I'm 99.9% the issue is the end caps - either corrosion or bad connection.

I spoke with several electronics suppliers - all said that there should not be a power issue with the F32 watt dual ballasts running a 36 W and a 32 W - what winds up happening is that your 36 W is a little underpowered what it could be. But given how bright it is already, and how amazingly beneficial the Aquarelle wavelength is for photosynthesis and for highlighting certain colors in your tank, believe me you don't need that few watts of extra power.


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## fishstein (Dec 12, 2005)

By the way, I did find out Ice Cap makes waterproof end caps, which might not be a bad idea, and I might use polycarbonate tubes with very thin walls to protect the tubes and electric leads from moisture and corrosion (see my post on the polycarbonate tubes in this same forum).


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## furballi (Feb 2, 2007)

fishstein said:


> "It's not a good idea to drive two unbalanced loads with one ballast. I'd change the electronic ballast and check all wiring. Pay attention to age and moisture. Check for good isolation between the driving elements and ground. Most electronic ballast are designed to drive 32 Watt 4' T8."
> 
> So I should not be mixing a 32 watt ADV850 bulb with a 36 watt Aquarelle on the same ballast? Would it be better to drive 2 36 watt Aquarelles on the same ballast and two 32 watt ADV850s on the other? It's also possible that my ballasts are not designed to handle the 36 watt bulbs - I might need something a bit more robust.
> 
> ...


I'd check the specs on the new ballast to see if it is rated for 36 watt. Most commercial stuffs have a 10% tolerance, so you're probably okay. Yes, I would not run a 32 watt and a 36 watt off of one ballast.

I would expect more oxidation at the ends of the wire since these are exposed to higher than average humidity. Copper will turn green when oxidized. You may want to tin all copper terminals apply RTV silicone to improve corrosion resistance.

Use an ohm meter to check the resistance from the power terminals to ground (usually the metal reflector). Anything under 100 ohm is suspect. Also make sure the body of the ballast is grounded to the 3rd round prong of your AC plug.


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## fishstein (Dec 12, 2005)

furballi said:


> I'd check the specs on the new ballast to see if it is rated for 36 watt. Most commercial stuffs have a 10% tolerance, so you're probably okay. Yes, I would not run a 32 watt and a 36 watt off of one ballast.
> 
> I would expect more oxidation at the ends of the wire since these are exposed to higher than average humidity. Copper will turn green when oxidized. You may want to tin all copper terminals apply RTV silicone to improve corrosion resistance.
> 
> Use an ohm meter to check the resistance from the power terminals to ground (usually the metal reflector). Anything under 100 ohm is suspect. Also make sure the body of the ballast is grounded to the 3rd round prong of your AC plug.


Hi Furballi,

Thanks so much for the tips. However, I checked with several electronics suppliers and they think that there is absolutely no problem with running a 32W and a 36W bulb off the same dual F32 electronic ballast - all that happens is that the 36W is slightly underpowered, which doesn't matter, since it's a very high efficiency bulb which throws a lot of light that is highly beneficial in photosynthesis.

Questions:

1) How exactly should I ground the body of the ballast? Just tie a wire around it and insulate it with electrical tape and run the covered wire to the third prong of the outlet? And are you sure this should be done if the wiring instructions provided no instruction for doing this?

2) How can I tin all copper terminals? With a soldering iron and raw tin soldering wire?

3) Where can I get RTV silicone to improve corrosion resistance and how would I apply it?

I tend toward adopting the simplest and least expensive solution that will work - taking everything into account, I think that the very simplest and least time consuming things to do are:

1) replace my end caps, either with the water-resistant ones I have (6 of 8 have lasted +8 years without problems) or, for $40 total, replace them with fully waterproof end caps. The problem appears to have originated from corrosion from moisture inside the end caps.

2) use polycarbonate tubes to cover my T8 bulbs to help prevent moisture from reaching the end caps and to protect the bulbs. This is simpler and easier for maintenance that using the glass tank covers I have.


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## furballi (Feb 2, 2007)

fishstein said:


> Hi Furballi,
> 
> Thanks so much for the tips. However, I checked with several electronics suppliers and they think that there is absolutely no problem with running a 32W and a 36W bulb off the same dual F32 electronic ballast - all that happens is that the 36W is slightly underpowered, which doesn't matter, since it's a very high efficiency bulb which throws a lot of light that is highly beneficial in photosynthesis.
> 
> ...


I look at it from a design/reliability point of view. Most commercial stuffs can handle +/-10%, but only with a balanced load. Will it work? Yes. Will it last as long as a balanced load? No. You could put four 195/60/15 tires from Michelin, Goodyear, Kumho, and BF Goodrich on your car, but that would not promote a good handling vehicle.

If each ballast is designed to drive a pair of T8s, then you should closely match that pair of T8s for best performance and stability.

UL certified ballast should come with a green wire. Connect this green wire to the ground prong of your AC plug.

Use 60/40 solder or equivalent and a soldering iron (about 30 watt) to tin the copper wire. Home Depot has RTV silicone. Apply a 1/8" to 1/4" coat to cover unprotected metal surfaces. There is no such thing as a waterproof end cap. Normal condensation will cause metal to oxidize.

I always put a glass cover on top of the aquarium and leave a 1" air gap along the length of the aquarium for gas exchange. My T8s sit 1.2" above the glass. Never had any corrosion issue.


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## MemphisBob (Mar 20, 2007)

1. Most endcaps will not withstand being "tinned" and still function properly. They're plastic and will either melt from the iron's heat or the copper "springs" that contact the bulb's pins will lose tension. 

2. Solution is to replace all endcaps then lubricate new hardware (pins and prongs) with dielectric grease if you're concerned about corrosion. Dielectric grease is available at auto parts suppliers.

3. For safety's sake remove all electrical tape connections as well. Those are prone to corrosion also. Use a wire nut with a touch of the grease in it to make the connection tight and clean.


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## fishstein (Dec 12, 2005)

MemphisBob said:


> 1. Most endcaps will not withstand being "tinned" and still function properly. They're plastic and will either melt from the iron's heat or the copper "springs" that contact the bulb's pins will lose tension.
> 
> 2. Solution is to replace all endcaps then lubricate new hardware (pins and prongs) with dielectric grease if you're concerned about corrosion. Dielectric grease is available at auto parts suppliers.
> 
> 3. For safety's sake remove all electrical tape connections as well. Those are prone to corrosion also. Use a wire nut with a touch of the grease in it to make the connection tight and clean.


Hi Memphis Bob,

Great advice. Thank you very much. I was concerned about melting the plastic in the end caps. Do you know where I might be able to get dielectric grease online? Is there a particular brand name under which it would be marketed?

I had been using electrical tape and you are absolutely right that while the tape connections were not inside the hood but under the tank, it's still a good idea to replace them with a wire nut.

Do you know where I can buy some wire nuts? I just haven't bought electronic parts in ages except for my ballasts and wires.

Have a few other questions, will post later today. Again, thanks for the great advice.


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## MemphisBob (Mar 20, 2007)

http://www.autoaccessconnect.com/digr.html
Dielectric grease. No O'reilly's in NYC? Any auto parts retailer should have Permatex or another brand.

Hardware stores will the place for wirenuts as well as wherever you buy ballasts/wires.

Corrosion of the endcaps most likely did cause your original flashing.


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## fishstein (Dec 12, 2005)

Hi Furballi,

I'm almost done refurbishing my hood. I'll have all the materials hopefully by this weekend. However, I checked and my UL approved Sylvania ballasts never game with green grounding wires to ground the ballast body to the third prong of a plug. I'll have to attach a wire to do this - do you know where on the ballast I should attach it and with what? Is there an electrical wire nut that can be used to secure the grounding wire to the ballast? 

To share some good things I found out:

1) I hated using the 2 heavy glass shields (1/4 inch glass) that came with my 75 gallon aquarium and stand, which I bought second hand in great shape from someone moving out of town quickly. It was a pain (with danger of dropping and breaking them) to move them out of the way whenever I wanted to go into the tank. I checked with several sources, including lighting design companies and a plastics engineer, and it turns out that light, cheap 1/8 acrylic will give me better light transmission than the 1/4 inch glass and weight almost nothing. I'm cutting two pieces to go over the two sides of the tank. They should be easy to clean and easy to move.

2) Every end cap manufacturer should post a warning about failure of end caps from corrosion. Two highly experienced longtime aquarium specialty planted tank/reef aquarium staffers I spoke with said that all end caps eventually fail due to corrosion and/or poor contact, resulting in arcing and melting, and they loved the idea of using dielectric grease to protect the leads, which I told them I learned in this forum. I plan on posting this warning on the equipment and lighting forums. Perhaps it should be added as a sticky for lighting setup.


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## fishstein (Dec 12, 2005)

Hi Memphis Bob,

Thanks again for the great suggestion of using dielectric grease. Fantastic idea.

I'm looking for as small a quantity as I can get my hands on because a lot of us folks in NYC don't bother keeping a car (rental is only 2 blocks away for when we need).


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## angry gary (Jul 26, 2007)

no matter what the verdict on the meltdown, there is a more dangerous issue here. fire. i have replaced every outlet in my house that ANY aquarium accessories plugged in with GFCI. the next time it happens,(and i hope it never does),it will just trip the outlet overload and that will be enough of a warning to tell you something ain't right.

AG


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