Dedicated 240v - Ground, no ground

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  #1  
Old 08-23-06, 02:47 PM
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Dedicated 240v - Ground, no ground

I am installing a 50A 240v GFCI protected outlet. It will be powering two electric hot water heater elements for a kettle. Due to the GFCI, obviously it can only be be used for 240v service. If someone trys to connect to neutral and get 120v, the breaker is going to trip. So the question; do I really need to install an outlet and cable with a ground wire?

From my understaning, code now requires that all 240v carry a ground wire. In my case it is kind of a suspenders and belt solution. I know that it really isn't any sweat off my back and probably not a ton more money to just install the outlet with a ground, but I figured I'd ask anyway.

FWIW, my house was built in 2000 and all 240v service (stove, dryer, AC) does not have a ground wire.
 
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  #2  
Old 08-23-06, 02:54 PM
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Always a ground.

It serves a different purpose than the GFCI although the GFCI does sort of make up for a lack of ground but not in all situations and circumstances, there are other reasons including a code requirement.

I would have to go back to some older code books but I find it hard to believe a ground wasn't required in 2000.
 
  #3  
Old 08-23-06, 03:12 PM
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You are mistaken about the neutral and a GFCI. A 240 volt GFCI breaker has a spot for a neutral connection. Items like hot tubs need a neutral, as do GFCI protected multi-wire circuits. A properly wired 120/240 volt circuit will not trip a properly installed GFCI breaker unless a ground fault occurs.

Your circuit requires a ground. Even in 2000 the circuit would have required a ground.

Whether or not you need to install a receptacle or hardwire your setup depends on what the kettle requires. If the kettle comes with a cord and plug, then install a receptacle to match it. I suspect that it does.

As for the circuit, I would run a three wire plus ground circuit (240/120 volt) even if the kettle did not require it. Some day you might replace it with one that does, or want the neutral there for some other reason.
 
  #4  
Old 08-23-06, 03:26 PM
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I'll go with a ground. It gives me more flexibility.

I understand that a 240v GFCI has a neutral connection. I was trying to not intermix the terms because people often do when discussing 240v. I also contend that you cannot run 120 off a 240v GFCI breaker without tripping it. The GFCI monitors the two hot wires and will trip on any balance fault between the two. If you try and run 120 by hooking into the neutral, the GFCI will trip because it sees an imbalance between the two 120v lines. People commonly misunderstand how a GFCI works and think that a path to the ground wire is what trips it. An imbalance is what trips it, not current through the ground wire.

I assure you that all 240v service in my house does not have a separate ground wire. I have looked in the load center and every 240 line comes in with black, red, and white. Nothing else. No bare wire, no green, nothing. I also assure you that it was built in 2000. I don't know when the NEC required separate ground wires for 240v, but evidently the code was not adopted in my area at the time the house was built. Just because the NEC code required it in 2000, that doesn't mean that my local codes used that requirement at that time.
 

Last edited by stangbat; 08-23-06 at 03:37 PM.
  #5  
Old 08-23-06, 03:40 PM
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I assure you that all 240v service in my house does not have a separate ground wire. I have looked in the load center and every 240 line comes in with black, red, and white. Nothing else. No bare wire, no green, nothing. I also assure you that it was built in 2000. I don't know when the NEC required separate ground wires for 240v, but evidently the code was not adopted in my area at the time the house was built. Just because the NEC code required it in 2000, that doesn't mean that my local codes used that requirement at that time.[/QUOTE]

You can assure us all day long but that does not make it right or legal. When you have 3 wires with a 240 volt circuit, you have a wire to be used for ground. Now with a 120/240 circuit, you obviously do not. Are you speaking of 240 or 120/240 circuits.

So to define the legality of it, you need to consult you local building department to see what code was used in 2000, if any.
 
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Old 08-23-06, 03:46 PM
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Your understanding of 240 volt GFCI circuit breakers is incorrect. A 240 volt GFCI circuit breaker compares not only the two hot wires, but also the neutral wire. This is why the neutral wire connects to the breaker, and why you can use a GFCI circuit breaker for a multi-wire circuit serving, for example, a kitchen.

In the year 2000 I do not believe it was possible to buy NM cable assemblies for the often used wire sizes that did not have a ground wire.

I assure you, in the year 2000 a ground was required for 240 volt circuits. Perhaps you have conduit that supplies the ground, but regardless, if your house is properly wired, there is a ground.
 
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Old 08-23-06, 03:52 PM
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You can assure us all day long but that does not make it right or legal. When you have 3 wires with a 240 volt circuit, you have a wire to be used for ground. Now with a 120/240 circuit, you obviously do not. Are you speaking of 240 or 120/240 circuits.

So to define the legality of it, you need to consult you local building department to see what code was used in 2000, if any.
This is exactly the confusion I was trying to avoid. I know that on a 240 service the white wire is used as a ground. So yes, my 240v service is grounded...with a white wire. I was trying to get the point across that my 240v service does not have a separate bare or green ground wire.

What I was asking is if I should run my 240 service with three conductor plus ground. I.e. black, red, white, bare wires. Sorry for the confusion. I thought I was being clear, evidently I just made things more confusing.

And I'm not saying that my 240v service with red, black, and white is necessarily legal. I was just explaining why it could be legal and probably is in my area for the time my house was built.
 
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Old 08-23-06, 03:55 PM
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It was not legal in 2000 to wire 240 volt devices using the white wire as a ground. Also, in 2000, it was required for electric dryers and electric ranges to be wired using FOUR wires.
 

Last edited by racraft; 08-23-06 at 08:46 PM.
  #9  
Old 08-23-06, 03:58 PM
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Originally Posted by racraft
Your understanding of 240 volt GFCI circuit breakers is incorrect. A 240 volt GFCI circuit breaker compares not only the two hot wires, but also the neutral wire. This is why the neutral wire connects to the breaker, and why you can use a GFCI circuit breaker for a multi-wire circuit serving, for example, a kitchen.

In the year 2000 I do not believe it was possible to buy NM cable assemblies for the often used wire sizes that did not have a ground wire.

I assure you, in the year 2000 a ground was required for 240 volt circuits. Perhaps you have conduit that supplies the ground, but regardless, if your house is properly wired, there is a ground.
Thanks for the 240 GFCI info. I know a couple of people that tried to run 120 off their 240v GFCIs and had it trip. I'll have to double check with them as to why they were having problems. If I can run 120 off that breaker it will make things easier as I have some other equipment I need to run.

I'm going to have an electrician double check all my work before I flip the switch if it makes anyone feel better.

From my understanding, a locality adopts the NEC code and then enforces it. Usually this is several years after the code comes out. The NEC may have said you need four wires when running 240v in 2000. If my area had not apopted this revision of the code, my house may not have had to have four wires, right? Is this not a distinct possibility?

Thanks for the info and help.
 

Last edited by stangbat; 08-23-06 at 04:10 PM.
  #10  
Old 08-23-06, 06:26 PM
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seeing is believing

Originally Posted by stangbat
I know a couple of people that tried to run 120 off their 240v GFCIs and had it trip. I'll have to double check with them as to why they were having problems.
Had to be something wrong.
There is no reason that it shouldn't work if the neutrals are connected correctly.


> I'm going to have an electrician double check all
> my work before I flip the switch if it makes anyone
> feel better.

It is about facts not feelings.


> From my understanding, a locality adopts the NEC code and
> then enforces it. Usually this is several years after the code
> comes out.
Not so. Localities may adopt whatever the current version is to be automatically upgraded, or they might act much more quickly than "several years".

> The NEC may have said you need four wires when running
> 240V in 2000. If my area had not apopted this revision of
> the code, my house may not have had to have four wires,
> right? Is this not a distinct possibility?
It's vaguely possible. What don't you post some high-resolution close up photos for us to have a look?
 
  #11  
Old 08-23-06, 07:22 PM
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Originally Posted by bolide
Not so. Localities may adopt whatever the current version is to be automatically upgraded, or they might act much more quickly than "several years".

> The NEC may have said you need four wires when running
> 240V in 2000. If my area had not apopted this revision of
> the code, my house may not have had to have four wires,
> right? Is this not a distinct possibility?
It's vaguely possible. What don't you post some high-resolution close up photos for us to have a look?
I did some checking and although the 2005 NEC is the current code, right now my county enforces the 2002 NEC.
http://buildingcodes.jocogov.org/default.htm

So I imagine what happened is exactly what I said. Construction was started on this house in late 1999/early 2000. The code that was enforced when it was built was probably a revision several years prior to that. Whatever code revision they were enforcing, it must have been before the revision that required four wires for any 240v installation.

I don't think that is it so improbable that this happened or that it wasn't perfectly legal at the time my house was constructed. Anyway, here is a pic. I have some others, but the wire enters the load center towards the back and there are other wires in the way. I can post them, but this is the clearest example.

http://img215.imageshack.us/img215/962/240nk3.jpg

Here is the dryer outlet just for kicks:
http://img214.imageshack.us/img214/598/dryersu2.jpg

There is no fourth wire leading to any 240v service in my home. I'm not argueing right or wrong, that's just the way it is. It is all NM three conductor (black, red, white) without a separate ground. I wish it had a separate ground.

I'm sorry if I'm coming across as confrontational. I'm not trying to make anybody mad or step on toes. I appreciate the help, and I learned something about 240v GFCIs.
 
  #12  
Old 08-23-06, 07:36 PM
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You keep referring to this as "240v". A dryer is 120/240v. It requires a neutral, always has. Previous codes allowed the ground to be bonded to the neutral. You have the last of these allowed. This is why there is no ground. They used that cable to save money. This was probably a large contractor who bought large quantities of this cable so it was worth it to him at the time.
Earlier you stated older 240v circuits did not need a ground. This was not nearly so. Only certain circuits were allowed to use the "no ground" exception. A 240v A/C unit for example is typically a straight 240v load. This has required a separate ground conductor for eons. This type of load is very different from a 120/240v load like your dryer.

If wired correctly a 240v, or a 120/240v, load will function perfectly fine on a GFI protected circuit. Wired correctly is the key here.

Question: Why GFI? 240v circuits in a home do NOT need GFI protection, unless of course the Mfg specs it.
 
  #13  
Old 08-23-06, 07:54 PM
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Originally Posted by Speedy Petey
You keep referring to this as "240v". A dryer is 120/240v. It requires a neutral, always has. Previous codes allowed the ground to be bonded to the neutral. You have the last of these allowed. This is why there is no ground. They used that cable to save money. This was probably a large contractor who bought large quantities of this cable so it was worth it to him at the time.
Earlier you stated older 240v circuits did not need a ground. This was not nearly so. Only certain circuits were allowed to use the "no ground" exception. A 240v A/C unit for example is typically a straight 240v load. This has required a separate ground conductor for eons. This type of load is very different from a 120/240v load like your dryer.

If wired correctly a 240v, or a 120/240v, load will function perfectly fine on a GFI protected circuit. Wired correctly is the key here.

Question: Why GFI? 240v circuits in a home do NOT need GFI protection, unless of course the Mfg specs it.
I know 240v has ground. I know. I know it is the white wire. I was not trying to say that there wasn't a ground. I know that 240v uses two hot wires that are out of phase. I know a dryer also has 120v components. I understand the difference between neutral and ground. I know you can get killed even with a GFCI. I know you should ground *everything*.

In trying to be clear, I seem to have confused everyone. I was trying to ask whether I needed to install my new 240v service with four wires. In other words, a separate "only" ground wire.
The only reason I asked the question in the first place is because I was planning on only using 240v on this circuit, no 120. Therefore it would be grounded with the white wire. I was wondering if the second dedicated ground wire was really necessary. I am going to install four wire cable.

I was wrong about running 120v off a 240v GFCI. I admit that. I made a mistake. But I can count and I do know my colors. Hopefully the pics show that.

I am using a 240v GFCI because this is powering two boil kettles. Water will be used around this. The GFCI is just in case. I know that a GFCI isn't fail safe. Everything will be grounded.

I'm glad I learned something but I'm sorry I opened this can of worms. Hopefully somebody else is learning too.
 
  #14  
Old 08-23-06, 08:09 PM
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"I understand the difference between neutral and ground."

I'm sorry but you do not....because of this:

"I know 240v has ground. I know. I know it is the white wire."

The white wire is NOT, and never was, a ground wire.
A straight 240v residential circuit is two hot wires and one ground of some sort. None of which should be white.


I think this whole thing is getting blown way out of proportion and off track.

Tell us exactly what it says on the rating plate of this kettle. Voltage and amperage (or wattage). Then we can go from there with what cable to use, breaker size, etc.
It is not whether you intend to use 120v on this circuit. It is whether the unit requires 120v.
 
  #15  
Old 08-24-06, 12:01 PM
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Do I need to install an outlet and cable with a Ground wire?"-----

Art 250.110, Equiptment Connected by Permanent/Fixed Wiring Methods ( "hard-wired")----

"------ metal (surfaces) of ( in-place) equiptments---shall be Grounded"

Art 250.114 ( Cord & Plug connected )----

"--- metal (surfaces) of cord-and-plug connected equiptments--- shall be Grounded."
 
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