clavus

I replaced a butt-ugly light in house. The new light has (5) 50 watt halogen bulbs. I added a low-voltage dimmer at the sitch (as per the instructions). Also on this circuit are two other lights - each with a 75 or 100 watt bulb, my ugly-ass kitchen lights (6 florescent tubes), and my microwave.

Now, two of the florescent tubes are humming and dim, and the microwave keeps popping the GFI on its plug (note: the microwave isn't running when it does this. the only energy it is using is to light its clock)

Soooo...as I attempt to sort this all out, I have encountered a question that nobody can answer -

When I turn down the lights in my NEW light via the dimmer I just installed, am I drawing less power, or is the transformer pulling in the same amount of juice, but giving less to the lamps?

Oh, and if anyone can tell me WTF my overall problem is, I'd love to hear that too. I assume my problem is from drawing too much power through one circuit, but the breaker isn't getting thrown, so I dunno.

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clavus

good lord. Why I am playing with electricity, I can't even edit my question without fucking up!

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gar1976

You could try replacing the GFI the 'wave is hooked up to, since it's being thrown whether or not its running.

Dunno about drawing less power on the dimmer switch, though. I just use them for mood lighting

Bossnass

I really don't know for sure, but if pressed I would say that the transformer is drawing the same amount of power regardless of the dimmer setting. I have no real reason to say this but it seems like something I should know, or might have known and have forgotten.

The overall problem could be many things, but the first thing I'd check is the actual circuit 'diagram'. If you managed to wire the new light/switch in series when the originals were in parallel, that could explain your problems. I once worked on a frustrating lighting circuit that went from 'a dim glow' to 'as bright as can be' once I rearranged the pigtails.

If the outlet where the microwave** is plugged in is part of this circuit, then the whole circuit after that junction is protected for a ground fault. Maybe the new light isn't grounded, or more likely the transformer and the GFCI won't get along.

**not to mention that around these parts, as I understand it, microwaves require a dedicated breaker to meet code.

kazoo

First of all, a GFCI operates independently of other devices-it is not an overcurrent device, such as a fuse or breaker.

Dimmers for typical incandescent and halogen lighting devices operate by lowering the supplied voltage-they are variable resistors.

To properly diagnose this, I'd need to open the panel or fuseboard and use an inductive ammeter to see how much current is being drawn. When the circuit ampacity peak is being reached, the GFCI could be tripping due to a poor connection at any point on the circuit.

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b_angelo

Did all these problems start when you replaced the switch? If so and it was me I would take out the dimmer switch and replace it with one like the original. as Kazoo said dimmer switches cannot be used with flourescent lighting. just my 2 cents worth

troit

I need some help... Can you hold onto this wire for me? heheh...

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clavus

Alrighty! Thanks for all the advice. The problem was...a ballast gone bad in the florescent kitchen lighting.

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fhqwhgads

Clavus- You just reminded me of a good story. I went to school with a guy for awhile, and the first time I was at his house I couldn't help but notice the black spots around his ceiling fan. It was one of those things that you just have to ask about, so I did. He tells me that it was a new fan. My reply "Install it yourself, did ya?". He tells me he did, and that he had a little problem with the electricity when he did so. I asked him why he didn't turn off the breaker, and he just looked at me the way my uncle does when you ask him to divide 54 by 13.

wondash

Here's one of the first formulas they teach you in electrical engineering: v=ir
[voltage] = [current] multiplied by [resistance]
Your voltage is constant and your dimmer switch acts as a variable resister, so as you turn the switch you increase or decrease the resistance. Therefore, you increase or decrease the current. So, in answer to your question, dimming the light does draw less current. But the bulb also burns less efficiently and the dimmer switch transfers the unused energy to heat.

james t kirk

Actually, you are all wrong.

A dimmer switch does not work by varying the voltage. (TRUST ME, I have been zapped changing a fixture on a dimmer switch when the light looked like it was off. (It really wasn't off, just turned down so low, the bulb wasn't glowing.))

Dimmer switches work by turning the power on and off really quickly. As you know, AC power in North America operates at 60 hertz (or cycles per second). A dimmer switch works by turning the light on for a variable duration during each cycle.

Dimmers are very very efficient with perhaps a 1% loss only in efficiency.

So to answer your question, yes, dimmers use less power.

But the voltage remains constant at 120 Volts.

Don't believe me, turn the dimmer knob right down till the light bulb isn't even glowing. Put the black wire in your left hand and the white wire in your right hand.

The shock you get will be the same as if it were turned right up.

cheers

james t kirk

Please tell me you aren't an electrical engineer!!!

tropple

If your lights are drawing power as a load running from that GFCI device, then you still have a problem.

You need to consult an electrician. You are working with something that can burn your house down.

Irregardless of whether or not that ballast was bad. There are electrical codes that specifiy how and under what conditions a GFCI may provide power to loads down circuit. If your place burns down becasue of it, I can guarantee you that your homeowner's policy will not pay if you did the work and did not have it inspected by the building inspector.

Not a rant, I just don't want you getting in trouble of having any fires.

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shakran

No, they're not.

That's because you pulled an electrical stupid. You need to understand switches more before you make assumptions like that. A switch only interrupts one leg of the circuit. That means the other leg is still ready to deliver power at the light. When you changed the fixture and touched that active leg, you got zapped because YOU provided a closed circuit with the ground. This is why we tell people to turn the power off at the breaker, not the switch, when they work on a light - the breaker kills BOTH legs.


Half a point for effort. You're right in that NEW dimmers work like this. OLD dimmers worked with a variable resistor that did indeed lower the voltage.



The good ones have around a 2% loss. Cheap ones have more.



Argh! Please learn something about how circuits work before you try to get TFP members killed! They could turn the switch OFF entirely and still get zapped. And if the current travels from their right hand out their left leg they could get seriously injured, especially if they're hot and sweating, standing on a metal ladder, etc. If you don't have GOOD experience with electricity ("duh, i done got shocked once" is NOT good experience) then don't run around telling people what to do with it. Some people are just dumb enough to believe anything they read on the internet and might actually try it.

james t kirk

Shakran,

I have forgotten more about electricity than you will ever know. So don't fucking call me stupid.

Old dimmer switches that use a "variable resistor" (aka rheostat) haven't been on the market for as long as I can remember. You must be pretty old.

I was correct in what I wrote, here's a quick link for you to do a little homework and learn before you go spouting off calling people stupid.

http://www.factsfacts.com/MyHomeRepair/DimmerSwitch.htm

You will note from the sinusoidal wave that the dimmer works by shutting the power off during a certain period of the sine wave. During the period of the wave in which the power is "on" one can still get a 120 Volt shock.

Want more proof, take a volt meter with a very high impedence to circuit with a dimmer switch. The volt meter will read 120 volts regardless of where your dimmer is set.

The voltage is constant.

Here's an even better link, read it too and learn.

http://home.howstuffworks.com/dimmer-switch.htm

james t kirk

You made me laugh with this one. A breaker in a home electrical panel cuts only ONE leg mon ami. That would be the hot wire. FYI, the hot wire is the black wire. The other wire is neutral and has the same electrical potential as the ground - 0. In fact, often times, the neutral wire and the ground wire will be ganged together at some point to ensure that they have the same electrical potential. In the 1920s, the old fuse pairs used to have a fused hot, and a fused neutral to boot. By the 30's and ever since, that has been gone.

I got zapped because I thought the light was off, when really it was just turned down to the point where the light wouldn't glow, but the power was still very much on.




I have never ever seen a dimmer with a rheostat. You are going back before my time.


Read the link I posted above.

1% is in there I believe.

I would not have thought that anyone would have taken me seriously on this.

noblejr

"They could turn the switch OFF entirely and still get zapped."

How? If the switch has cut off the hot wire's current, where do you get current from to get shocked?


"This is why we tell people to turn the power off at the breaker, not the switch, when they work on a light - the breaker kills BOTH legs."

What kind of panel does this at 110V? The only panels I've worked on had the hot wire only on the 110 breakers.

wondash

Not even close.

shakran

Then you should know not to fuck with wiring unless the breaker is OFF. You should damn well know to tell everyone ELSE not to fuck with wiring unless the breaker is OFF.

Don't get pissy with me for trying to stop your shitty advice from getting people killed. No one should EVER tell ANYONE to work on a potentially live circuit for ANY reason.

james t kirk

I was kidding.

clavus

Yo! People mellow out. I fixed the light and I have a real live electrician coming over to put the microwave on its own breaker.

Let's not get our panties in a bunch.

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noblejr

What was wrong? I had an afterthought that maybe a starter in your florescent fixture was fried and the problem had nothing to do with your new lights and switch.

clavus

BING BING! You win the prize! There was a ballast in one of the florescents that went to crap.

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noblejr

YAAAAAAAY! I won! I won! I won!.... YAAAAAAAY!

SaltPork

Way to go, Clavus. You come in here asking for some advice and you end up stirring up trouble....First there was the nakedness and the breaking in to your own house, now this!! When will it all end!?!?!?

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It was like that when I got here....I swear.

noblejr

Whoops! I swear I didn't see this before I posted my "winning" answer.

xepherys

wrkime-

Is Clavus always such a hooligan? Sheesh! ^_^

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