Dryer/receptacle mystery

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  #1  
Old 04-09-06, 12:34 PM
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Dryer/receptacle mystery

I will preface this by saying that our original dryer (that came with the house) worked fine for approx. 3 years...then began to fail. It would stop without warning, and would restart (upon pressing the start button) after a variable amount of time...sometimes right away, sometimes hours or days later.

Sears came out, said the dryer was old, we replaced it. I didn't delve into voltage measurements at the receptacle etc because it seemed logical that this 10+ year old dryer would "go".

New dryer...does the same thing. New dryer has a light inside (old one didn't) which is a sign whether it will start or not...light is dim, dryer won't start...light becomes bright again, it will. Of course even after it has started, it does not stay running for too long. On average it runs for 5 minutes.

2 Sears techs and 2 electricians came out and didn't solve the problem. 1st tech replaced door switch (nope), second said it was the service. 1st electrician said it was the dryer. 2nd electrician pointed out some ideas like replacing circuit breakers etc (I was just asking for troubleshooting advice...).

The dryer is located in the garage in a subpanel from the house. I replaced the dryer's breaker, as well as the breaker for the entire garage in the house panel. Nope again. The breakers are square D btw.

Latest testing...multimeter reads normal at dryer receptacle...L1 to ground, L2 to ground are equal. At the dryer's block, L1 to ground is around 30v, L2 to ground is around 210v. Light is dim, dryer won't run.

To make matters worse (ain't it the way!) I have measured a variety of things at different locations in the panel, at the receptacle, at the dryer over these months. At one point, when the dryer was out, the service coming into the garage measured at less than 100v...

So...I have a mess. If the dryer stayed at this dim state, not working, well that's one thing...but the fact that sometimes it works, and everything measures normally and balanced. Well...

One thing on my mind is whether a problem in the panel has now done damage to the new dryer causing additional intermittent issues.

It seems that everyone that came out to look wanted to ignore the fact that this happened on the previous dryer, after years of everything being fine.

Thank you very much in advance. This has been going on since August and driving me mad.
 
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  #2  
Old 04-09-06, 12:52 PM
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I strongly suspect a wiring issue at the receptacle or at the back of the dryer. You will very quickly destroy your dryer if you do not fix the problem.

Verify the connections at the dryer receptacle. Is this a three wire setup, or a four wire one? If it is only three wire go ahead and replace it with a four wire run. If it is a four wire run then make measurements from the neutral to both hot wires.

The grounded conductor is not making a good contact somewhere.
 
  #3  
Old 04-09-06, 12:59 PM
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Are there any other issues in the house? It could be on the power co. side. Start with them, It's free.
The next thing would be.. Is your dryer a 3 or 4 wire set up? Copper or AL? you could be loseing the neutral to the dryer.
If your bond/nuetral in your house is good, and the power co. lost theirs.Then you could be supplying the neighborhood with a neutral. Its possable this is the problem.

Check the neutral and bond(ground) to the sub panel.
 
  #4  
Old 04-09-06, 02:11 PM
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Originally Posted by ck623
At the dryer's block, L1 to ground is around 30v, L2 to ground is around 210v. Light is dim, dryer won't run.
Neutral is open (210+30=240).

This is a practical use for a voltmeter on a loaded circuit.


(If you really mean ground, is the dryer frame is bonded to neutral? It shouldn't be.
Is this a three-wire circuit out of a subpanel? If so, replace it with four wires.)

Readings while the dryer is not plugged in with the door open and the light on are meaningless.


> At one point, when the dryer was out, the service coming into the garage measured at less than 100v...

> sometimes it works, and everything measures normally and balanced.

Does it improve after a good rain?


> One thing on my mind is whether a problem in the panel has now done
> damage to the new dryer causing additional intermittent issues.

That's possible and possibly inevitable.


> It seems that everyone that came out to look wanted to ignore the fact
> that this happened on the previous dryer, after years of everything being fine.

They are wrong.

Turn off everything in the panel except the dryer.
Leave the dryer door open so the light is on.
Take readings at the panel.

One of your hots is open.

Go to your house panel.

Turn off everything but the subpanel.
Check your voltages on the breaker to the subpanel.


Turn off the breaker.

Tighten the lugs on this breaker.
Tighten the main lugs in the subpanel.
Tighten the lugs to the dryer on its breaker.

Turn everything back on.
 
  #5  
Old 04-09-06, 03:12 PM
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I will try and answer all questions that I am able...

After a good rain? It has rained here almost everyday for the last 45 days! (I am in CA).

It is a 3 wire receptacle. The wire to the dryer is connected to the case of the dryer.

The 2nd electrician made sure everything in the garage panel was tightened.

I don't know what this means:
Readings while the dryer is not plugged in with the door open and the light on are meaningless.

There have been no other issues with anything either in the house, or in the garage. What should I ask PG & E to do/check/monitor? We all know if I don't ask for something exact, they will blow me off.

I will run bolide's testing suggestions when the rain stops again...

Thanks all for the input. I've had it with this issue...it's become my white whale...
 
  #6  
Old 04-09-06, 04:18 PM
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You don't need to wait for the rain to stop. Your problem is that _somewhere_ you have an bad connection or a break in the wire. My guess is that you have a break in the neutral (grounded) conductor feeding the dryer, however the 100V indication suggests a bad connection to 'hot'.

It might be in the feed to the subpanel near the dryer, it might be in the cable to the dryer receptacle, it might be someplace else. There might be a bad splice or termination where the wire meets, or there might actually be a break in the wire somewhere. You need to find the break in the wire. The intermittent nature of your problem suggests a break where the separated conductors are very close together, possibly touching and releasing depending upon temperature or other external effects. These sort of breaks are the most dangerous, because they can produce lots of heat.

Bolide's diagnostic approach will probably hit all the splices that you need to worry about. I would also add checking the security of all 'neutral' connections associated with the circuits. Additionally, if any of the conductors involved are aluminium, you may need to worry about corrosion in the terminations.

The comment about readings being meaningless without a load has to do with the fact that without a load on the circuit the minute amount of current that can leak through a bad splice or termination is more than enough to give spurious readings on your meter. You need to put a bit of load on the circuit to drain any current flowing through a bad splice before the readings have useful meaning.

-Jon
 
  #7  
Old 04-09-06, 04:21 PM
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> It is a 3 wire receptacle.
I don't know under what exemption it exists.


> The wire to the dryer is connected to the case of the dryer.
This is undesirable.


> The 2nd electrician made sure everything in the garage panel was tightened.
So how about the subpanel feed in the house panel? Perhaps the neutral there is improperly landed.


> I don't know what this means:
> Readings while the dryer is not plugged in with the door open
> and the light on are meaningless.

We just did a thread in which this was a problem hindering proper diagnosis.


> There have been no other issues with anything either in the house,
> or in the garage. What should I ask PG & E to do/check/monitor?
We're thinking loose neutral.
But your testing hasn't shown the neutral to be loose external to your house.


> I will run bolide's testing suggestions when the rain stops again...
Could be a while? Are you at risk of lightning?

Now that I know your setup, I need more voltage readings at the garage panel with the power on (so avoid accidental contact, wear eye protection, etc.) and the dryer door open (of course!).
1. between the two hots (red and black) on the dryer breaker.
2. between the white wire that goes to the dryer and the ground bar of the panel (where the bare copper wires land).
3. between the neutral bus (where the white wires land) and the ground bar (where the bare copper wires land).

I can't believe that the electrician skipped these steps. But who knows?


Anyway, what happens is that the light in the dryer pull current off, let's say, L1. It puts it on the neutral. But the neutral is not connected back to the transformer, so this raises the voltage on the neutral to 120V except that you have something else on L2, perhaps even in the dryer itself, which uses some current and dumps it to the neutral cancelling an equal amount of current to what it takes to make the light glow.

Measuring L1 to neutral, you see only 30V because the neutral is really 90V wrt earth.

Now L1 is really 120V wrt earth. So let's call L2 -120V wrt earth. This way, 120V minus a negative 120V is 240V, so this is how you get 240V between them.

Measuring L2 to neutral, you see only 210V because the neutral is really 90V wrt earth and 90V minus negative 120V is 210V.


So you see, you connect your neutral to the transformer it goes to basically earth potential (within a fraction of a volt), and your problem is solved.


Your task, then, is to figure out where the neutral is disconnected/loose/corroded/damaged.

It could be inside or out. It could be your problem or the electric company's. That's why I'm not saying to call PG&E just yet.


(Note: your AC electric is not positive and negative as is DC. Rather, for mathematical purposes, it works well to use these numbers. The voltage between two points on the same leg is 0V. The voltage between any one and the earth is 120V. The voltage between two legs is 240V. So the subtraction works out great is they are treated as plus 120V and -120V. Interestingly, if you could measure wrt the high voltage line, one leg would add and one would subtract. But we never make a distinction this way.)
 

Last edited by bolide; 04-09-06 at 05:03 PM.
  #8  
Old 04-09-06, 04:27 PM
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Originally Posted by bolide
> It is a 3 wire receptacle.

I don't know under what exemption it exists.
bolide,

great catch.

ck623:
What bolide has noted here is that a 3 wire feed to a dryer is _never_ allowed from a subpanel. Since you are having problems anyway, I'd strongly recommend that you replace the dryer circuit with a 4 wire feed that has separate ground and neutral.

One additional question about your installation: is the subpanel in an attached or detached garage?

-Jon
 
  #9  
Old 04-09-06, 04:53 PM
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relative voltages

Originally Posted by ck623
At one point, when the dryer was out, the service coming into the garage measured at less than 100v...
A voltage is always measured between two points.
Do you mean 100V between L1 and L2?
When giving a voltage, it is necessary to precisely describe where the reading was taken.

Are there three wires or four coming from the house?

Anyway, if this reading was taken from a regular receptacle (not the dryer), this indicates a loose neutral between the house and garage, or possibly physical damage to the neutral somewhere along the way.

Having a four-wire installation throughout would give you an earth-referenced ground.
The problem with your neutral being 90V wrt earth would then be rather obvious by taking a reading between the two.
 
  #10  
Old 04-09-06, 05:37 PM
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missing comma

Originally Posted by winnie
What bolide has noted here is that a 3 wire feed to a dryer is _never_ allowed from a subpanel.
I've heard that interpretation but I didn't say it.

Do you have any idea what they are teaching students these days?

Did you know that three-wire installations are still okay in mobile homes and RVs? I guess Joe Tedesco, NEC expert, approves.
I had no idea.
So obviously the subpanel prohibition applies only if you use SE cable in an RV or MH. See?


(From Joe's website, quoting a written response of some students:
"If they've been installed recently and aren't located in a mobile home or a recreational vehicle, then they're in violation of 250.140, which requires the use of a 4-wire connection to the outlet.")
 
  #11  
Old 04-09-06, 07:58 PM
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I am waiting for the rain to stop so I am not drenched! The garage is detached, and the house panel is outside.

Whether a 3 wire feed to a dryer is allowed apparently did not concern the previous owner of my house.

There are 3 wires coming into the garage panel from the house panel. 2 are connected to the main breaker in the garage panel, the other to the neutral bus.

The wires to the dryer receptacle are connected to the dryer breaker, and the ground bus.

The time I measured 100v in the garage panel was from L1 to L2.

Part of the problem with taking all these readings is the inconsistency of what is happening when...sometimes the reading at the dryer receptacle is normal, sometimes it is not. One day, as I was testing in the garage panel, readings were changing in the time it took me to change between different areas in the panel...and the same areas were not the same twice.

And yes, I too am surprised that neither electrician bothered to really dig at this problem. At all. I've had a hard time finding an electrician at all...surprising living in a large city. It's been quite disappointing.

I need time to absorb all the things you have all contributed... thanks so much for all your time.
 
  #12  
Old 04-09-06, 08:22 PM
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Did you know that three-wire installations are still okay in mobile homes and RVs?
Really ??

in older days yeah some peoples done that by changing from 4 to 3 wire for dryer but the code for 4 wires in Mobile home been in code book for pretty long time [ i dont know what year they enforece it ]

RV useally are 3 wires set up [ black white and green ] useally are 120 volt loads but few larger one do have 30 or 50 amp at 125/250 volt cord connectors that genrally requred 4 wire not 3 wire at all for safety reason [ black red white et green ]

anyway if in garage if subfeed it is mantory to run 4 wire to dryer ya cant run 3 wire at all it get funky there.

Merci, Marc
 
  #13  
Old 04-09-06, 09:12 PM
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> Really ??

Apparently you never went to Pinkerton Academy.


> if in garage if subfeed it is mantory to run 4-wire to dryer

I don't know. I'm sure the Code didn't anticipate this.

But if the three-wire service is legal and the three-wire dryer receptacle was existing, then I see how it could be exempt.

Nonethless, four-wire is better all the more because the floor is in direct contact with the earth.
 
  #14  
Old 04-09-06, 09:28 PM
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Arrow

Originally Posted by ck623
The garage is detached, and the house panel is outside.
Oh boy!


> Whether a 3 wire feed to a dryer is allowed apparently did not concern the previous owner of my house.

Okay, just keep in mind that you must never say that you measured to ground. With three-wires you measure line-to-line or line-to-neutral. Saying that you took a reading "L1 to ground" is wrong because you have only three wires and no X0 reference on account of the faulty neutral.


> There are 3 wires coming into the garage panel from the house panel.

How far? Could you upgrade this run to four wires?
Is it a bare neutral?


> 2 are connected to the main breaker in the garage panel,
> the other to the neutral bus.

Correct. What colors are they?


> The wires to the dryer receptacle are connected to the dryer
> breaker, and the ground bus.

Ground bus?

There's the problem if the neutral bus and ground bus aren't bonded!


> The time I measured 100v in the garage panel was from L1 to L2.

I don't know what to make of this. Maybe you have two broken conductors. Maybe your probe wasn't touching what you thought.


> Part of the problem with taking all these readings is the inconsistency of
> what is happening when... sometimes the reading at the dryer receptacle is normal,
> sometimes it is not. One day, as I was testing in the garage panel,
> readings were changing in the time it took me to change between different
> areas in the panel...and the same areas were not the same twice.

This is normal for a bad neutral. Focus on the continuity of the neutral.


> I too am surprised that neither electrician bothered to really dig at this problem.

The symptom (30V+210V=240V) is obviously a bad neutral.
Anyone who has seen it before should know. I have never seen or heard of any other way to produce those readings in an isolated building like your garage.
 
  #15  
Old 04-10-06, 08:18 AM
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The reason I said "L1 to ground" is because the 3rd wire from the receptacle is connected to the ground bus in the panel. If this is incorrect, it came that way when we bought it and it worked until August (not to say that if it came that way it's correct!).

To run another wire from the house panel would necessitate going under the house, and then about 20 feet underground to the garage. It could be done...if I could find an electrician.

All 3 wires coming into the garage are black, with the one connected to the neutral bus wrapped in white tape.

I do believe that the 3 wire dryer receptacle situation is acceptable because it was existing...and CA is very...intense about all these sorts of things. If it wasn't acceptable, we would have been told.

Something just dawned on me...and please forgive my amateur blunderings...240V is very new me, as is dealing with the panels at all. How does the ground bus in the garage panel get grounded? There was no wire connected to it from the house...and I will check but it doesn't appear that it is connected to anything else, outside the garage (and in the ground)....
 
  #16  
Old 04-10-06, 08:36 AM
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Please confirm the following:

1) The garage is _detached_.
2) The feed from the house to the garage has three conductors, 2 hots and a neutral.
3) The garage panel has a separate ground and neutral bus.
4) The garage panel ground bus does not have any connections to water pipes, ground rods, etc.
5) The circuit to the dryer has two 'hot' conductors landed on a double pole breaker, and a ground conductor landed on the _ground_ bus.


And answer the following questions:
Is the garage panel neutral bus isolated from the panel enclosure? In other words, is the neutral bus sitting on insulators from the metal enclosure?
Does the garage panel have a bonding screw, strip, or other bonding means attached between the panel enclosure and the neutral bus? This might be a copper strip that goes from the enclosure to the neutral bus, or it might be a green screw that screws down from the neutral bus against the panel enclosure.
Is the ground wire feeding the dryer receptacle bare or insulated?

My hunch based upon what you've said so far is that the ground to neutral bond in your subpanel has degraded, and that the dryer is using the ground bus for the 120V loads.

-Jon
 
  #17  
Old 04-10-06, 08:42 AM
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Originally Posted by ck623
I do believe that the 3 wire dryer receptacle situation is acceptable because it was existing...and CA is very...intense about all these sorts of things. If it wasn't acceptable, we would have been told.
And just who would have told you? Don't think any home inspector you might have hired did his or her job thoroughly.

A sub panel in the same building as the main panel must be fed with four wire cable. The ground and the neutral must be separated in the sub panel.

A sub panel in a separate building from the main panel can be fed with either three or four wire cable. In some cases four wire cable is required. If fed with three wire cable, then the ground and neutral in the sub panel are the same. If fed with four wire then they are separate.

All new electric dryer installations must be four wire. In this case the ground wire and the neutral wire are separate.

Older installations were allowed to be three wire. In these instances the ground and neutral are the same.

It sounds to me like you have dealt with less than thorough electricians. Everything you have posed indicated a problem between your sub panel and the dryer. A competent and thorough electrician would have found and fixed this problem.

I suggest that you hire a competent electrician and have ALL your problems addressed.
 
  #18  
Old 04-10-06, 10:01 AM
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Originally Posted by ck623
The reason I said "L1 to ground" is because the 3rd wire from the receptacle is connected to the ground bus in the panel.
Yes, but to what is this ground bus connected?


> If this is incorrect

It is. Move it to the neutral bus.


> To run another wire from the house panel would necessitate going under the house,
> and then about 20 feet underground to the garage.
> It could be done...if I could find an electrician.

It should be done.


> All 3 wires coming into the garage are black, with the one connected
> to the neutral bus wrapped in white tape.

Okay. Is it the same way at the house panel?


> If it wasn't acceptable, we would have been told.

Don't count on it.


> How does the ground bus in the garage panel get grounded?

That's what we'd all like to know.

There should be a screw or strap between the neutral bar and the case (enclosure).


> There was no wire connected to it from the house...and I will check
> but it doesn't appear that it is connected to anything else, outside the garage (and in the ground)....

It should also be connected to an electrode. (But that won't solve your grounding problem.)


It must be the case that your ground is somehow, intermittently or accidentally, bonded in order for the dryer to have been working.
It should be deliberately bonded for your three-wire installation.
If you have no earth electrode, that's an obvious sign of an incomplete/incompetent installation.


Even if your dryer works, everything else still lacks a low impedance bond for equipment grounding which is very dangerous.

As Bob said, you need a competent electrician to address all the problems.
 
  #19  
Old 04-10-06, 12:52 PM
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For those of you interested in taking a moment to look, here are pics of the garage panel in question.

http://www.flickr.com/photos/[email protected]/

Racraft- Find me an electrician that is responsive and thorough and will listen to me, and I will hire him or her. Also, I don't assume anyone, ever, will do a proper job of anything. I also take anything I read on the internet with a grain of salt.

Jon- Answers to 1-5 are yes.

The neutral bus is inside the garage panel, along with the ground bus and all the breakers, if that is your question Jon.

Thanks for everyone's time.
 
  #20  
Old 04-10-06, 01:12 PM
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Judging from the photographs:

Your subpanel has separate ground and neutral bus, but there is no equipment ground wire running to the ground bus. This is problem 1. It is possible that the conduit feeding the subpanel is being used as the equipment ground conductor, but this is not reliable.

Your subpanel in your detached structure does not have a separate grounding electrode system. This is a requirement for subpanels in a detached structure. This is problem 2.

Your dryer receptacle _neutral_ wire is connected to the equipment ground bus of your subpanel. This is problem 3.

Your dryer receptacle is a three wire receptacle where neutral and ground share the same wire. This is problem 4.

On the plus side: your dryer receptacle is _right there_; you can replace the receptacle and run a proper neutral wire with trivial effort. There is absolutely no reason not to do this.

Somehow in the past the _equipment grounding connection_ between your main panel and your subpanel decayed. This is quite common when conduit is used as the equipment ground. The problems that your dryer developed are a symptom of this problem. However, had your dryer been _properly_ wired, you would have never noticed this.

I recommend the following corrective action.
1) Get an equipment ground conductor pulled from the main panel to the subpanel.
2) Get all of the EMT fittings tightened.
3) Add suitable grounding electrodes and a grounding electrode conductor at the detached structure.
4) Replace the dryer receptacle with a 4 wire receptacle, with separate hots, ground, and neutral
5) Replace the dryer cord with a proper 4 wire cord

-Jon
 
  #21  
Old 04-10-06, 02:37 PM
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Originally Posted by ck623
here are pics of the garage panel in question.
So the neutral wire from the dryer is green?
That tells you that the person who did this setup really didn't have a clue. I also suspect that the conduit is your ECG and it is poorly bonded to the messenger neutral at the mast. This means that the conduit has always carried the neutral current from the dryer, and it will continue to carry as much neutral current as it can. Only upgrading to quadruplex will solve this.

If you can bury a four-wire feeder, so much the better.


Anyway, that green wire needs to be white and to go to the neutral bus.

Move it over to the neutral bus. Use a short piece of wire to connect the neutral bus and ground bus together.
That will allow you to check for stable voltages confirm whether we have a correct diagnosis of the extent of the problem with your dryer.

This problem shouldn't have taken 2 minutes to diagnose. So the techs and electricians must not have had a clue either.

Obviously you haven't had good luck with electricians so far.
If it were my system, would be making at least all the changes than Jon suggested, the sooner the better.
 
  #22  
Old 04-10-06, 02:59 PM
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OK..before I am able to make all Jon's corrections, am I reading this correctly in that I should start with the following:

Remove the green wire connecting the ground bus and dryer receptacle with one that is white, and connects the neutral bus and the dryer receptacle...

And, connect the neutral bus and the ground bus by a wire?
 
  #23  
Old 04-10-06, 06:30 PM
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> Remove the green wire connecting the ground bus and dryer receptacle with one that is white

There's not much point in using more wire.
You'll just be changing it again when you upgrade to four wires.
We all know it's technically the wrong color.
What matters most is where it is connected.

> connect the neutral bus and the ground bus by a wire?

Correct. A main bonding jumper because right now you have only three wires from the house.

Once you have four wires, the neutral and the ground must not be connected at all anywhere in the least.
So again, this is just a temporary band-aid until you can find yourself a real electrician. The purpose is so that if a ground fault occurs, it has a path home.

What we'd all like to do is to tell you to shut off the breaker at the house to the garage and leave it off until the electrician says it ready to go again.

But realistically I don't know that you are willing to do that. Perhaps you are. I will say that I more confidence in your ability to figure out what is wrong than I do in your ability to find a good electrician. Maybe on the phone tell the candidate you read 30V between L1 and neutral and 210V between L2 and neutral. If he hasn't a clue or says something unrelated to a loose/faulty neutral connection, move on. If he says it must be a bad neutral, hire him, he know more than the last five guys. If he says he'd need to see it, tell him he can see it all he wants on his own time.
 
  #24  
Old 04-10-06, 07:13 PM
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You know if I had just said take the wire off the ground bus and attach to the neutral bus, someone would have pointed out that it needed to be white!

OK I switched the wire from the ground bus to the neutral one and hooked a wire between the neutral and ground.

Flipped all the switches and the light came on nice and bright and everything measured properly.

Of course now it just needs to stay that way!

And I have turned off the breaker to the garage and will only turn everything on to test some more tomorrow.

I am going to call electricians tomorrow and play "who gets the job".

I really appreciate everybody's time here...as I've said, this has been going on since August and keeping me awake - P
partially because of the inconvenience, partially because I just couldn't figure it out.

I don't know if you were able to figure out that I am woman from my posts, but the female factor is real when dealing with any male service people. In almost all my experiences, when I tell them that I've replaced a breaker, or that all the tools are mine, not my husband's, there is a look of surprise and confusion. I know it is not mean spirited, but it does create a barrier to communication.

I'll let you all know how it turns again..and thank you very kindly for your time.
 
  #25  
Old 04-10-06, 09:47 PM
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Thumbs up

> now it just needs to stay that way!

It will stay that way. But don't take a false sense of security from this.

All you did was to prove that what we thought was wrong is indeed what is wrong.

So now you know the answer to the problem.

If you look back to post #2, you see:
Originally Posted by racraft
The grounded conductor [neutral] is not making a good contact somewhere.
If you look back to post #3, you see:
Originally Posted by lectriclee
you could be losing the neutral to the dryer.
If you look back to post number four, you see:
Originally Posted by bolide
Neutral is open (210+30=240).
That's exactly how I would have answered had you called me and said, "Dryer is on three-prong cord. At the dryer's terminal block, L1 to neutral is around 30V, L2 to neutral is around 210V. Light inside dryer is dim."

If think you're looking for an electrician who doesn't have to guess.


As for the 100V you saw between L1 and L2, it could be (as winnie [Jon] said) that one of your hots was open and your meter was reading a phantom voltage.
Depending on what you replace, it either won't matter, or the electrician you get will be smart enough to hunt it down.

Anyway, if you find anything unusual during your testing, check back with us rather than risk continuing to run your dryer.

-----------------------

The bonding jumper wire you added is probably too small, so don't be offended if the electrician tells you so. It's better than nothing. It wouldn't hurt to post a close up photo showing the jumper and the green wire from the dryer.

Be sure to advise the electrician that the jumper is there so (s)he can either use the correct jumper (if you stay with your three-wire feeder), or omit it entirely if you upgrade to four-wire feeder (as we all recommend). If he insults me, that's okay.


> I have turned off the breaker to the garage and will only turn everything on to test some more tomorrow.

Does testing include drying your laundry?


> I am going to call electricians tomorrow and play "who gets the job".

Good luck!
 
  #26  
Old 04-11-06, 01:39 PM
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Electrician is on his way! Of course I was unable to be succinct in explaining my problem...6 months of troubleshooting will do that.

Any advice in how to sum it up in less than the 300 words I poured down the phone?

You guys have been so patient....thank you so much.
 
  #27  
Old 04-11-06, 03:41 PM
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OK, electrician just left. He said I (we!) fixed the problem with the moving of the wire to the neutral bus, that it never should have been on the ground bus. He also said the jumper between ground and neutral was not necessary, that the panel was adequately grounded, and that it was now wired properly (under CA code).

He corrected something in the dryer's receptacle (someone had wired what was the ground, and is now the neutral unnecessarily, and dangerously onto the screw at the back of the receptacle's metal box).

So....that's about it. Now I get to stop hanging wet clothes all over the house).

I know you all feel it's best to run that 4th wire out there..but if it meets the code, I'm ok with it. Not to say that I'll let it be the next homeowner's problem, but if things are working and safe, I am not going to force the issue right now.

You guys are awesome!!!!! You have no idea what kind of effect this has had on my mental state. Thanks again!
 
  #28  
Old 04-11-06, 04:05 PM
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I believe that your electrician is wrong, but there is only so far one can fight these things over the internet

The feed to your subpanel is supposed to have 4 separate conductors (note exception below), two _hot_ conductors, 1 _neutral_ conductor, and 1 _equipment ground_ conductor. The hots and the neutral are expected to carry current; they are how you use the electricity. The equipment ground conductor is not supposed to carry current during normal operation, but must be able to carry enough current to 'trip' your circuit breaker. In other words, your equipment ground conductor _must_ be a very good conductor.

The metal conduit that the wire runs in is permitted to be used as the equipment grounding conductor.

Since the equipment ground conductor is _supposed_ to be a good conductor, and since the equipment ground conductor is _supposed_ to be bonded to the neutral at your service entrance, then when your dryer was connected to the equipment ground rather than the neutral, your dryer _should_ have worked. The fact that your dryer didn't work is very strong evidence that the equipment ground conductor is _not_ properly connected somewhere. So the use of the metal conduit as the equipment may 'meet code', but it is _broken_.

Additionally, I am quite certain that the use of a three wire dryer connection is not, and was never, permitted from a _subpanel_. I would be greatly surprised if California permitted this, even if they have a modification to the code which still permits three wire dryer circuits from the main panel. Given that this would be trivial to change (you have access to everything _right there_, no cables to pull, no headaches), I would have changed this even if California did permit it.

Finally, a _detached structure_ always requires grounding electrodes. It is possible that in the past this was not the case, and that this is 'grandfathered'.

The exception that I mentioned above is that for a _detached structure_ in certain circumstances you are permitted to use a three wire feed. This exception does not apply in your case. I believe that your conduit is your required equipment ground conductor, and that it has corroded somewhere and no longer functions correctly as such.

-Jon
 
  #29  
Old 04-11-06, 04:49 PM
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get a gas dryer...
 
  #30  
Old 04-11-06, 05:15 PM
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Jon-

From the California Electrical Code:

A subpanel in a garage or other detached accessory building, which is fed by the main service at the house,
must have a separate grounding electrode. If the feeder from the main service is only 3 wires (2 hots and
neutral) the grounding electrode conductor at the subpanel must be bonded to the neutral. If the feeder has four
wires (2 hots, neutral and ground) the grounding electrode conductor at the subpanel must be isolated from the
neutral, even though they are bonded together at the main service. This seems odd, but there is a good reason
for it. If you cut the neutral wire of an active circuit and hold one cut end in each hand, you will be electrocuted.
If you do it to a properly installed ground wire, you will not. But when you bond the neutral and ground together,
the ground wire from that point back to the beginning of the circuit shares the current carried by the neutral and
can electrocute you. For that reason, the bonding together of these two wires must only occur at the origin of the
ground wire.

Ok..so I need a grounding electrode. How do I not already have one? And how do we know I don't have one? (I am not doubting I don't, I just want to know how I find out). And it needs to be bonded to the neutral...

So now what? I knew it wouldn't end with the electrician leaving somehow...who installs a grounding electrode? I know this sounds stupid, but its kind of awkward to call an electrician and say "I need a grounding electrode" when the system existed before I moved here, and worked. (Not to say it was done right of course!)

You mentioned pulling the 4th wire to the dryer receptacle would be trivial to change..doesn't it need to go from the house panel out to the garage panel or am I misunderstanding that?

A woman's work really is never done!!
 
  #31  
Old 04-11-06, 05:24 PM
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I don't understand what constitutes an electrician in CA. You got another loser.



Here is a statement of the problem in less than 300 words:
  • If your panel is properly grounded, then the dryer would have worked hooked to the ground bar.
  • If you have a three-wire feeder, you have to have the jumper between neutral and ground and you have to have an electrode.


  1. So your dryer did not work on the ground bar. That proves that the panel is not effectively grounded as required by Code.
  2. You do have a three-wire feeder. You do not have an electrode as required by Code.
  3. You do have neutral current on the conduit which is forbidden by Code.

In short, the electrician's opinion is wrong.
Your installation can't meet Code anywhere in the USA.

For your own safety, keep the jumper in place with the shortest, heaviest copper that you can -- or figure out where the main bonding jumper screw or strap is supposed to be and install one.
Without the jumper, it is not safe by any stretch of the imagination.
 
  #32  
Old 04-11-06, 05:33 PM
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You could call an electrician and request that they bring the grounding of the sub-panel up to current code, and evaluate the integrity of the equipment grounding conductor back to the main panel.

You are quite correct that the equipment grounding system must be electrically continuous back to your main panel. This is not done by running individual wires from each receptacle back to your main panel, but instead by running the wires to the ground bus in the sub-panel, and then making sure that the ground bus in the sub-panel is electrically connected back to the main panel.

Right now, my guess is that the metal pipe that the other wires are in is what is _supposed_ to serve as the equipment grounding conductor.

The quote from the CEC seems to match my understanding of the NEC. It doesn't mention dryer circuits, but a three wire dryer circuit from a _subpanel_ sets up exactly the situation that they caution against. The frame of the subpanel is connected by an equipment grounding conductor. The frame of the dryer is _bonded_ to neutral (in a three wire circuit), thus the risk is that you could get a shock between the dryer frame and the subpanel frame.

-Jon
 
  #33  
Old 04-11-06, 05:39 PM
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> A subpanel in a garage or other detached accessory building,
> which is fed by the main service at the house,
> must have a separate grounding electrode.

Correct.


> If the feeder from the main service is only 3 wires (2 hots
> and neutral) the grounding electrode conductor at the
> subpanel must be bonded to the neutral.

Correct.


> If the feeder has four wires (2 hots, neutral and ground) the
> grounding electrode conductor at the subpanel must be
> isolated from the neutral, even though they are bonded
> together at the main service.

Correct. You need this type of installation to avoid objectionable neutral current.


> I need a grounding electrode.

Correct.


> How do I not already have one?

Obviously what you have has some deficiencies.


> And how do we know I don't have one?

Because if you did, there would be a wire (GEC) going to it from your panel.

The wire should be heavy, solid, bare copper.
I didn't see it in the photos. You can look for it.

> I knew it wouldn't end with the electrician leaving somehow...
the so-called "electrician".


> who installs a grounding electrode?
You could.


> it's kind of awkward to call an electrician and say "I need a
> grounding electrode"

What's worse is that he might try to talk you out of it.
You can install it yourself.


> You mentioned pulling the 4th wire to the dryer receptacle
> would be trivial to change..

It would be, but ...

> doesn't it need to go from the house panel out to the
> garage panel

There are two parts: from your garage panel to the dryer and from the house to the garage.

As you surmise, the former is almost of no value without the latter since the dryer is within two feet of the panel anyway.
 
  #34  
Old 04-11-06, 06:26 PM
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Ok I believe I've got it! (hope hope).

The conduit is supposed to be acting as the EGC in this setup, and is only doing so intermittently.

I have 2 hots and a neutral, now hooked properly to the receptacle, but neither the receptacle, nor the panel, and of course not the dryer, are continuously ground because of the wonky conduit-as-EGC-connection. (Yes they use "wonky" in the NEC).

A grounding electrode would serve as the ground (in place of the conduit-as-EGC or pulling an EGC from the main panel) for the subpanel. Then I would have 4 wires, and would wire a 4 wire dryer receptacle.

Yes...or no?
 
  #35  
Old 04-11-06, 07:07 PM
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Originally Posted by ck623
Ok I believe I've got it! (hope hope).
Sorry!


> The conduit is supposed to be acting as the EGC in this setup

Maybe. You haven't provided a photo of the connection between your house and garage or said whether it is aerial or underground.


> I have 2 hots and a neutral, now hooked properly to the receptacle,
> but neither the receptacle, nor the panel, and of course not the dryer,
> are continuously grounded because of the wonky conduit-as-EGC-connection.

Maybe. We need that photo or a better description.


> A grounding electrode would serve as the ground (in place of the conduit-as-EGC
> or pulling an EGC from the main panel)

No, never under any circumstances.


> Then I would have 4 wires, and would wire a 4-wire dryer receptacle.
> Yes...or no?
No.
The missing electrode is simply another error in the installation.
It has nothing to do with four-wires or EGC and is not the biggest problem with the installation.

So long as you have only three wires, you need the jumper and the jumper is the EGC path for effective grounding.

I hope you don't mind if I ask, are you imported?
 
  #36  
Old 04-11-06, 07:42 PM
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Yes...I am imported from New Jersey.

Maybe if the bloody electricians would stop calling everything by similar names GEC, EGC etc, the rest of us wouldn't get so confused.

The connection from house to garage goes from the house panel (on the side of the house), under the house, comes out on the other side of the house, then goes underground to the garage. The only thing you see at these entrance and exits is a junction type box or a semi-cylindrical box in which the 3 wires turn a corner. There is no aerial wiring except from the street to the house.

I am not generally thick, so what am I screwing up here. One of the things I don't understand is, if the ground and neutral are connected back at the main, and the dryer should have worked properly when connected to the ground bus but didn't, then why is it working ok (thus far) connected to the neutral bus? If they are connected at the main, shouldn't it work equally poorly on either bus? Quote below:

-Since the equipment ground conductor is _supposed_ to be a good conductor, and since the equipment ground conductor is _supposed_ to be bonded to the neutral at your service entrance, then when your dryer was connected to the equipment ground rather than the neutral, your dryer _should_ have worked. The fact that your dryer didn't work is very strong evidence that the equipment ground conductor is _not_ properly connected somewhere. So the use of the metal conduit as the equipment may 'meet code', but it is _broken_.
 
  #37  
Old 04-11-06, 07:50 PM
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Hey, I'm from NJ also, maybe I can translate

Your dryer didn't work before because your EMT conduit has a poor contact somewhere between the garage panel and the house panel. Now that you have moved the dryer neutral to the "real" neutral connection, that path is now copper wire (the white taped one), and its working fine now.

In the process of determining this problem, a bunch of sharp eyed electricians here have also seen some issues that are not per code, and they would like to see those resolved as well.
 
  #38  
Old 04-11-06, 07:52 PM
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Someone from the old country always helps..

So, going forward, what is dangerous in my system as it exists right now?
 
  #39  
Old 04-11-06, 07:54 PM
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Alas, not quite.

The flaky (another technical term) conduit is one problem. This is a serious safety issue. The flaky conduit means that a breaker might not trip in the event of a 'ground fault' where some 'hot' wire contacts metal that should be safe to touch. If a hot wire touches your panel enclosure, then a breaker _should_ trip. But with the flaky conduit, you might be left with the panel energized.

The lack of a ground electrode is another problem. This is a minor safety issue.

The problem that you need to solve is the flaky conduit, so that you have a good path for 'fault current'. You need to re-establish the electrical connection between the panel ground bus and the main ground bus at your main panel.

The neutral-ground bond that bolide suggests will provide the fault current path, and is probably a reasonable 'stop-gap', however it is not code compliant and does introduce its own safety issues. Clearly, your conduit _used_ to be a viable equipment ground conductor, because the dryer _used_ to work. This means that there is a metallic ground current path from your garage back to your house, faulty though it may be. The bond connection in the subpanel introduces the 'current in the ground wire' issue that your quote from the CEC mentioned.

My only recommendation on this issue is to check all of the conduit connections that you have access to, and make sure that they are tight. If this doesn't improve the quality of your equipment ground, then I recommend getting a ground wire pulled in with the feeder wires.

-Jon
 
  #40  
Old 04-11-06, 08:10 PM
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ck623,

Sorry, I didn't see your later posts. This question is spot on:
Originally Posted by ck623
One of the things I don't understand is, if the ground and neutral are connected back at the main, and the dryer should have worked properly when connected to the ground bus but didn't, then why is it working ok (thus far) connected to the neutral bus? If they are connected at the main, shouldn't it work equally poorly on either bus?
The difference between the neutral bus and the ground bus in your subpanel is that your neutral connection is in perfect shape, but your ground connection is decayed. So the neutral bus in the sub-panel is connected correctly to the ground/neutral bus in the main panel, but the ground bus in the sub panel is not reliably connected to the ground/neutral bus in the main panel.

The thing to keep in mind is that you have _four_ conductors from your main panel to your subpanel. These conductors are three wires and a pipe, and the pipe is broken.

-Jon
 
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