Experienced Electrician! Here to Answer Any and All Growroom Electrical Questions

hibok said:

Powerslide, so you have 40amps to play with for an 80% demand factor.

from here you can pick up a 1 phase 50 amp subpanel, 6/3 wire or if your hardware store has a standalone 240 plug that the same as the configuration of your welding plug comes in 6ft i believe, and two 20 amp breakers
EZPZ ?

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hibok said:

if your talking about bonding all metal devices than the receptacle is already bonding and should be which is returned back to the main panel. so basically he would be matching each wire to maintain continuity to each phase.

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Stevie51 said:

Abiqua said:

Yes the diagram is correct. As you are perhaps well aware of, the resistance of the 1k pot is way too much. We could replace the pot with one of another value, or we could simulate a lower-value pot by placing a resistor in parallel with it, diminishing its maximum obtainable resistance. Placing a 100 ohms 3 watt resistor connected from terminal #1 to terminal #3, will decrease the span of the pot to 91 ohms, but that span will become non-linear.

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Yep, I think resistance of a 12v .215 fan is just about 45 ohms. I can't find lower resistor's with around 100 ohms and handling 500ma...... at least for cheap. 1k was the lowest linear resistor I could find. There were some 500k audio resistors too, non linear.

Is there that much of difference between linear and non-linear @ that low of voltage? I get that the amperage will upsweep as the resistance increases with the in-line resistor [100 ohm] but is it necessary?

Thanks again!

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PhychicTurtle said:

Hi , im in the process of getting and setting up 4 CFL bulbs in a closet , 2 on a top shelf and two on the bottom. I was wondering what the best way to wire them out of the closet it? Also can the 4 of them be wired to the same plug?
Cheers.

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Abiqua said:

Stevie51 said:

Yep, I think resistance of a 12v .215 fan is just about 45 ohms. I can't find lower resistor's with around 100 ohms and handling 500ma...... at least for cheap. 1k was the lowest linear resistor I could find. There were some 500k audio resistors too, non linear.

Is there that much of difference between linear and non-linear @ that low of voltage? I get that the amperage will upsweep as the resistance increases with the in-line resistor [100 ohm] but is it necessary?

Thanks again!

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The most current the fan will draw @ 12 volts is .215 amp. That is less than 3 watts. The purpose of the potentiometer is to add a variable amount of resistance to create a variable decrease of voltage to the fan. The voltage is what control the fan speed. As the voltage drop, so does the amperage drop. You do realize that too much resistance can cause too much of a voltage drop and stall the fan. Ideally it would be nice to have a potentiometer that is linear and have just the right amount resistance to utilize the full sweep of the potentiometer knob without stalling the fan, but I understand that isn't an option for you now. That's the reason I suggested adding a 3 watts resistor (available from Radio Shack for $1.89) in parallel across the potentiometer. To calculate resistance in parallel use the formula: (R1 x R2) divided by (R1 + R2). Because the resistor has a fix value, and the potentiometer has variable value through its span, the resulting resistance will become non-linear. As I have no experience doing this project, and thus don't know the voltage drop you are trying to achieve, the 100 ohms resistor I had suggested may not be the ideal resistor in ohms. I do hope you realize that what we are doing is "improvising". The decision rest with you as to what is necessary.

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Stevie51 said:

Abiqua said:

The most current the fan will draw @ 12 volts is .215 amp. That is less than 3 watts. The purpose of the potentiometer is to add a variable amount of resistance to create a variable decrease of voltage to the fan. The voltage is what control the fan speed. As the voltage drop, so does the amperage drop. You do realize that too much resistance can cause too much of a voltage drop and stall the fan. Ideally it would be nice to have a potentiometer that is linear and have just the right amount resistance to utilize the full sweep of the potentiometer knob without stalling the fan, but I understand that isn't an option for you now. That's the reason I suggested adding a 3 watts resistor (available from Radio Shack for $1.89) in parallel across the potentiometer. To calculate resistance in parallel use the formula: (R1 x R2) divided by (R1 + R2). Because the resistor has a fix value, and the potentiometer has variable value through its span, the resulting resistance will become non-linear. As I have no experience doing this project, and thus don't know the voltage drop you are trying to achieve, the 100 ohms resistor I had suggested may not be the ideal resistor in ohms. I do hope you realize that what we are doing is "improvising". The decision rest with you as to what is necessary.

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Right now the 1k is fine, I just wanted to slow down the interior fan to about 9-10v's, while keeping the exhaust @ max. The sweep range of the 1k pot actually is right in the zone. Allows me to turn it down slightly and I almost get a full sweep before it cut's out, so no worries, here, I actually think this fits in exactly where I want it.

However, I will certainly brush up on what you have put down, great info!!!!!!!

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SnapsProvolone said:

Do a search for medium base light bulb stringer.

Get the style with an integrated breaker.

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SnapsProvolone said:

Sure if you dont mind changing a fuse instead of resetting a breaker. should only become an issue if the bulbs installed were drawing too much current. Key is fuse amperage is not to exceed the ampacity of the wire guage used. And fuse the hot leg not the neutral. Nice thing about a stringer is it allows someone to have something ul/etl approved.

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SnapsProvolone said:

And fuse the hot leg not the neutral. Nice thing about a stringer is it allows someone to have something ul/etl approved.

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Vansterdam said:

Can someone explain the Ferrite Clamps to block or contain RFI noise. Do i just need to clamp 1 unit to the cord leading from the ballast to the light? What size clamp do I need for a 16 gauge cord?

I had a visit from the cable guy a couple of years ago, I'm not looking forward to another knock on the door...

Cheers.

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SnapsProvolone said:

Its a ferrite RFI Supression Choke. Available at Radio Shack. Put one on the ballast end of the feed to the lamp.

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