AC compressor

You don't know how to use a library? I don't need to give you the science, I have directly observed the phenomenon. Direct observation makes up most science. I did find a document online that has some equations if that will help you understand but if you know anything about electricity, you can visualize that a length of wire has a magnetic field when energized. Take a look at page 3 of the PDF:

e:

A piece of 10 guage wire is not going to heat up fast enough to move at a rate you could observe with the naked eye at these currents.

e:

I know something about electricity. I know it takes a great very deal of current to make a strong magnetic field in a straight wire. Possible in a commercial setting with high pulsed current, yes. In a home ac compressor, I doubt it. Go ahead, hold your ferrous screwdriver blade near the 10 guage wire with the compressor running. Feel any pull?

High current --> wires heat --> heat causes expansion --> expansion causes movement (not exactly "rattle" perhaps, but insulation sliding against insulation could probably approximate a squeak)

Am I missing something? What's so hard to understand?

I'm reminded of a joke, I'm about to make up. Bill Gates, a pollack, an engineer, and a meterologist are sitting in a room. The one of them asks if it's raining. Bill Gates whips out a PDA, connects to the internet, and looks at a radar map. Says it's not raining. The engineer takes a large piece of plastic. Builds a frame, balance point, and connects the other end of the support to a reverse reading mass scale. He extends this out the window. The liner acceleration of gravitational impulses of descending precipitation are negligible. So, he concludes it is not raining. The meterologist calls the NOAA phone number, listens through the recorded message. And concludes it is not raining. The pollack opens the door, steps outside, and comes back in wet. He brings back in the engineer's device (which was under the eaves). Reports that it is raining. The other three gang up and pound the stuffing out of the pollack, while calling him a liar.

Yeah, I'm sure the wires wiggle. Heck, it only makes sense.

The stormin MORON.. had this to say.

Did you mean? Polock? Which is a racist word for our fine Polish countrymen...

You.....! My friend, are a pure bred racist

How do you get off calling yourself a MORMON? HUH? Do all Mormons use racial epitaphs, like you?

First, you haven't quantified the surge current.

Second, he didn't see it, he heard it. Things that appear still can make noise -- consider a piezo speaker.

Third, the other poster has offered an alternative explanation.

No he was talking about a fish -- the pollock fish.

How's that webtv working out for you

Did you join a perfect church? If so, it's not perfect anymore.

I've met some hot Mormon females. It was Shock -n-Awe.

You obviously didn't understand, the wire movement happens when the compressor starts, not continuously. The compressor starts, you can hear the breaker buzz and the wires in a conduit jump, rattle for a split second, not during normal run operation. GEEZ!

TDD

The inductive kick of a high current motor/compressor start can cause wire inside a metal conduit to make noise. I've heard the telltale racket a million times in many different settings. It sounds a lot like somebody shaking a metal fish tape inside an empty conduit.

TDD

A walking, talking fish is too valuable to beat up.

TDD

Yea, #12 is too small for a three ton unit.

TDD

I think they want 10 gage, starting at 2 1/2 tons.

The nameplate on the condensing unit gives the minimum circuit rating. Wire and install a circuit breaker to match. The circuit breaker is not meant to protect the equipment, it's for protecting the wiring.

TDD

Thats it, shaking a fishtape in conduit, and thats how I knew it was kicking on since 94, I wonder how long it will take to shake off some insulation.

I wonder what will happen when one of the wire dancing deniers first hears that sound. Hummm, must be a big rat in here? 8-)

It's probably THHN insulated wire which has a clear Nylon outer jacket that is slippery making it easy to pull and chemical resistant. The slick jacket may keep it from abrading unless it's on a sharp metal edge somewhere.

TDD

You picked a good moniker.

Oooooo the wire dancing denier is trying to insult me. Dufas is a proper name you less-on. *snicker*

TDD

So now if the wire is smaller it dances more? What do you figure, the electrons are closer together?