091202-1000 EST
I have no idea what the question is in the original post.
cadpoint:
PhaseShift's statement was correct. If you consider a specific heater its resistance can be considered approximately constant over a fairly large voltage range. My heater that I use as a test load has a room temperature resistance of 8.6 ohms (this means no voltage applied and 68 deg F). At 118 V and the same ambient room temperature its resistance is 10.6 ohms. In turn I approximate this as a 12 A load at 120 V. More accurately it is 11.32 A.
If you have a 10,000 W heater at 240 V, then at its steady state on temperature its resistance is 5.76 ohms. As a first estimate its current at 120 V will be 20.8 A, just 1/2 of its current at 240 V. And the power dissipated would be 1/4 that at 240. However, the resistance will go up slightly at 120 V because the wire in the heater is cooler. So at 120 V current and power will be somewhat less than predicted by assuming a constant resistance.
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THANKS GAR:
You are right, I missed the response of the EXACT question, "again"!
I thought I was talking about P/V= I
I didn't talk about or address "R" or a stead state. I surely didn't have test subjects or data available to pull in gee I just did some math.
If my math is incorrect please say so, my post can be taken out if so
inept, one more won't matter... go ahead and hit the panic "!" and qualify it!
I did say that the numbers where smaller, as to what is more real or realistic.
In thinking about again these values of the available "R" or available stead state just aren't worried about. What a person on the line usually only has is available wattage required by the item and available voltage that can be used, I hope they figure it out.