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Originally Posted by Eaglesfan27
So, the electrician checked the house out today and he said the house is wired impeccably. He says it has "arc-fault breakers" throughout the house and he feels the house is very safe and ahead of code. He says even with everything turned on upstairs it is only drawing 11.7 amps and the circuit is wired to handle at least 15. He says all of the wiring looks flawless and he cannot find any problems in the house. He did have a multimeter but did not have or use a megger today. I'm not sure if I should be reassured or concerned that he was "stumped." He thinks the one lamp we have which has been flickering, may be producing some kind of feedback into the circuit and causing these two rare events, but he said "that would be very unusual." On the plus side, since he was a friend of Mrs. E's, he was very reasonably priced for a 2 hour service call (particularly considering he had to drive a distance as well.)
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Sounds like it is a recent build or updated electrically which is good.
The amp statement is a bit baffling, assuming it is on a 15 AMP breaker a circuit is not supposed to be loaded more than 80% (12A)for any real period of time, which you are below but not by a lot. An 11 A circuit that didnt have a major appliance on it would be very rare in my homes. We typically work in higher end homes and as such use larger panels to accomodate more "diversity" (has an electrical meaning slightly different than the standard one) and load splitting.
Ok, that babble aside.
Here is what I fear maybe happening and why I specifically mentioned a megger.
*NOTE THIS IS NOT A DIAGNOSIS, JUST A HUNCH*
It is possible that inside the walls leading to the upstairs area or in one of thee effected rooms the wire is pinched or otherwise has had its integrity damaged. (Most likely cause would be a support staple being hammered in too tight, one of my goliaths cost me $800 yesterday for this very reason).
Electricity will ALWAYS follow the path of least resistance, so during normal operation that is probably right on down the copper conductor and everything works well. Heat build up in an electrical circuit is an additive event and with a constant load the temperature of the conductors will slowly rise over time. As temp rises metal expands, nothing new here. Also as temp rises the insulation value of the jacket degrades, (for this reason every wire carries a temp rating, above this rating you can actually be shocked touching an insulated wire) After a while the constant load builds up heat, the wire expands slightly and an easier flow path is developed (through that staple into the wooden studs of the house for example).
This is where the megger comes in, in my opinion.
The whole purpose of a megger is to induce current into a circuit to see if the integrity of the conductors breaks down at a controlled and known value. This would allow you to definitively tell if it is a wiring issue.
All that said, a much more likely scenario is the breaker itself is actually crapping our on you, especially if all this is on on circuit. What scared me initially was that you had (I thought) multiple circuits fading out at the same time. Since wires are routed in bundles most often, it is much more likely that 2 or 3 wires got pinched at a single point (even the holes where the wires go through the studs is a possible and frequent location) than 2 or 3 breakers failing simultaneously. If it is all on one breaker, this goes out the window.
Now onto another question said electrician is he a residential, commercial or industrial guy? If their ad says all three, they are either A) very small B) Resi and want to be bigger C) lieing...
The reason I ask is while most start in resi and move out, many guys now have lived in the commercial world all their lives, and while electron flow is the same, that is about it. Commercial 3 phase has a true neutral to balance the uneven load, plus the conductors are almost always encased in a metal conduit and there is very little instance of conductor damage. In a house the cable is just double jacketed (most have seen this but it is 2 jacketed cables and a 3rd unjacketed cable all encased inside an outer jacket) Conductor damage issues are much more common in resi applications.