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Weird Home Electricity

Weird Home Electricity

Weird Home Electricity

(OP)
I've got a circuit in my home that is incomprehensible (to me at least). From a new 15A breaker (installed a couple of months ago), the wire goes to a plug in the hall bathroom, to a wall plug in the master bathroom, then to a GFCI plug next to my wife's sink, and finally to a plug next to my sink. Four duplex wall outlets. Two of the holes have night lights in them. The electrician verified that those four plugs were all that was on that breaker (no Dr. Evil heat sinks or anything).

Two to three times a year my wife yells at me that her hair dryer doesn't work. Before we replaced the breaker, I would go to the breaker box and turn it from tripped to off, and back to on. Circuit still dead. Wait about an hour and turn the breaker off and back on and all the plugs are live.

I thought there was something in the breaker that was causing the problem and in spite of the electrician telling me that there is no way it was bad, I had him replace it. Today it did it again except the breaker was not tripped. Neither was the GFCI (which I replaced before I had the breaker replaced). I opened the panel and the breaker shows 122V to common when closed and zero when open. I finally gave up and went to do other stuff. About an hour later I cycled the breaker and all the circuits were live.

It acts like it has to cool off for a while before it will start working again. Anyone have any ideas?

David Simpson, PE
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. —Galileo Galilei, Italian Physicist

RE: Weird Home Electricity

My guesses:
1) breaker tripping with no reciplticle loading do to short?
2) heat from short is opening a break in the feed wire?

RE: Weird Home Electricity

There is a thermal cut-off switch in hair dryers that will reset when it cools down. Perhaps you are making the mistake of using the hair dryer as the power-on indicator for the circuit. Hair dryers will trip-off due to the inlet screens getting partly plugged with hair and lint.

Circuit breakers are also thermal devices and need to cool to reset. It should not take that long though. Check the temperature of the breaker when it trips. A poor connection to the bus bar will cause heating. Heat from an adjacent breaker could also be the cause. GFCI problems can be difficult to find. The trip indicators sometimes do not indicate. Use the test and reset buttons to make sure the breaker is working properly.

RE: Weird Home Electricity

Probably a wiring problem. A recording meter would be good tool, see what the current was doing prior to the trip and when it started doing it. An ammeter with a max capture that you could leave on the circuit for awhile would be useful. Even just a regular old ammeter could give some clues - what's the current in the circuit with just the two night lights?

If closing the breaker put 122V to neutral on the load side, the breakers is closed and good. Your hour is waiting for the wiring trouble to cool off and reestablish contact. What ever your problem is, there are far worse ways for it to manifest itself than the repeated tripping of a breaker, like the breaker not tripping. Sounds like a nontrivial problem that should be addressed as soon as practicable.

RE: Weird Home Electricity

(OP)
The two night lights go off as well as the dryer not working, I'm not using the hair dryer as an indicator of a live circuit.

I happens every 3-4 months with no pattern that I can see. Not sure that a datalogger is really practical, but I'll look into it. Where would you put it?

David Simpson, PE
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. —Galileo Galilei, Italian Physicist

RE: Weird Home Electricity

Any chance of a nail or drywall screw partially (and intermittently) puncturing the cable somewhere along the run?

The history and age of the house, along with any renovations, would be an indicator of likelihood.

RE: Weird Home Electricity

If the bus bar extension had a bad connection to the bus or to the original breaker there will be heat damage. That will result in the breaker tripping on the thermal trip. It will have to cool down before resetting.
I would pull the breaker and check for heat damage on the bus and/or the bus extension.
I had to do a rebuild job on an old panel once because of heat corrosion. A couple of breakers were tripping at much less than their rated current due to the heat from bad connections to the bus bars.

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: Weird Home Electricity

(OP)
When we replaced the breaker we checked carefully for any signs of heating and couldn't find any (I had the breaker on my desk for several months and had everyone who came to my office that had any electrical expertise look at it and no one could find signs of heating).

The house is about 20 years old, and there hasn't been any major renovation in 6 years.

Since the wiring goes from the breaker box to a plug in the hall bathroom (about 15 ft) and then to the master bath (another 60 ft), I'm wondering if that receptacle might be the problem (it seems that if the problem was after the hall bath, the plug in the hall bath would still be live). Does that make sense? I think I'll replace it and see if the problem goes away.

David Simpson, PE
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. —Galileo Galilei, Italian Physicist

RE: Weird Home Electricity

Do you lose power at random times, or only when the hair drier is in use??

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: Weird Home Electricity

(OP)
That is a really good question that I haven't thought to ask. I just did and she says that when the circuit is going to be dead she plugs in the dryer and it is already dead (i.e., the dryer is the indicator of a fault, not the initiator). She says that sometimes she notices the nightlight is off as she's plugging it in.

So, we know that the fault is sometime is a 24 hour period (she has never had the circuit trip while drying her hair, if it starts it lets her finish). Then I open the breaker manually for about an hour and then close it and the circuit is live for a few months. Let's say that the circuit was dead for 22 hours before it was discovered, what does actually opening the breaker for 1 hour or so change?

David Simpson, PE
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. —Galileo Galilei, Italian Physicist

RE: Weird Home Electricity

...nothing, if it was really dead.

what if you didn't do anything with the breaker, would it come back on anyway?

RE: Weird Home Electricity

Please confirm:
1. The breaker is actually tripped, not in the on position when the problem is first noted.
2. Immediately after resetting the breaker you have 120V +/- from the breaker lug to neutral.

I think I've read both of those. If both are true the problem is entirely in the wiring beyond that breaker lug.

RE: Weird Home Electricity

is it possible that the neutral is trying to go through some alternate path which is intermittently connected?

Is the GFCI wired correctly? Does the problem persist if the GFCI is replaced?

RE: Weird Home Electricity

I'm thinking intermitted wiring low level short circuit or switched wiring; I also suspect the GFCI installation. I found a weird one that had the power in and load wires reversed.

RE: Weird Home Electricity

(OP)
The old breaker always tripped when this happened. The new breaker did not (this is the first time we've had this problem with the new breaker). Before I did anything else, I took the cover off the panel and checked the voltage across the breaker, 122V. I opened the breaker and voltage was zero. Closed the breaker and the voltage was 122V, and the plugs were still dead.

Ivymike, one time (with the old breaker), my wife discovered the problem after I left for work. We just left it till I got home. When I got home I found that the breaker was tripped. I reset it and the power was not restored. I opened the breaker and went to do some other things. Came back about 3 hours later and closed the breaker and everything worked fine for several months.

I'm not sure I understand circuits very well, but when I hit the test button on the GFCI (number 3 in the chain), then it is dead and the plug by my sink (number 4) is dead, but Number 1 and 2 are still live. So I'm not sure how physically a fault in the GFCI or bad wiring on the GFCI kills all 4 plugs with the breaker still closed. Based on my experience with the way this GFCI does in fact work (TEST on #3 kills power to #4, but not #1 and #2), it seems like the problem must be in plug #1 or the first 15 ft of wire.

Am I missing something in my tentative understanding of electricity?

David Simpson, PE
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. —Galileo Galilei, Italian Physicist

RE: Weird Home Electricity

This is along the lines of ivymike's comment re "neutral intermediately connected".

If the circuit is "dead" you need to check if anything else in the house that is normally switched on / in use (when the suspect circuit is operative) is in use at the time the circuit is dead, (clear I hope - read it 3 times and now confused- must be old age creeping up) - possibly a problem somewhere with active or neutral continuity.
I had a problem in my own home which after 6 months investigation was finally tracked down to the community street lights switching on in the evening, there was a low voltage feed coming in thru' the neutral - turns out it is of no consequence just a frustrating exercise locating it.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

RE: Weird Home Electricity

I would carefully inspect the wiring in that first receptacle, maybe something is loose or poorly done.

RE: Weird Home Electricity

I have an "outlet tester" that I got from the hardware store. There's a model for GFCI and one for non-GFCI protected receptacles.
Basically a 3-pronged plug with a row of LED's that light up in a variety of combinations, depending on the status of the wiring to the receptacle.
I found mine very handy after moving into my current house. All kinds of slap-dash wiring in it.

STF

RE: Weird Home Electricity

I've had bad outlets before, especially if it was wired with the push-in connector, rather than the screw connector. They can give intermittant failures. I hate those push-in connections - a time saver for the electrician, but they seem to not make reliable contact. I'd pull the outlets and wire to the screw terminals.

RE: Weird Home Electricity

My brother-in-law electrician, who has 35+ years of experience [interestingly, with my first keystroke that came out as 35+ tears of experience - maybe some truth in there?] has told me he could not begin to count how many times "speed-wiring" has proven to be problematic when he responds to trouble calls.

When we recently undertook a major home renovation we specified that all wiring was to be copper only, and terminated under screw terminals, added cost notwithstanding.

No issues yet.

CR

"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]

RE: Weird Home Electricity

Had a similar problem in my home, turned out the neutral loosened at the bus bar in the breaker box and would intermittently lose contact. Had a devil of a time figuring it out, but a tweak on the screw solved the problem. It's been good for several years now.

RE: Weird Home Electricity

The problem is not the breaker. But, I would be concerned that the breaker is tripping on a circuit with apparently little load. That is indicating that something is shorting and the shorting and possible arcing could eventually lead to a fire.

Is the electrician 100% certain those are the only 4 loads? This needs to be verified 100%. Once the complete circuit is known then I'd start at the breaker panel and work towards the far end checking the circuit for issues. If a problem can't be found in the breaker or outlet boxes then I'd consider hi-pot or megger testing the wiring to try and find a problem in the walls.

RE: Weird Home Electricity

(OP)
The problem definitely was not the breaker, but the old breaker had its own problem (tripped on the bench at 5A instead of allowing 15A to pass). The new breaker did not trip contemporaneously with the latest power outage. I don't know about 100%, but the electrician was pretty certain that there were only 4 plugs on the circuit. When we re-did the master bath a few years ago he wired #2, #3, and #4 (they moved locations in the remodel), and when he checked at the time he was confident that the only thing left on the circuit was #1.

I will check all the neutral lugs in the box. Intuitively, I can't see how this could be the issue, but my intuition is pretty weak in this stuff.

David Simpson, PE
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. —Galileo Galilei, Italian Physicist

RE: Weird Home Electricity

Quote (SparWeb)


I have an "outlet tester" that I got from the hardware store. There's a model for GFCI and one for non-GFCI protected receptacles.
Basically a 3-pronged plug with a row of LED's that light up in a variety of combinations, depending on the status of the wiring to the receptacle.
I found mine very handy after moving into my current house. All kinds of slap-dash wiring in it.

My home inspector had one of those. About half of my wall plugs were wired incorrectly. I bought a tester, and I replaced all of my switches and outlets, and I made sure they were wired correctly.

--
JHG

RE: Weird Home Electricity

This may not be anything, but humor me, and answer me if the breaker that was removed was a GFCI breaker, or anything special like an AFI breaker?
The 5 amp trip just sounds strange.

I once had a breaker that tripped now and then on my dryer, and it would only trip the heater, and not the motor. Found out it was a loose connection in the breaker box on the breaker terminal. It was overheating and tripping the thermal element on one side only.

Inspect each outlet (the inside) for arcing, and signs of overheating (discolored plastic, or copper).

Which leads to another question, if the house is old enough it might have aluminum wiring, so if you find that, it should be replaced.

RE: Weird Home Electricity

(OP)
House is 20 years old and the Al fiasco was pretty much done by 1980. All the wire is copper. The breaker that was removed was conventional (not GFCI). Then new breaker is also conventional. The electrician inspected the panel and couldn't find any char marks. I inspected it again on Saturday and couldn't find any char marks. I'm going to check the lugs on the common bus bar this afternoon to make sure they are all tight (if I don't respond here again, there was a problem that I was inept enough to let it kill me). I probably won't get to inspecting plugs till the weekend.

David Simpson, PE
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. —Galileo Galilei, Italian Physicist

RE: Weird Home Electricity

This part of your post "(if I don't respond here again, there was a problem that I was inept enough to let it kill me)" reminds me of a few years ago, my wife called me to tell me that our pump sprung a leak (the line from the pump to the pressure switch burst), and there was water spraying everywhere. I told her to open the electrical panel, and switch off the breaker for the pump...she said 'Sure, just hang on', and set the phone down....then I remembered that the panel was directly above the pump, and she was going to be standing in the spraying water, reaching into the panel to switch off the breaker...I was quite nervous until she happily came back on the phone.

RE: Weird Home Electricity

(OP)
Well my 10:00 meeting ended early and I was able to check the lugs on the common bus bar and they were all tight (and I lived). I'll check the plugs when I get time.

David Simpson, PE
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. —Galileo Galilei, Italian Physicist

RE: Weird Home Electricity

Being a knuckle-dragging mechanical type, I attack touchy circuits with brute force, as finesse usually fails me. (Typically this happens to me in an automotive setting.)

Disconnect everything, right down to taking wires off of outlet terminals and breaker. Reconnect everything one piece at a time.

RE: Weird Home Electricity

I have a carbon monoxide sensor that plugs into a regular electrical socket. Every time the power goes out, it sounds a very loud beep. Same when the power comes back on. Perhaps something as simple as this might help investigate when the power is cycling on and off.

RE: Weird Home Electricity

Can you jury rid a TRD meter and check all the wire runs for anomalies?
eg:
Check:
Panel to plug 1
Plug 1 to panel
Plug 1 to plug 2
Plug 2 to plug 1
etc.
Basically you need a scope and an oscillator. Skogs may be able to suggest the optimum frequency for testing.
If you get quite different readings from each end of what you think is one length of wire, then it may have a hidden branch that must be located.
If there is a reflection from the center of a wire length when testing from either end, it may be an indication of hidden damage.
I am concerned that there may be hidden damage that may develop into a fire hazard. Expensive testing may be cheap compared to a house fire.

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: Weird Home Electricity

At one time it was common for people tuning recievers (TV and radio) to use fiberglass screw drivers. The metal screwdrivers effected the magnetics of the tuners.
I sort of wonder if anybody makes them anymore.

RE: Weird Home Electricity

(OP)
I don't know what a TRD meter is. Google wants it to be a company that makes all sorts of instruments.

David Simpson, PE
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. —Galileo Galilei, Italian Physicist

RE: Weird Home Electricity

Canuck67,

If I am messing with my house wiring, I turn on a plug-in radio. If I can hear the radio, I don't touch the wires.

--
JHG

RE: Weird Home Electricity

David,

I suspect Bill means a ' TDR ' instrument rather than TRD, but it's the first time I've heard of one being deployed in a domestic setting. Interesting idea - we normally apply it to buried cables to localise faults.

If this problem was affecting my house I'd disconnect all faceplates then individually test each section of cable for insulation resistance and loop resistance. The IR check is easy, and the loop just requires a means of shorting the remote end together. Draw out a simple schematic (literally a box for a socket, a single line for a cable) as you go showing the sequence sockets are connected in. Start from the source and work outward until you find the problem. My guess is that you have something mis-wired hiding behind a faceplate, or a bad loop-in / loop-out connection.

RE: Weird Home Electricity

You are correct Scotty. Sorry for the typo.
We also use TDR instruments to locate faults in mineral insulated heat trace lines. I suspect that you may have a hidden tap connection somewhere, or a damaged cable somewhere. With the TDR you should see an echo from the end of the cable at a spacing on the scope that is proportional to the length of the cable. Tap connections and many faults should display an echo that will indicate the distance from the the test point to the fault or tap.
Basically an oscillator is used to send a high frequency signal down the cable. Any shorts, opens, taps or the end of the cable will reflect some of the signal. A scope is used to view both the applied signal and the reflected signal.
If you have access to a scope and are able to procure an oscillator, use a 10 foot length of cable and experiment with different scope ranges and frequencies until you find a combination that yields a usable indication from your test cable. You may then use the length of the test cable as a calibration standard for testing.

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: Weird Home Electricity

I like the radio idea, it beats using a night light as a power indicator.

RE: Weird Home Electricity

drawoh,

My idea for using the carbon monoxide monitor would not be to test the circuit before opening and working on it (your radio idea is a great idea for that). My idea would be to plug it in and go about your everyday duties. If the power cycled on/off while you were home, the loud beep would alert you. This would provide a small amount more information on whether it was only cycling off while the hair dryer was in use, or whether it was cycling on/off at other times when the outlet was not in use. A radio could possibly provide the same information, however, might be a bit disruptive having a radio on 24/7. The CO monitor I have is silent until the power goes off (also beeps when power comes back on - one loud beep for power interruption and that's it) It is loud enough to A) wake you up, B) hear it in the basement, C) hear it over the TV, etc.... My thoughts are that before ripping everything out and redoing the wiring, it might be a good idea to collect a bit more data on what causes it to cycle off.

Lots of other good ideas above. Good luck with diagnosing.

RE: Weird Home Electricity

Why not use an analog clock for that. It would let you sleep at night, and let you know how long the power was out.

RE: Weird Home Electricity

Canuck67,

The radio is turned on when I am sticking screw drivers and my fingers into light switches and other electrical devices. I need to know when the power is on.

It is turned on at other times too, but then, it is not a safety device.

--
JHG

RE: Weird Home Electricity

Insulated shank screwdrivers are still easily available.
They make it much harder to short something live to ground and/or yourself.

lots of good ideas here - someday I need to hunt down some funkiness in my own house's wiring.
Cheers
Jay

Jay Maechtlen
http://www.laserpubs.com/techcomm

RE: Weird Home Electricity

Get a tic tracer and map out the circuit while the whole thing is working. Then when you have the situation where the breaker is on but you don't have power to the last receptacle retrace the circuit and see where it ends.

RE: Weird Home Electricity

A survey with your infrared thermometer might yield a clue.

Mike Halloran
Pembroke Pines, FL, USA

RE: Weird Home Electricity

(OP)
I finally got a few minutes to get back to this and found that the #1 plug was a tiny bit different from plugs not on that circuit. I pulled out a couple of un-involved plugs and all of the wires were the same temperature (all 12 including the ground) on both plugs. On the #1 plug 2 wires (a pair of white/black) were the same temp as the uninvolved plugs. The white wire on the the other pair was 4°F warmer and the black was 2°F warmer. I took that as a smoking gun (pun intended) and replaced the plug (twisting the wires around the screws instead of using the push-in connections). We'll know if that worked if it never fails again, but the temperatures give me a feeling that maybe I did fix something.

David Simpson, PE
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. —Galileo Galilei, Italian Physicist

RE: Weird Home Electricity

Are there any nearby heating registers??

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: Weird Home Electricity

(OP)
No, house is forced air and this time of year the heater rarely runs. There is a floor vent on the other side of the (small) room, it hadn't been on in several hours when I took the temperatures.

David Simpson, PE
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. —Galileo Galilei, Italian Physicist

RE: Weird Home Electricity

zdas04,

Are all the receptacles GFCI? If the answer is yes, none of the wires hot or neutral should be on the load side of the GFCI. If the first receptacle in the line is a GFCI and the rest are not, the first GFCI should have the wires from the panel connected to the line side and the wires feeding the other non GFCI recepts should be on the load side. I have seen electricians do dumb stuff with multiple GFCI's in one circuit. If you could verify the hook up for me I'm sure I can solve your trouble.

Paul

RE: Weird Home Electricity

David - just for interest, any resolution to the problem?

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

RE: Weird Home Electricity

(OP)
[See post above] On November 8 I replaced the first receptacle in the string. A month later and there hasn't been a trip. I'll call it fixed if it doesn't do it again by 1/1/2016.

David Simpson, PE
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. ùGalileo Galilei, Italian Physicist

RE: Weird Home Electricity

z, I had a similar problem in the bathroom at our previous house. It was the lights. SWMBO was always the victim... taking care of business, and then <poof> lights would extinguish. Turn the switch off, let it sit for 30-60 minutes, power was back. I traced those lines from switch to service entrance and never found a thing wrong with it. After a year or two of complaining, I finally ripped all of the wiring out and replaced the 35+ year old 15AWG wiring with current-code 20AWG and was done with it. No problems since. I'm sure it was a tiny, tiny little thing as you found, but I just didn't care any more, I wanted the problem resolved.

Dan - Owner
http://www.Hi-TecDesigns.com

RE: Weird Home Electricity

(OP)
Well, so far replacing the first receptacle has resulted in zero trips since 12 December. 6 months without a trip is good, but I'm not ready to declare victory.

David Simpson, PE
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist

RE: Weird Home Electricity

(OP)
Spoke too soon. The problem is back. The breaker next to the one for the bathroom is for our swamp cooler. My wife thinks that maybe the problem is in the swamp cooler breaker that somehow messes with the bathroom breaker. I don't see how that could be, but I'm absolutely at the "replace something and see if it works stage". I'm on my way out of town so I won't get the swamp cooler breaker replaced for a few days.

Both breakers are duplex 15A. I don't know if there are any problems with the duplex breakers or not. None of the four loads are very big.

David Simpson, PE
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist

RE: Weird Home Electricity

Is it a weather related problem, rainy session, humidity -- after 7 or so months a very awkward problem by the sounds of it.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

RE: Weird Home Electricity

Have we asked yet? Does your home have aluminum wiring?
If the original breakers receptacles are about the same age, this may be age related failures.

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: Weird Home Electricity

(OP)
House is 20 years old. Build way after the Al wiring problems were identified. All wiring is copper.

I live in the high desert and our humidity is usually around 7% RH (hence the swamp cooler instead of AC). The panel is outside. The late afternoon sun shines on it in the winter, but by now it is pretty well shaded.

David Simpson, PE
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist

RE: Weird Home Electricity

There is generally recognised to be some interaction between adjacent MCBs, at least on the European designs. If you have a heavily loaded circuit then the heat in that MCB can bias the adjacent MCB curves such that they trip slightly light of where they would be expected to. My understanding of US wiring practice is that it uses many small radial loads rather than the smaller number of high power rings typical of British domestic practice, so I guess your swamp cooler could have its MCB loaded fairly heavily. Your wife might be right.

RE: Weird Home Electricity

I am starting to be concerned that there may be a hidden insulation break down somewhere. Do you have access to a Megger? I would disconnect the wires from the CB and with no devices plugged into the receptacles, do Megger tests of the wiring at 250 Volts, 500 Volts, and 1000 Volts.
Also feel the breakers. When a breaker is hot enough to affect adjacent breakers, the surface will probably be hot to the touch.

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: Weird Home Electricity

I was called in to find a similar type problem that electricians were not able to find, and discovered a circumstance with copper wiring I would not have thought possible..

I started by opening each wall switch and receptacle wiring box (there were both device types in this branch circuit), checking voltages and mechanical integrity of the device and wire nut connections.

When I got to a switch and outlet triple box in the bathroom , I found a neutral wire nut connection behaving as I would not have thought possible with copper wire.. Although the wire nut was mechanically tight, all neutral wires twisted properly seated in the wire nut, one of the wires coming out of the wire nut was intermittently open. By moving the wiring a very small amount with power applied, I saw the connection go open and closed with the movement of the wire.

It turned out that water from a plugged up condensate drain in an air conditioning air handler located directly overhead the wall in the attic had leaked water down inside the wall through the holes for the electrical wiring and repeatedly wetting one of the wire nut connections, causing contaminate or corrosion buildup in the wire nut connection, causing it to go intermittent. In the attic I found the wiring that went down into the wall and saw clear signs of past water leakage from the air handler down into the wiring holes bored into the wall stud plate.

The copper wire had a white coating on it which obviously was dielectric. There was sufficient wire length to cut back to expose fresh clean copper and a new wire nut fixed the problem.

Oddly enough and fortunate for the homeowner there was no black oxide coating on the copper wire from acidic corrosion, that is known to happen when the PVC insulation in NM type wiring gets wet. PVC insulating material when repeatedly exposed to water degrades producing acidic byproducts which will corrode copper.

RE: Weird Home Electricity

(OP)
Dan,
Are you anywhere close to New Mexico? I haven't fund anyone here that is willing to go beyond "let's replace something and see what happens"

David Simpson, PE
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist

RE: Weird Home Electricity

No, I live in North Carolina.. Good luck in finding the problem..

I certainly would or have an electrican take apart every wire nut connection in the branch circuit and verify their condition. Wires inside a wire nut have also been known to break and still mechanically stay inside the wire nut..

Copper work hardens with mechanical bending and can become brittle enough to break.

RE: Weird Home Electricity

Duplex 15A breaker, As in 2-poles? It makes no sense to have that type of breaker on a 120V circuit with 4 outlets like you are describing.

The problem is still that the power gets lost at all the receptacles with the breaker on, right? If yes, there has to be a problem with the wiring between the breaker and the first receptacle.

RE: Weird Home Electricity

Have you considered insects in the receptacles?

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: Weird Home Electricity

Interesting that the two breakers are side by side, as in some wiring the breakers on the X side of the 220V will share a neutral with the Y side of the 220V. Not for the whole circuit, but part of it.

Just a thought that maybe there is an issue with the neutral on the shared section of the of the two circuits.

RE: Weird Home Electricity

(OP)
I obviously used the wrong terminology. It looks like the breakers circled in yellow (maybe the right term is "tandem"?)

David Simpson, PE
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist

RE: Weird Home Electricity

Half size breakers. Tandem have one handle behind the other.
The half size or tandem breakers allowed a manufacturer to increase the rating of some lines of panel boards.
At one time, a major manufacturer used the same bus bars or strips in all panels up to 200 Amp rated panels.
However under the Canadian Electrical Code, not only the rating of the bus bars but also the number of breaker spaces are used to determine the maximum rating of a single dwelling panel board.
Excerpt:
8-108 Number of branch circuit positions
(1) For a single dwelling, the panelboard shall provide space for at least the equivalent of the following number
of 120 V branch circuit overcurrent devices, including space for two 35 A double-pole overcurrent devices:
(a) 16 — of which at least half shall be double-pole, where the required ampacity of the service or feeder
conductors does not exceed 60 A;
(b) 24 — of which at least half shall be double-pole
(i) where the required ampacity of the service or feeder conductors exceeds 60 A but does not
exceed 100 A; or
(ii) where the required ampacity of the service or feeder conductors exceeds 100 A but does not
exceed 125 A and provision is made for a central electric furnace;
(c) 30 — of which at least half shall be double-pole
Most panels could be uprated one at least one size after the introduction of the half size double breakers and the tandem breakers.
Some brands also offer half size single breakers.
(i) where the required ampacity of the service or feeder conductors exceeds 100 A but does not
exceed 125 A; or
(ii) where the required ampacity of the service or feeder conductors exceeds 125 A but does not
exceed 200 A and provision is made for a central electric furnace; and
(d) 40 — of which at least half shall be double-pole, where the required ampacity of the service or feeder
conductors exceeds 125 A and the dwelling is not heated by a central electric furnace.

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: Weird Home Electricity

I always get the rules screwed up for when and how many half-sized breakers can be used, so I just prefer to stay away from them altogether.

Dan - Owner
http://www.Hi-TecDesigns.com

RE: Weird Home Electricity

Try living in a 160 year old house that has been wired, and rewired many times...
I have outlets in the back of the house sharing breakers with lights in the front part, and upstairs... It's a nightmare to chase electrical gremlins, or add lights or outlets.

BTW, there are a ton of good ideas. I'll be dishing out some stars on this thread.

David
Connect with me on LinkedIn. http://lnkd.in/fY7-QK
Quote: "If it ain't broke, I must not've fixed it good enough"

RE: Weird Home Electricity

edit to add: I just saw the last entry was last july - color me minorly embarassed. I'd recommend moving on without reading.blush

speaking from 50+ years experience, with plenty of time packing tools, industrial motor and controls, as well as roping houses, couple of things are not sounding right. Just read through all this. I'm coming into this way late, and likely all this has been looked at. However:

Quote (zdas)

... From a new 15A breaker ... the wire goes to a plug in the hall bathroom, to a wall plug in the master bathroom, [b]then to a GFCI plug next to my wife's sink, and finally to a plug next to my sink. Four duplex wall outlets. ... Two to three times a year my wife yells at me that her hair dryer doesn't work. ...
Couple of questions:
That first receptacle in the hall bathroom - is it a gfci? Should be.
Is the second receptacle in the master bath a gfci? Doesn't have to be, but could be.
The hair dryer is plugged into wife's sink receptacle, the third receptacle in the string?

I would expect all the bathroom receptacles to be gfci protected. Since the branch ckt CB is not gfci, then my expectation would be:
The first receptacle (hall bath) to be gfci and be wired to protect all down stream. All downstream receptacles will be ordinary non-gfci. OR;

The first receptacle to be gfci, downstream receptacles gfci, wired to first receptacle line side. Until you get to the two receptacles by wife's sink and your sink. It sounds like the two sinks are side by side and are wired with your receptacle fed from wife's sink gfci.

If any of this is true, inspect/replace the first gfci receptacle in the hall bathroom.

If not, color me all wet and move on.

Hope this helps.

The worm

Harmless flakes working together can unleash an avalanche of destruction

RE: Weird Home Electricity

Brings up the question: Are you still having the problem zdas04?

Keith Cress
kcress - http://www.flaminsystems.com

RE: Weird Home Electricity

(OP)
The house has a swamp cooler. The breaker for it is located a couple of breakers away from the one on this circuit in the main panel. We were losing power to the circuit every day in September, but in early October I took the swamp cooler out of service and we haven't lost power since. We are thinking that there is something about the swamp cooler that is somehow involved in this mystery.

The receptacles in series are:
  • Hall bathroorm--not GFCI, been replaced since July. I know this one should be GFCI and I'm thinking that I'm going to make that change regardless of anything else
  • Wall outlet in master bathrrom--Not GFCI, replaced since July
  • Wife's plug--GFCI, replaced last year
  • My plug--Not GFCI, original.
If this problem stays gone until I turn the swamp cooler back on in the Spring, then I'm going to run a new wire (from my secondary panel) to the hall bathroom and try my best to forget this whole episode.

David Simpson, PE
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist

RE: Weird Home Electricity

Thanks for the come-back. I'm betting on either a loose connection on one of the outlets (probably a neutral [I've seen this twice!]) OR the neutral connection in the breaker panel is loose.. That might match-up with wiggling the box when setting/tripping the breaker magically 'fixing things' for a while.

We'll all wait for the final ruling.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Weird Home Electricity

(OP)
I have checked all of the neutral connections in the panel, I loosened each one a half turn and then retightened and pulled on the wire to make sure that the screw was actually bottoming out. They were all fine. I've replaced all but one of the receptacles and moved the connection points to the screws on the side, being very careful to loop the bends in the correct direction. For the one receptacle I didn't replace I pulled it out and repositioned the wires from the holes to the screws. If there is a loose common wire I haven't been able to find it.

David Simpson, PE
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist

RE: Weird Home Electricity

Wow.. Well. You've done everything I'd do. Next up would be to bleed a chicken. Then, burn the place down in hopes of driving off the devil spirits, rebuild and hope for the best.

Happy new years?

Keith Cress
kcress - http://www.flaminsystems.com

RE: Weird Home Electricity

One thing left to try:
Switch some breakers around and see if the problem stays or if it follows the breaker.
Re; the neutrals. If there are any shared neutrals, there may be field connections in junction boxes.

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: Weird Home Electricity

Just on general principles, you should reterminate all of the receptacles that are now connected using holes, to use just the screws. Those 'stab-in' connections were a bad idea.

Mike Halloran
Pembroke Pines, FL, USA

RE: Weird Home Electricity

Mike I think he has done that. I don't believe David's had a mystery power outage since the swamp cooler has gone out of service, so he may actually have it fixed. Has to wait for it to crap-out again to see if his outlet replacements and all screw terminations have done the trick.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Weird Home Electricity

It would seem that if the cooler is out of service and there hasn't been any problem, I would be giving the cooler a good going over to see if the problem is in the cooler ...as you have already indicated "We are thinking that there is something about the swamp cooler that is somehow involved in this mystery."

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

RE: Weird Home Electricity

(OP)
All of the outlet replacements and changing wire terminations did not do the trick. We had an outage the day before I took the cooler out of service and have not had one since. I'm going to have someone go through the cooler electrically to see if somehow it has some sort of short or cross connection to the bum circuit as soon as they can do it without freezing to death. I did check that it kept running when I opened the breaker to the bum circuit. If we can't find anything electrical, then I'm going to have to scrounge for a mechanical cause related to the cooler.

David Simpson, PE
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist

RE: Weird Home Electricity

Mechanical cause... ?

Possibility of water leaking out of the swamp cooler while in operation... and said water getting down into affected electrical circuit somewhere?

Would be similar to fault I mentioned above with corroded neutral caused by water leak out of plugged A/C drip pan.

RE: Weird Home Electricity

(OP)
I was thinking more about vibration issues. A water leak would have caused bigger issues than this intermittent electrical service (I had a roof-top swamp cooler leak from the pan once and it sprayed water out of the first ceiling vent to the point of damaging carpet and wallboard).

David Simpson, PE
MuleShoe Engineering

In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist

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