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Old 07-24-2010, 04:49 PM   #1
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strange electric problem in new house, hot ground!


I have a strange and dangerous problem in my new house wiring. Or part of the wiring anyway. I have my dryer connected via an 8-2 circuit (2 hots and a ground, no neutral). The electrician just used that setup because my dryer only has a 3 wire plugin already.

Anyway, the problem occurs when I try to turn the dryer on. it doesn't come on but what it does do is send power onto the ground & do some other weird stuff to my electric. I've measured both legs of power when I push start and on one phase of the panel the voltage goes down to around 30 volts and on the other side it goes up to 240ish. It seems like its putting most of 1 phase onto the ground ( and yes I can measure 120 between ground and neutral only when the dryer button is pushed), my ground and neutral are separated in my panel, neutral is not bonded to the panel because there is a separate main breaker at my electric pole. The dryer is the only thing that causes any problems. The hot water heater, ac compressors, etc none of them do anthing like this to the power. I've tried the dryer on other 220 circuits and get the same result, even tried 2 different dryers.

I'm not a licensed electrician but a fairly handy diyer. I know how to be safe around electric. I do plan to get a licensed electrician here to troubleshoot the problem as I think it is more serious than just the dryer circuit. I think something is shorted somewhere or somethin else weird going on. I've had one electrician look at it and he couldn't determine anything due to lack of time, he has another full time job. Anyway, just looking for ideas to help whoever comes by to troubleshoot.

I keep wondering how in the heck can 120 volts get into my ground in the first place. Shoulnd't it kick off some breakers or something?? Should I have the neutral bonded to the panel?

any ideas appreciated. Again, I will not try anything on my own just want to understand better and maybe give some ideas to the electrician.

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Old 07-24-2010, 04:53 PM   #2
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More than likely either the dryer receptacle is miswired or the dryer cord is miswired. 4 wire circuits have been required for several code cycles. With the 3 wire circuit you are using the combo neutral/ground wire must be connected to the neutral buss in your panel and not the grounding buss. This is exactly why three wire cicuits are no longer allowed.


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Old 07-24-2010, 05:04 PM   #3
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1) You are not permitted to install a 3-wire dryer receptacle off a sub-panel in this manner.
2) The dryer requires a NEUTRAL connection, not a ground connection
3) The 3-wire configuration (NEMA 10-30) is NON-GROUNDED -- it gets its "ground" through the neutral
4) Chances are your sub-panel is not properly grounded in the first place. You said you have separate grounds and neutrals in there .... where is the grounding connection originating from?
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Old 07-24-2010, 05:32 PM   #4
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1) You are not permitted to install a 3-wire dryer receptacle off a sub-panel in this manner.
2) The dryer requires a NEUTRAL connection, not a ground connection
3) The 3-wire configuration (NEMA 10-30) is NON-GROUNDED -- it gets its "ground" through the neutral
4) Chances are your sub-panel is not properly grounded in the first place. You said you have separate grounds and neutrals in there .... where is the grounding connection originating from?
Ok, I had 2 different electricians here and I think one of them probably didn't know that the 3 wire 220 circuit was for a dryer so he probably didnt connect the 3rd wire to neutral (myself I just didn't know you couldn't). But my dryer is set up for the 3 wire so I asked my electrician to just leave it, in my ignorance and he probably thinks its perfectly safe.. I know better now!

So would a dryer connected improperly like I might have do something like what I explained? If so then I understand why the 4 wire is code now. I'll probably have him change it either way.

I didn't think my 200 amp was a subpanel. But the electrician explained that anything after a main disconnect was considered a subpanel. Because the power company connected the main disconnect at the pole, any panel after that is a subpanel.

As far as I know the ground in my 200 amp panel just comes from a grounding rod outside, I know there is a heavy bare wire fastened to long grounding rod stuck in the ground outside. It's about 15 feet away. Is that what you were asking? Is that considered a proper ground? The power pole is also grounded in the same way out front by the power company.
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Old 07-24-2010, 05:38 PM   #5
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You said you have separate grounds and neutrals in there .... where is the grounding connection originating from?
By that I just meant that all the neutrals are on one bus bar and all the grounds are on the other. The ground bar is tied directly to the panel and then to the ground rod, the neutrals are not connected to the panel at all. The electrician told me this is how it is done because I have a separate disconnect at the pole. I don't understand that part. Or maybe I misunderstood what he told me.
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Old 07-24-2010, 05:55 PM   #6
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strange electric problem in new house, hot ground!


Quote:
Originally Posted by area123 View Post
By that I just meant that all the neutrals are on one bus bar and all the grounds are on the other. The ground bar is tied directly to the panel and then to the ground rod, the neutrals are not connected to the panel at all. The electrician told me this is how it is done because I have a separate disconnect at the pole. I don't understand that part. Or maybe I misunderstood what he told me.
if you have an actual disconnect at the pole, your panel in the house is a subpanel . Since your ground and neutral are apparently not bonded at this panel I will not go into why it could have been legally but at one time, it was legit to do so.







How many wires do you have coming from the disconnect on the pole into the panel in your house? You might have another problem altogether here.

and you say this is a new house. Does that mean new to you or new construction?
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Old 07-24-2010, 06:04 PM   #7
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It is new construction, but rural so no inspections, which could be a bad thing sometimes. BUt I have licensed electricians, doens't mean they couldn't have made mistakes or could be underexperienced..

ANyway, I have 3 wires comgin from the pole. I bought the actual service wire from the power company. The 3rd smaller wire is connected to the neutral bar. The two hots are connected to each phase of the panel. I'm pretty sure that's right?? The voltages all measure 120 to ground or neutral.
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Old 07-24-2010, 06:18 PM   #8
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strange electric problem in new house, hot ground!


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ANyway, I have 3 wires comgin from the pole.l.
bingo!!

you must have 4 wires from the pole to the house if the neutral and ground are not bonded in the house (and just to add; the ground and neutral should not be bonded in the house in case you thought about anything different)
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Old 07-24-2010, 06:43 PM   #9
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Originally Posted by nap View Post
bingo!!

you must have 4 wires from the pole to the house if the neutral and ground are not bonded in the house (and just to add; the ground and neutral should not be bonded in the house in case you thought about anything different)
I don't understand. My third wire would just be connecting the ground to the pole, that just goes to the ground anyway. I already have a ground going to the same place (ground). I guess it might be code but I bought the wire from the power company and I assumed they knew what to sell me. And if I look in the power company disconnect, the neutral and the ground are bonded. I don't see how that would cause operational problems like I am seeing. Although it might not be as safe as a 4 wire, I think it should still work..

I will ask them about putting on the 4th wire but it would be nearly impossible to run it through the 150 feet of underground conduit to the pole. Are there any other options at all that would be safe?
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Old 07-24-2010, 06:54 PM   #10
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Area 123

I don't think your understanding what NAP is saying. If you only have 3 wires from the main disconnect and connected the neutral of the dryer branch circuit (you thought it was ground) to the grounding bar of the house panel and the neutral and ground are not bonded then there is no complete circuit back to the transformer for the 120 volt motor. Therefore you will get the test results your stating no matter what dryer you use or what 240 volt circuit you use.

You dryer motor cannot operate because you essentiually have an open neutral. So the 120 volts feeds thru the motor to the grounding bar.

Remember the dryer is both 120 volts and 240 volts so it must have a neutral connection with the transformer ... not to ground (earth)
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Old 07-24-2010, 06:57 PM   #11
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strange electric problem in new house, hot ground!


a residential electrical system is currently a 4 wire system. 2 hots, a neutral, and a ground. The ground and neutral MUST be bonded at the first disconnect for a service. Yours can't be because you do not have 4 wires running to the disconnect.

Your ground as it is is useless for the purposes of creating a low resistance pathway for ground fault currents which are needed to affect a breaker trip.

In other words,if you have a dead short to ground in your house, the breaker will not trip. There will not enough ccurrent flow to make the breaker trip but it will energize the grounding system and cause an extremely dangerous situation.

Quote:
I don't understand. My third wire would just be connecting the ground to the pole, that just goes to the ground anyway
No, it would be connecting the ground to the neutral which is what it takes to make a dead short to the grounding system in the house trip a breaker.

Quote:
I guess it might be code but I bought the wire from the power company and I assumed they knew what to sell me.
POCO people generally do NOT know the electrical codes. They do very little with them.

Quote:
And if I look in the power company disconnect, the neutral and the ground are bonded.
but where does that ground go? to a rod I suspect. That means you are trying to use the ground to provide a low resistance pathway for a fault current to return to it's source. Not happening.

Quote:
I don't see how that would cause operational problems like I am seeing.
because when you connected what should have been a neutral to the grounding system that is incomplete, you had no 120 volt power, only 240. A dryer timer and motor are typically 120 volt. The 240 is used for the heating element so, you had no power to run anything but even worse, you essentially created what happens when you lose a neutral which means, you tried to run a voltage though the 120 volt parts of the dryer but it was not 120 volts. It was the 240 divided amongst the devices bases on their resistance.

Quote:
Although it might not be as safe as a 4 wire, I think it should still work..
the dryer would work when you hook the neutral to the neutral but your breakers will not trip on a fault current and that could basically allow anything in your house to be subjected to extremely high currents.

so, it is a very unsafe situation and no, it does not allow the system to work properly.

so, this is why inspections are a good thing. Not only will they cause an installation to be proper and safe, they will prevent electricians that have no idea what they are doing from working in the industry. You need to find an electrician that knows a neutral from a ground.


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Last edited by nap; 07-24-2010 at 07:02 PM.
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Old 07-24-2010, 07:07 PM   #12
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strange electric problem in new house, hot ground!


Ignoring the code issues already discussed, let's talk about the actual problem.
Where are you measuring the voltages? The readings you describe indicate to me an open or loose neutral connection. Is the problem only on the dryer circuit or is the whole house affected.
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Old 07-24-2010, 07:13 PM   #13
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Measure voltages with respect to the metal cold water pipe entering your house. Sand it first so you make good contact.

In general, make a reading and interpret it before proceeding, and load down your voltmeter with an incand. bulb for those voltages measured at 120v or less.

If I ever read 30 vac on a DVM on my house wiring I'd start unplugging stuff.

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Old 07-24-2010, 07:18 PM   #14
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strange electric problem in new house, hot ground!


while I respect joed, I would suggest NOT taking any more readings and not playing with this until you correct the MAJOR installation error of the electrical system. It is dangerous and it should be remedied before any individual part of the system is worked on.

due to the fact there is no proper grounding system in place that would allow an accurate reading, any readings involving the ground system would not be dependable.
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Old 07-24-2010, 07:39 PM   #15
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strange electric problem in new house, hot ground!


I quickly modified a drawing so hopefully no major mistakes.

Hope this helps
Attached Thumbnails
strange electric problem in new house, hot ground!-unbonded-3-wire-sub-panel-1.jpg  

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