15A vs. 20A - Page 2

Need help with equipment usage or want to share your latest discovery?

#11: Post by CoffeeBuzz »

You quoted my post before I made the final edit (:roll:), where I added the part about the distance from the mains. A house with less than 15' of copper between the circuit breaker box and machine (like mine) will have ~1/6 the IR drop compared to one where the machine is 100' away.

I realize that...the "120V" example....was just that...an example. But in any case, the voltage drop across the wire will be the same regardless....same current, same resistance in the wire. Just a different reference voltage to start/end with.

CoffeeBuzz wrote:
Also, the voltage drop when under load will vary tremendously, depending on the wiring in the house.
But PigSnack has clarified his question, so I guess it is a moot point...


#12: Post by Grant »

mhoy wrote:I'd have to say it's a plecebo affect....
hehe....let's try an experiment regarding this "placebo" effect, shall we? Take a 20W light bulb, turn it on, and place your hand tightly around it. (Also remember...some of the energy is being converted as light, not heat).

As soon as your hand heals....type us out the results of the experiment :twisted:

But I agree, small percentage overall...but it does make a difference with roasters etc, considering the purchase of variacs etc. And at 15A, you lose more (around 44W)...as current increase, so does the power loss.


#13: Post by ntwkgestapo »

OK, Time to chime in on this.

FIRST: Voltage is "potential". Think of a small creek with a 5 foot dam blocking it's bed. That 5 foot dam provides a 5 foot "Potential" (this is your 120 volt potential). Then think of a pipe at the bottom of the dam that allows the water to flow out of the dam. If that pipe is 6 inches in diameter then water will flow thru the pipe with the stored energy of the 5 feet of water pushing down. You'll be able to utilize the water that flows thru this pipe to do work (this is your "amperage"). If you increase the height of the dam to 10 feet you get a greater potential, but the 6 inch pipe still limits your "amperage" to some fixed value... more potential energy, but the flow of the energy is still limited by the 6 inch pipe. Increase the pipe size to 1 foot and you've quadrupled the available amperage (the circular area has increased almost 4 times, so you get just under 4 times the volume of water flowing out of the pipe).

Most espresso machines made in Europe are running on 220volt circuits and the wire size is smaller (as the potential is doubled, roughly, from the US so the current needed is significantly smaller to achieve the same wattage). The dam is higher so the pipe doesn't need to be as large to achieve the same total work capabilities (total wattage is the same, lets say 1500 watts). That's why Chris @ Chris Coffee and Jim @ 1st-Line try to get the manufacturers to increase the wire size used internally... Wattage may be the same, but the potential voltage is smaller (110-120 volts) so the current flow has to be greater to achieve the same work produced. Most European systems will use 14 or even 16 SWG (standard wire gauge) wire because the voltage is not limited by the wire size (it's limited by the insulating capabilities of the wire and the spacing between the wires). BUT the CURRENT carrying capabilities of the wire are limited by their size or gauge. To continue the dam example from above, in Europe the dams are higher, they're the 10 foot ones but the pipes are smaller. They're the 6 inch pipes. In the US the dams are not as high, they're the 5 foot ones so the pipes have to be larger, let's say 8.5 inches to provide for the same work produced!

Hope this helps!

Oh, and don't worry about the "spacing between the wires"... ANY UL or ETL approved wire used in 120 volt or 220 volt systems will have insulation rated @ 600 volts minimum. Spacing between the conductors comes into play when you're working with much higher voltages. The wires on the high voltage transmission lines used to distribute power around the US and Europe DO have to be concerned with the spacing! When you're talking about 200 kilovolts or more, THEN you really start to worry about spacing, even down to worrying about things like birds or animals passing IN BETWEEN the conductors (and you start worrying about humidity, etc.)...

EDIT: I mention Chris and Jim ONLY as examples of people who try to "do the right thing". I'm NOT trying to say, or even imply, that other importers don't!
Steve C.
I'm having an out of coffee experience!
LMWDP # 164


#14: Post by gscace »

PigSnack wrote:I've seen a couple posts where people note increased performance from a machine that is wired for 20A vs. 15A. I don't understand this as the heating elements are the same wattage in both configurations and should draw equal current. Is it a root-mean-square / Volt Amp f(x) thingy <grin>? Isn't the 20A service more about having a circuit in your kitchen with higher capacity?
Which machine, specifically? If you are talking about the La Spaz Vivaldi, then Mathew Brinski gave the relevant answer for your question.