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Author Topic: 200 amps at 110 volts - what wire gauge is needed?  (Read 9955 times)
WA2GO
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Posts: 6




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« on: October 03, 2012, 09:12:42 PM »

This totally cracks me up - a genius chicken bander is selling an amplifier on ebay and calling it a "200 amp 110V power supply".

http://www.ebay.com/itm/FATBOY-200-Amp-Power-Supply-110V-/261100707939

A cable that could carry that current is probably the size of my arm.

I can't understand why ebay flat out refuses to remove illegal amplifier listings.  I have reported easily over 100 of them, and never have they removed a single one.
Now that 10m is open a lot, it really torques me hearing all the AM and SSB pollution in our CW band.
I have recurring fantasies of finding one of these guys, and having a ninja put a 1/2" finishing nail through his coax at 3 AM...
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N4CR
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Posts: 1668




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« Reply #1 on: October 03, 2012, 10:20:20 PM »

Voltage has nothing to do with wire gauge. Might have some bearing on the insulation, though...

#0 wire (0.325 inch diameter) in free air will carry 245 amps.

#000 wire (0.410 inch diameter) in conduit will carry 200 amps.

These figures are at a max ambient of 60°C.

Way to go. Nice call.
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73 de N4CR, Phil

We are Coulomb of Borg. Resistance is futile. Voltage, on the other hand, has potential.
AH6RR
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Posts: 803




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« Reply #2 on: October 04, 2012, 12:34:37 AM »

I hate to say it but I think he means it is a 13.8VDC 200 amp power supply that works on 110V so he can run his Leaner amplyflyer that has a 1600W out put into a Dossy Meter (= 400W on a Bird)
Diaz quatro me amigo.

LOL

AH6RR
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AA4PB
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Posts: 12854




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« Reply #3 on: October 04, 2012, 05:38:31 AM »

It's a power supply. To deliver 13.8VDC at 200A with 120VAC input is going to require a dedicated 30A branch circuit however.
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KE3WD
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Posts: 5689




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« Reply #4 on: October 04, 2012, 09:13:28 AM »

Yetch, 13.8V rail, multiple bipolar rf transistors, this is a veritable RECIPE for distortion and splatter. 

Of course.


73
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K8AXW
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Posts: 3860




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« Reply #5 on: October 04, 2012, 09:24:38 AM »

You guys are now walking around in a world where logic, understanding, technical ability is not only unnecessary but cannot be considered. 

Enjoying a good laugh like this is like taking a drug that gives you a high but then you experience a sharp low when it wears off. 
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KD0REQ
Member

Posts: 950




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« Reply #6 on: October 04, 2012, 10:45:37 AM »

it's a bet that you don't have to tune that chucklehead in, you can get his splatter on the TV, the microwave display panel, the electric toothbrush, and that old filling you are going to get fixed next January when the next insurance period kicks in.
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W8JI
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Posts: 9296


WWW

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« Reply #7 on: October 04, 2012, 03:53:58 PM »

The thing on eBay linked here really is a power supply, not an amplifier. It is a big heavy high current power supply made by a company that also builds and sells CB amplifiers. Fat Boy sells amps and power supplies and other junk.

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KB1GTX
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Posts: 460




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« Reply #8 on: October 04, 2012, 04:15:29 PM »

You'll find that power supply is  unregulated  and no loads around 21 volts for running their 27mhz square wave generators.
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W8JI
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Posts: 9296


WWW

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« Reply #9 on: October 04, 2012, 05:41:48 PM »

Crap, I was gonna run radidio on it
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K4RVN
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Posts: 775




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« Reply #10 on: October 04, 2012, 06:27:16 PM »

To WA2GO
John I agree with you but can't answer your question. In general the higher the voltage the smaller wire gage is required for a given number of amps. That's why the power company has high voltages in their transmission lines to reduce the wire size required. Voltage has everything to do with ampacity for a given wire size. Normally 110 volts would use
14 gage wire to carry 15 amps but the length would account also due to the resistance. This is all plugged in to the various AC and DC formulas. A short wire length would have less resistance thus a smaller wire for 200 amps than one a 100ft long for the same voltage drop. Point you made is correct that it could be a larger wire at 110 volts than one normally would use.


Frank
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N4CR
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Posts: 1668




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« Reply #11 on: October 04, 2012, 08:36:40 PM »

Voltage has everything to do with ampacity for a given wire size.

No, it doesn't. No matter the voltage, amperage is a measurement of how many electrons passed through a cross section of the wire. It's a measure of current, not voltage.

20 amps is 20 amps where it's driven by 1 volt or a million, and it takes the same gauge wire to carry it.

The insulation requirements, however, would be massively different.

http://en.wikipedia.org/wiki/Ampacity

Ampacity has many factors, but voltage isn't one of them.
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73 de N4CR, Phil

We are Coulomb of Borg. Resistance is futile. Voltage, on the other hand, has potential.
K7KBN
Member

Posts: 2805




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« Reply #12 on: October 04, 2012, 09:09:02 PM »

To WA2GO
John I agree with you but can't answer your question. In general the higher the voltage the smaller wire gage is required for a given number of amps.
Frank

Change the next word from "amps" to "watts" and you'll be a lot closer - assuming that current is a constant.
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73
Pat K7KBN
CWO4 USNR Ret.
N4CR
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Posts: 1668




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« Reply #13 on: October 04, 2012, 10:07:16 PM »

To WA2GO
John I agree with you but can't answer your question. In general the higher the voltage the smaller wire gage is required for a given number of amps.
Frank

Change the next word from "amps" to "watts" and you'll be a lot closer - assuming that current is a constant.

Yes, but now you're talking about a unit of work. Neither amps or volts describe a unit of work.
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73 de N4CR, Phil

We are Coulomb of Borg. Resistance is futile. Voltage, on the other hand, has potential.
K7KBN
Member

Posts: 2805




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« Reply #14 on: October 05, 2012, 07:08:05 AM »

To WA2GO
John I agree with you but can't answer your question. In general the higher the voltage the smaller wire gage is required for a given number of amps.
Frank

Change the next word from "amps" to "watts" and you'll be a lot closer - assuming that current is a constant.

Yes, but now you're talking about a unit of work. Neither amps or volts describe a unit of work.

And neither watts nor volts describes a unit of current.
Logged

73
Pat K7KBN
CWO4 USNR Ret.
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