What would cause lights to shut off when pressing a dryer start button AND MORE!!?

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cowboyjwc

Moderator
Staff member
Location
Simi Valley, CA
The 120 volt loads on the "good" side will not have any problems, they will see same voltage they normally see, it is the "dead" side that is backfeeding through a 240 volt load that will see problems. If light loads are all that is present one may not notice any problem, but the more load is added the more the 240 volt load that is in series with it will drop the voltage. Now place a somewhat heavier load suddenly in the circuit and it will drop voltage to a very low level.

I've fixed more problems of this nature involving underground faults then because of a failed pole on a breaker. Next on the list is probably blown main fuse - the symptoms are same because the problem is still a loss of continuity of an ungrounded conductor
to the source.
Yeah we're in agreement.
 

kwired

Electron manager
Location
NE Nebraska
I'd have to take your word on that. We use a gas dryer.

Probably has exact same 120 volt motor as an electric dryer from same product series. Heat element is only part that is 240 volt and that circuit is not closed until centrifugal switch in the motor is in run position. Same centrifugal switch probably need closed on the gas dryer before combustion controls are active as well.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
Some dryers may also have an air flow sensor that locks out starting the gas burner if the air is blocked or the fan is not running. Modern gas furnaces definitely do that
 

gnuuser

Member
Location
Nw.Pa.
VICTORY!!! The issue has been resolved. There was a bad neutral in one of the three underground boxes. It was a chore trying to find them all, but it is over :roll:

reminds me of an issue from my apprentice
we went to the site and the exhaust fan wouldn't run! he was a bit puzzled
he checked the hot conductor to neutral (nothing) hot to ground voltage present. and people getting a tingle at the water fountain! (wired on the same circuit)
after hearing this I immediately thought neutral short.
after checking 4 junction boxes found neutral wire shorted to the cover and insulation burned on the supply neutral (open neutral at the splice)
one section of pvc conduit between panel and 1st junction box (no ground conductor)

after a fair amount of cussing we ripped out the old wire, replaced the pvc with rigid and pulled new conductors
a good example for him to learn by for troubleshooting and the methods of repairing it
 

electricalist

Senior Member
Location
dallas tx
From what I can tell it was between the transformer and the meter.
So the OP had to dig up the poco service to house ...i may have assumed it was overhead because it sounded like a older house. If it was u/g xfmr to meter..I hope the poco wouldnt splice the service conductors..
 

John120/240

Senior Member
Location
Olathe, Kansas
......................................................................................................................................................................................................... It appears as though they have a 70A breaker that goes approx. 150ft. underground to a 200A panel at the main house. .......... I don't understand why they would be feeding their entire home off of a 70A breaker.

VICTORY!!! The issue has been resolved. There was a bad neutral in one of the three underground boxes. It was a chore trying to find them all, but it is over :roll:

Good for you. I was willing to bet it was a lost hot.

Why in the name of all that is good and right were there three underground boxes?

From what I can tell it was between the transformer and the meter.

So the OP had to dig up the poco service to house ...i may have assumed it was overhead because it sounded like a older house. If it was u/g xfmr to meter..I hope the poco wouldnt splice the service conductors..

I am not sure ? Was it a detached building separate from the main house ? The only way that I know to get THREE underground junction boxes is to be really careless with a shovel.
 

hurk27

Senior Member
The last time I had this problem was in a trailer park where the POCO was installing new street lights and feeds, they bored underground and nicked many of the feeders going to trailers, all aluminum it took about two weeks and we started getting calls, we had three trailers that as soon as you tried to load either leg or both the voltage would drop turn on an electric water heater and it would go to 0 volts between legs and or between each leg and the neutral, the best one was one where they had the central air on, it didn't have any time delays so the compressor would try to come on right as soon as the thermostate was calling for it, it would cycle the power would go out then as soon as it dropped back out the power would come on and it would cycle again the lights would just keep comming on the off then on and off till they turned the air off, using my underground locater I found the bad spot and dug it up, both hots had the insulation compromised and the aluminum conductor had turned to white powder, it still conducted enough so that when there was no load you would read 240/120 volts H-H and H's_N, if you only loaded one leg then that leg would go to zero volts, I had to make a underground repair to save cost using a simple double ended lug and heat shrink that has the hot melt glue in it, also I coated the connection in dielectric grease before applying the heat shrink, the neutrals insulation was also compromised and it too also started dissolving into the white powder also known as aluminum oxide but is was still conducting but would have met the same end just would take longer.

If you find that after applying a 240 volt load you loose all voltage line to line as well as line to neutral then you most likely have a damage feeder, ask the home owner if anyone had done any digging in the path from this house to the main house you might get lucky and find the spot where the feeder was hit, my locater has a fault locater that looks looks a bow saw, it will pin point the fault every time so maybe you can find someone who has a underground locater or even find a place to rent one?

Also to confirm that you have a bad underground feeder, turn off both the main breaker at the remote house and the feeder breaker at the main house, using an ohm meter high scale (10k or above) test between the hots and neutral and hot to hot, also you can use an amp meter if you turn the main off in the remote house then turn the feeder breaker on at the main house and using an amp meter to see if the hots are drawing current with the load off at the remote house, if you get any kind of reading then you know for sure the feeder is bad, locating the bad spot can be tricky but asking the owner about any digging may or may not help as it could have been damaged by a rodent, even ask if anyone drove any stakes in the ground, anything that could have compromised the wires insulation, if they are aluminum conductors I would say that the damage would have happened 3 to 4 weeks before they started noticing the problem, copper can be quite a bit longer up to maybe a few months, having an underground locater is priceless in this kind of trouble shooting, I found mine on E-Bay for $1200.00 new it cost over $5k but it has so many functions and mutable frequency's and well as many mode of operations that allows me to not only locate utilities underground but many other things it was a must when I had my trencher and backhoe as the utility locates only cover their conductors and or water lines and sewer, privet lines are the homeowners responsibility and will not be located by them, Ill try to post the info on the one I have but there are many other ones out there that can do the job at a much less cost, they just are not as flexible and has as many features.

Also don't get side tracked by thinking that the feeder breaker should have tripped, many times the resistance between the conductors and Earth will never get low enough to trip the breaker, remember a 8' ground rod that has the NEC minimum 25 ohm resistance contact with earth will only produce 4.8 amps of current, not even enough to trip a 5 amp breaker much less a 70 amp, so don't let this be a distraction and get you off track thinking it has to be something else.

Good luck:thumbsup:

Here is the locator that I mainly use for most of my locates:

3M Dynatel 2273 Cable Pipe Fault Locator

Click on the link above, Google it and you can find them as low a $900.00 but be careful as you might not get all the pieces of the kit when the price is that low, don't get scared of paying these kind of prices as trust me if you advertise doing underground locates and fault location and master doing it you will get the jobs and you can make back the price you pay for it many times over, I would be lost without mine as it has spoiled me, once you have mastered the art of locating things underground or as I sometimes use mine for following conductors in walls or concrete you will try to figure out how you ever got things done without one, so if you can get one for $2k or less grab it, it's priceless for jobs like yours, if you get one post back and I can give you some pointers that will help you get started and some tricks that I use to find exactly where the fault is, as in your case since the conductors are some what still conducting, you can use the 60hz frequency by applying power to them and load them at the remote house to cause the voltage to drop as low as you can get it to then follow the conductor from the source end and it will drop off at the bad point, then use the A frame fault locator to zero in on the exact location, the hand tracer unit can be set to 60hz to follow live lines without using the transmitter it also has frequencys for phone and cable that you can use to locate them without using the transmitter ) I usually get within 6" of the bad spot every time saves allot of digging, it will also tell you how deep the conductors are and is very accurate, I had a coworker fill in a trench on me before we had it inspected so I use it to confirm to the inspector how deep the conductors were, the first time I showed him that it said 28" then I dug down to show hit that it was exactly 28" so after that he would allow me to go ahead and fill my trenches as long as I would let him use the locator to see how deep they were, he actually got the city to purchase one for them to use as it was also great for checking swimming pool EPG's and many other things.

Ya I know I could be a sales man for these LOL but really I have found different equipment over the years that makes our work so much easier like wire tracers and such and this is one of them that after getting use to using it and learning all the little tricks it has saved me so much work and made me allot of money to boot, it can also pay back when you have underground conductor failure that you are still covering under warranty, as you can find the exact point of damage and show them what caused it like I did in the trailer park then the owner can go after the person who damaged it, in these cases I document everything and take allot of photos that show exactly what damaged the conductors, in one case the phone company had an outside contractor do some cable boring in a subdivision that damaged allot of our street light runs, they tried to refuse to pay for the damage but after I e-mailed them the photos they paid for everything.
 
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hurk27

Senior Member
O well I just seen that there was a second page (my preference is set to 40 post per page) so most of my above ramblings is not needed (what I get trying to post after coming in from working two doubles in a row)

But I left it maybe something someone could use at another time.

From you initial post I would have never though that it was a bad neutral just because you answered someone else about lights getting only dimmer and not brighter which is always a result of a bad neutral, I also find it amazing that because of the lights going totally out when the drier was started the other leg would have to had 240 volts to the neutral which meant they should have lost some equipment if not GFCI's, smokes or anything that was on the other leg?

Basically when you have lost the main neutral to the panel the side that has the heaver load takes the voltage down on that leg but the voltage goes up on the other leg proportionally to the amount the first leg is loaded to, lets say that the dryers 120 volt load is on the "A" leg and it pulls it down to 0 volts, this actually makes the neutral in the panel the same as the "A" leg so anything connected to the "B" leg would see 240 volts, if it only dropped the "A" leg to 30 volts, then the "B" leg would have 210 volts to the neutral bar, kind of like a see-saw effect,I have actually seen where the furnace kicked on and dropped "A" leg to less then 20 or 30 volts then when the voltage surged on the "B" leg it caused a surge strip's MOV's to short out and pull the "B" leg down to 0 volts so that the loads on the "A" leg started burning out which meant that about everything in the house that was on or plugged in at the time was damaged, the furnace lost its control board, the microwave was shot, power supplies in TV's and computers were all fried some of the little wall wart PS for phones and such all burned up one actually caught fire, some of the incandescent light bulbs actually melted the glass, probably one of the worst ones I had ever gone on, all traced down to who ever installed the service didn't make sure that the neutral in the meter was under the screw when they tightened the screw down, how they didn't notice that the screw went in further is beyond me, but the wire was not even under the screw, it worked for almost 2 years like this before it lost contact, I took photo's for the home owner that showed that the neutral was not even indented by the screw as well as it showed the screw all the way in bottom out in the lug, their insurance company used the photo's to go after the EC who had wired the house and they won, but we are talking about allot of damage, I think it was over $50k with all the electronics, they had no less then 5 large LED TV's as well as 4 computers, not including all the GFCI's and smokes, GDO, most newer TV's and computers will do fine on anything from 120-240 volts as the switch mode PS are made for it so they can be used overseas, but these had a switch that changed the voltage.

So it can be very important to make sure that you make your neutral connections as good as you can, they were lucky they were home and turned off the main in time as a fire could have easily been started and then it would had been the cost of the whole home, in this case just one of the wall warts caught fire but it could have been worse.


Glad you found the problem and I hope there wasn't much over voltage damage that normally is found with a lost neutral fault.
 

hurk27

Senior Member
Probably has exact same 120 volt motor as an electric dryer from same product series. Heat element is only part that is 240 volt and that circuit is not closed until centrifugal switch in the motor is in run position. Same centrifugal switch probably need closed on the gas dryer before combustion controls are active as well.

Correct most dryers have an extra set of tips on the centrifugal switch brought out and connected in series to the heating element contactor coil or gas valve control supply, I ran into this on my dryer when I couldn't get the gas valve to open, had no power to the control which also had the low and high temp and flame out sensors all in series, these were all on the newer ceramic glow igniter systems, on the older pilot light types it removed the power to the main gas but the pilot light would stay lit, never seen a air flow switch on a dryer as many would keep running even if the vent hose was blocked, this would cause the high temp to kick out though and even the flame out sensor to open, this detected if the flame was not going into the tube to the back of the dryer, it sat just above the opening where the burner fired into the tube so if for any reason the flame wasn't being drawn into the tube it would hit this sensor and trip it, furnaces has it mounted to the fire box just above the burners, so if you had a negative building pressure or if the exhaust flue gets blocked the flame would start running up the front of the fire box and trip this sensor.

I was very intrigued by the way the ceramic igniter system worked, its a very simple system the uses two coils on the main gas valve, a hold close and a open coil, the hold close coil is in parallel with the ceramic igniter which then feeds the voltage to the open coil, the resistance of the ceramic is high when it is cool this keeps the hold closed coil from allowing the valve to open until the ceramic heats up which shifts the voltage to the open coil, if the ceramic is damaged worn or cracked the hold closed coil gets most of the voltage and the valve won't open, and is the reason most of the time why the dryer wont heat, but in my case it was the centrifugal switch, this system was also used on many newer electronic ignition furnaces and water heaters.
 
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