191204-2005 EST
mike4326:
This thread is getting old, and you have not reported back with what you may have done or found.
I would not approach searching for the point of the problem like the average electrician seems to suggest. Usually they want to start pulling stuff apart. Sometimes that may be necessary, but I would prefer that you make measurements. Then you do not disturb items that are not the problem.
We can assume that three wires (conductors) go to the outlets. These would be hot, grounded current carrying (call it neutral even though it may not be a neutral), and EGC. The highest probability is that only one conductor of these three is the problem. The lowest probability is that all three conductors are open circuits. Thus, my expectation is at least one conductor is conductive with a low voltage drop at a current level of 10 A.
For testing I suggest you have a 3 conductor extension cord starting at a known good outlet, and extending to your problem area, a 1500 W space heater, a high impedance DVM (10 megohms input) that resolves at least 1 mV, misc wires, and plugs, and possibly a Kill-A-Watt EZ.
To start use the extension cord EGC as your voltage reference point. With no load on the problem outlets measure the voltage on each each of the three wires relative to extension cord EGC, record the values. Next plug the heater into one of the outlets, and remeasure the said three voltages. These measurements should already tell you something.
Suppose all were not more than a millivolt or so. Would mean the hot is not hot, and there is a very high impedance in the hot wire, a really open circuit. Without the heater load if you are in the millivolt range to the outlet hot, then it has to be very open.
All the other combination of results you could obtain would direct you to the problem, if you understand electrical circuit theory.
Some experimental results on two outlets of a working circuit with the outlet spacing being 5 ft, and an assumed wire length of 7 ft of #12 copper.
#12 copper wire is nominally 0.001588 ohms per ft at 20 C. Thus, I can assume the resistance of my 7 ft wire is 0.0111 ohms. However, when loaded with 12.2 A the wire temperature will be somewhat greater than 20 C. Also there will be some differences in actual wire diameter. At 12.2 A and 0.0111 the calculated voltage drop is 0.135 V. The 7 ft is a guess, and I don't know the wire temperature. Measured results --- hot 0.151 V, and neutral 0.154 V. Close to the calculated value.
Suppose we found that loading the hot slot of one of your nonworking outlets with 12.2 A to the extension cord neutral produced a voltage from another hot slot to the extension cord EGC of the expected nominal 120 V, then at least to the two selected hot slots we can assume the hot circuit is probably OK. From voltage measurements to the various outlets you can determine which is the first in the series.
If the above looks good, then you test the neutral in the same way except now you use the extension cord hot as your power source.
If you do not understand this, then ask questions.
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