Timer for metal halide
Can anyone provide guidance on how large a timer I need for a 400W
metal halide grow lamp? The vendor suggested a 15 amp grounded outlet, the stated he likes 20 amps ones. However, I recently ran across some nice, grounded 10 amp, outdoor timers ( Intermatic . On the side they list capcaity as 1200 amps R Resistive or 1200 amps Tungsten. I know that Metal halides are different, but do I really need a 15 amp timer or will these 10 amp ones work? Thanks Mike |
Timer for metal halide
Mike wrote:
Can anyone provide guidance on how large a timer I need for a 400W metal halide grow lamp? The vendor suggested a 15 amp grounded outlet, the stated he likes 20 amps ones. However, I recently ran across some nice, grounded 10 amp, outdoor timers ( Intermatic . On the side they list capcaity as 1200 amps R Resistive or 1200 amps Tungsten. I know that Metal halides are different, but do I really need a 15 amp timer or will these 10 amp ones work? Thanks Mike I use the cheap ungrounded ones; they last a year or two before the contacts burn out -- just like the expensive heavy duty grounded ones. I haven't tried the electronic timers, like what I have a bunch of fluorescents plugged into, but they should work too. Bob |
Timer for metal halide
Mike, I use an Intermatic heavy duty grounded timer for two 430 watt lights and another maybe 160watts of power. I'm guessing it cost maybe $10 or $12. I think it's rated for 1600 watts. Bought it years ago (maybe 5 or 6) at Menards, a home improvement chain in our area (MN-WI). The timer is not in my growing area so is not subject to constant humidity. It is plugged into a GFI protected 20 amp outlet. I'd vote for the 15 amp timer. You probably dropped a couple hundred plus for the light, I wouldn't skimp on the timer, though maybe I did? Bob "Mike" wrote in message m... Can anyone provide guidance on how large a timer I need for a 400W metal halide grow lamp? The vendor suggested a 15 amp grounded outlet, the stated he likes 20 amps ones. However, I recently ran across some nice, grounded 10 amp, outdoor timers ( Intermatic . On the side they list capcaity as 1200 amps R Resistive or 1200 amps Tungsten. I know that Metal halides are different, but do I really need a 15 amp timer or will these 10 amp ones work? Thanks Mike |
Timer for metal halide
Mike, I use an Intermatic heavy duty grounded timer for two 430 watt lights and another maybe 160watts of power. I'm guessing it cost maybe $10 or $12. I think it's rated for 1600 watts. Bought it years ago (maybe 5 or 6) at Menards, a home improvement chain in our area (MN-WI). The timer is not in my growing area so is not subject to constant humidity. It is plugged into a GFI protected 20 amp outlet. I'd vote for the 15 amp timer. You probably dropped a couple hundred plus for the light, I wouldn't skimp on the timer, though maybe I did? Bob "Mike" wrote in message m... Can anyone provide guidance on how large a timer I need for a 400W metal halide grow lamp? The vendor suggested a 15 amp grounded outlet, the stated he likes 20 amps ones. However, I recently ran across some nice, grounded 10 amp, outdoor timers ( Intermatic . On the side they list capcaity as 1200 amps R Resistive or 1200 amps Tungsten. I know that Metal halides are different, but do I really need a 15 amp timer or will these 10 amp ones work? Thanks Mike |
Timer for metal halide
Mike, I use an Intermatic heavy duty grounded timer for two 430 watt lights and another maybe 160watts of power. I'm guessing it cost maybe $10 or $12. I think it's rated for 1600 watts. Bought it years ago (maybe 5 or 6) at Menards, a home improvement chain in our area (MN-WI). The timer is not in my growing area so is not subject to constant humidity. It is plugged into a GFI protected 20 amp outlet. I'd vote for the 15 amp timer. You probably dropped a couple hundred plus for the light, I wouldn't skimp on the timer, though maybe I did? Bob "Mike" wrote in message m... Can anyone provide guidance on how large a timer I need for a 400W metal halide grow lamp? The vendor suggested a 15 amp grounded outlet, the stated he likes 20 amps ones. However, I recently ran across some nice, grounded 10 amp, outdoor timers ( Intermatic . On the side they list capcaity as 1200 amps R Resistive or 1200 amps Tungsten. I know that Metal halides are different, but do I really need a 15 amp timer or will these 10 amp ones work? Thanks Mike |
Timer for metal halide
Mike, I use an Intermatic heavy duty grounded timer for two 430 watt lights and another maybe 160watts of power. I'm guessing it cost maybe $10 or $12. I think it's rated for 1600 watts. Bought it years ago (maybe 5 or 6) at Menards, a home improvement chain in our area (MN-WI). The timer is not in my growing area so is not subject to constant humidity. It is plugged into a GFI protected 20 amp outlet. I'd vote for the 15 amp timer. You probably dropped a couple hundred plus for the light, I wouldn't skimp on the timer, though maybe I did? Bob "Mike" wrote in message m... Can anyone provide guidance on how large a timer I need for a 400W metal halide grow lamp? The vendor suggested a 15 amp grounded outlet, the stated he likes 20 amps ones. However, I recently ran across some nice, grounded 10 amp, outdoor timers ( Intermatic . On the side they list capcaity as 1200 amps R Resistive or 1200 amps Tungsten. I know that Metal halides are different, but do I really need a 15 amp timer or will these 10 amp ones work? Thanks Mike |
Timer for metal halide
(I also don't know what they mean
by '1200 amps R Resistive or 1200 amps Tungsten', but you are nut if you think you're going to put 1200A into anything safe.} Mike meant to type "Watts" rather than "Amps". The "Resistive" rating refers to a constant resistive load. The "Tungsten" rating refers to a (tungsten filament) incandescent lamp load. Tungsten has a positive temperature coefficient of resistance, so a cold lamp filament has a much lower resistance than it does at operating temperature. The reason one sometimes sees a lower "Tungsten" rating specified for switches and relays is because when an incandescent lamp is turned on it results in a high initial surge current until the filament heats up. John |
Timer for metal halide
(I also don't know what they mean
by '1200 amps R Resistive or 1200 amps Tungsten', but you are nut if you think you're going to put 1200A into anything safe.} Mike meant to type "Watts" rather than "Amps". The "Resistive" rating refers to a constant resistive load. The "Tungsten" rating refers to a (tungsten filament) incandescent lamp load. Tungsten has a positive temperature coefficient of resistance, so a cold lamp filament has a much lower resistance than it does at operating temperature. The reason one sometimes sees a lower "Tungsten" rating specified for switches and relays is because when an incandescent lamp is turned on it results in a high initial surge current until the filament heats up. John |
Timer for metal halide
(I also don't know what they mean
by '1200 amps R Resistive or 1200 amps Tungsten', but you are nut if you think you're going to put 1200A into anything safe.} Mike meant to type "Watts" rather than "Amps". The "Resistive" rating refers to a constant resistive load. The "Tungsten" rating refers to a (tungsten filament) incandescent lamp load. Tungsten has a positive temperature coefficient of resistance, so a cold lamp filament has a much lower resistance than it does at operating temperature. The reason one sometimes sees a lower "Tungsten" rating specified for switches and relays is because when an incandescent lamp is turned on it results in a high initial surge current until the filament heats up. John |
Timer for metal halide
Tungsten has a positive temperature coefficient of resistance, so a cold lamp filament has a much lower resistance than it does at operating temperature. The reason one sometimes sees a lower "Tungsten" rating specified for switches and relays is because when an incandescent lamp is turned on it results in a high initial surge current until the filament heats up. John Actually that is bass ackwards Tungsten filaments have a negative temperature coefficient. Temperature rises conductivity decreases. Back when semiconductors were young a lamp was often used to help prevent thermal runaway in amplifier circuits by placing them in series with the transistor. In any case most lamp timers should be able to handle a 400w metal halide set. Just make sure it is a grounded timer ( 3 prong) Better still would be a grounded timer on a GFCI protected circuit. |
Timer for metal halide
Tungsten has a positive temperature coefficient of resistance, so a cold lamp filament has a much lower resistance than it does at operating temperature. The reason one sometimes sees a lower "Tungsten" rating specified for switches and relays is because when an incandescent lamp is turned on it results in a high initial surge current until the filament heats up. John Actually that is bass ackwards Tungsten filaments have a negative temperature coefficient. Temperature rises conductivity decreases. Back when semiconductors were young a lamp was often used to help prevent thermal runaway in amplifier circuits by placing them in series with the transistor. In any case most lamp timers should be able to handle a 400w metal halide set. Just make sure it is a grounded timer ( 3 prong) Better still would be a grounded timer on a GFCI protected circuit. |
Timer for metal halide
Tungsten has a positive temperature coefficient of resistance, so a cold lamp filament has a much lower resistance than it does at operating temperature. The reason one sometimes sees a lower "Tungsten" rating specified for switches and relays is because when an incandescent lamp is turned on it results in a high initial surge current until the filament heats up. John Actually that is bass ackwards Tungsten filaments have a negative temperature coefficient. Temperature rises conductivity decreases. Back when semiconductors were young a lamp was often used to help prevent thermal runaway in amplifier circuits by placing them in series with the transistor. In any case most lamp timers should be able to handle a 400w metal halide set. Just make sure it is a grounded timer ( 3 prong) Better still would be a grounded timer on a GFCI protected circuit. |
Timer for metal halide
Beecrofter wrote:
Tungsten has a positive temperature coefficient of resistance, so a cold lamp filament has a much lower resistance than it does at operating temperature. The reason one sometimes sees a lower "Tungsten" rating specified for switches and relays is because when an incandescent lamp is turned on it results in a high initial surge current until the filament heats up. John Actually that is bass ackwards Tungsten filaments have a negative temperature coefficient. Temperature rises conductivity decreases. You're both right but you're talking about different things. The resistivity temperature coefficient is positive, which makes the conductivity temperature coefficient negative. At any rate, the inrush current through a tungsten filament is much higher than the operating current. |
Timer for metal halide
Beecrofter wrote:
Tungsten has a positive temperature coefficient of resistance, so a cold lamp filament has a much lower resistance than it does at operating temperature. The reason one sometimes sees a lower "Tungsten" rating specified for switches and relays is because when an incandescent lamp is turned on it results in a high initial surge current until the filament heats up. John Actually that is bass ackwards Tungsten filaments have a negative temperature coefficient. Temperature rises conductivity decreases. You're both right but you're talking about different things. The resistivity temperature coefficient is positive, which makes the conductivity temperature coefficient negative. At any rate, the inrush current through a tungsten filament is much higher than the operating current. |
Timer for metal halide
Beecrofter wrote:
Tungsten has a positive temperature coefficient of resistance, so a cold lamp filament has a much lower resistance than it does at operating temperature. The reason one sometimes sees a lower "Tungsten" rating specified for switches and relays is because when an incandescent lamp is turned on it results in a high initial surge current until the filament heats up. John Actually that is bass ackwards Tungsten filaments have a negative temperature coefficient. Temperature rises conductivity decreases. You're both right but you're talking about different things. The resistivity temperature coefficient is positive, which makes the conductivity temperature coefficient negative. At any rate, the inrush current through a tungsten filament is much higher than the operating current. |
Timer for metal halide
Can anyone provide guidance on how large a timer I need for a 400W
metal halide grow lamp? The vendor suggested a 15 amp grounded outlet, the stated he likes 20 amps ones. However, I recently ran across some nice, grounded 10 amp, outdoor timers ( Intermatic . On the side they list capcaity as 1200 amps R Resistive or 1200 amps Tungsten. I know that Metal halides are different, but do I really need a 15 amp timer or will these 10 amp ones work? Years ago, when I had the money to spend on things like this, I had two 400-watt halides over a large sal****er aquarium (the corals LOVED it). I don't recall the brand, but I bought a timer that was designed for high-draw inductive loads. A couple of years later, I sold off the aquarium, and the timer was still working just fine. steve |
Timer for metal halide
Can anyone provide guidance on how large a timer I need for a 400W
metal halide grow lamp? The vendor suggested a 15 amp grounded outlet, the stated he likes 20 amps ones. However, I recently ran across some nice, grounded 10 amp, outdoor timers ( Intermatic . On the side they list capcaity as 1200 amps R Resistive or 1200 amps Tungsten. I know that Metal halides are different, but do I really need a 15 amp timer or will these 10 amp ones work? Years ago, when I had the money to spend on things like this, I had two 400-watt halides over a large sal****er aquarium (the corals LOVED it). I don't recall the brand, but I bought a timer that was designed for high-draw inductive loads. A couple of years later, I sold off the aquarium, and the timer was still working just fine. steve |
Timer for metal halide
Can anyone provide guidance on how large a timer I need for a 400W
metal halide grow lamp? The vendor suggested a 15 amp grounded outlet, the stated he likes 20 amps ones. However, I recently ran across some nice, grounded 10 amp, outdoor timers ( Intermatic . On the side they list capcaity as 1200 amps R Resistive or 1200 amps Tungsten. I know that Metal halides are different, but do I really need a 15 amp timer or will these 10 amp ones work? Years ago, when I had the money to spend on things like this, I had two 400-watt halides over a large sal****er aquarium (the corals LOVED it). I don't recall the brand, but I bought a timer that was designed for high-draw inductive loads. A couple of years later, I sold off the aquarium, and the timer was still working just fine. steve |
Timer for metal halide
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Timer for metal halide
I enjoyed reading all the responses to this thread. Everybody had some
good input on this one. And the simple answer to your question of a 10 amp timer is:... Yes you can use it. And the long answer is:.... DON'T DO IT!! It will work for a while, but it is a timer bomb! (pun) Might be in a month, might be in 2 years. If you are lucky it will just stop working. If you are unlucky it will fire up and burn like a roman candle! (I have seen digital, analog, and mechanical timers all burn up) Intermatic makes some very good timers, but the one you are talking about is not top quality for what you want it to do. Geir is right to mount on tile. Beecrofter is right, make sure to use a 3 prong timer and if avil a GFCI outlet. Salty is right, I think you will find once a 400 watt MH is up to full inten. it will pull anywhere from 3.6 to about 5 amps (varys from 1 ballist to another , my MHs run 4 to 4.5 for a 400 watt MH fixture) The start up can pull 8 amps or more for a brief period. good rule of thumb is 80% of rating. If you have a 100 amp breaker do not put more than 80 amp load on that circuit.(same applies to the wire as well as the outlet) Remember to be aware that the circuit you are putting this light on may feed other parts of your house. (check it out and total it all up to make sure) Also you may want to think about converting to 220 volt. The ballist should have taps on it for other voltages. 220 volt will save you at least one third of your operating cost of the fixture. Then you need to buy those 220 volt timers for window air conditioners. Or.. invest in 110 volt controled contactors. Your timer will last a lot longer and the contactors do not burn up near as easy as a timer with a heavy load on it. Because of the loads I run in my rooms, I don't evan take chances with outlets. Most all my lights, fans, heaters, and humidifiers are all hard wired into power center enclosed steel boxes that contain the timers and contactors and all hook up points outside of the high humidity areas. In short... I would use the 20 amp timer. HAPPYNESS TO ALL NOOK On 14 Mar 2004 11:43:40 -0800, (Mike) wrote: Can anyone provide guidance on how large a timer I need for a 400W metal halide grow lamp? The vendor suggested a 15 amp grounded outlet, the stated he likes 20 amps ones. However, I recently ran across some nice, grounded 10 amp, outdoor timers ( Intermatic . On the side they list capcaity as 1200 amps R Resistive or 1200 amps Tungsten. I know that Metal halides are different, but do I really need a 15 amp timer or will these 10 amp ones work? Thanks Mike |
Timer for metal halide
I enjoyed reading all the responses to this thread. Everybody had some
good input on this one. And the simple answer to your question of a 10 amp timer is:... Yes you can use it. And the long answer is:.... DON'T DO IT!! It will work for a while, but it is a timer bomb! (pun) Might be in a month, might be in 2 years. If you are lucky it will just stop working. If you are unlucky it will fire up and burn like a roman candle! (I have seen digital, analog, and mechanical timers all burn up) Intermatic makes some very good timers, but the one you are talking about is not top quality for what you want it to do. Geir is right to mount on tile. Beecrofter is right, make sure to use a 3 prong timer and if avil a GFCI outlet. Salty is right, I think you will find once a 400 watt MH is up to full inten. it will pull anywhere from 3.6 to about 5 amps (varys from 1 ballist to another , my MHs run 4 to 4.5 for a 400 watt MH fixture) The start up can pull 8 amps or more for a brief period. good rule of thumb is 80% of rating. If you have a 100 amp breaker do not put more than 80 amp load on that circuit.(same applies to the wire as well as the outlet) Remember to be aware that the circuit you are putting this light on may feed other parts of your house. (check it out and total it all up to make sure) Also you may want to think about converting to 220 volt. The ballist should have taps on it for other voltages. 220 volt will save you at least one third of your operating cost of the fixture. Then you need to buy those 220 volt timers for window air conditioners. Or.. invest in 110 volt controled contactors. Your timer will last a lot longer and the contactors do not burn up near as easy as a timer with a heavy load on it. Because of the loads I run in my rooms, I don't evan take chances with outlets. Most all my lights, fans, heaters, and humidifiers are all hard wired into power center enclosed steel boxes that contain the timers and contactors and all hook up points outside of the high humidity areas. In short... I would use the 20 amp timer. HAPPYNESS TO ALL NOOK On 14 Mar 2004 11:43:40 -0800, (Mike) wrote: Can anyone provide guidance on how large a timer I need for a 400W metal halide grow lamp? The vendor suggested a 15 amp grounded outlet, the stated he likes 20 amps ones. However, I recently ran across some nice, grounded 10 amp, outdoor timers ( Intermatic . On the side they list capcaity as 1200 amps R Resistive or 1200 amps Tungsten. I know that Metal halides are different, but do I really need a 15 amp timer or will these 10 amp ones work? Thanks Mike |
Timer for metal halide
I've used just a simple 2-prong lamp timer. I'm not recommending it,
just telling you what I did. Worked great. Your mileage may vary. Mike wrote: Can anyone provide guidance on how large a timer I need for a 400W metal halide grow lamp? The vendor suggested a 15 amp grounded outlet, the stated he likes 20 amps ones. However, I recently ran across some nice, grounded 10 amp, outdoor timers ( Intermatic . On the side they list capcaity as 1200 amps R Resistive or 1200 amps Tungsten. I know that Metal halides are different, but do I really need a 15 amp timer or will these 10 amp ones work? Thanks Mike |
Timer for metal halide
|
Timer for metal halide
(Mike) wrote in
m: Can anyone provide guidance on how large a timer I need for a 400W metal halide grow lamp? The vendor suggested a 15 amp grounded outlet, the stated he likes 20 amps ones. However, I recently ran across some nice, grounded 10 amp, outdoor timers ( Intermatic . On the side they list capcaity as 1200 amps R Resistive or 1200 amps Tungsten. I know that Metal halides are different, but do I really need a 15 amp timer or will these 10 amp ones work? Thanks Mike A 10 amp timer will work for a while but it isn't designed for an inductive load like a ballast which is basicly a transformer. Every time the timer switches off the ballast acts something like the spark coil in you car causing an arc across the contacts which eventually distroys them. A 20 amp plug in timer will last longer but 95% of plug in timers aren't designed for incuctive loads. I couldn't find a web sight that had a good picture of what you shuld use but I found one on ebay. note this is a dual voltage unit and you'll only need a single 115/120 volt unit. I've run my fluoresent lights (36-40 watt tubes or 1440 watts) for over ten years with no problems. http://cgi.ebay.com/ws/eBayISAPI.dll...ategory=42 89 7 Hope this helps dusty |
Timer for metal halide
Thanks to everyone for all of the feedback.
In short, my take is- Cheap will be O?K for a while- Could be a short while and could be a bad outcome when it goes. Spend more get the better timer. Thanks again. |
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