3 wire (washer/dryer) configuration question

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  #1  
Old 04-11-11, 05:03 PM
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3 wire (washer/dryer) configuration question

Hey, all!

We bought a used stackable washer/dryer combo that came with a 4-wire power plug. However, our receptacle is for a 3-wire config. I hooked everything up (got the 3-wire power plug), but not sure if the unit is grounded. I know that the neutral wire should have a ground strap or a new wire grounded to the chassis. I'm attaching some pics for you to see. Is the green wire in the pic the ground or do i need to get the neutral/ground strap?
Thank you, all!



 
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  #2  
Old 04-11-11, 05:27 PM
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The green wire is the machine ground. You need to add a wire jumping from the neutral (White) wire to the green screw at the bottom of the machine.
 
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Old 04-11-11, 07:26 PM
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I do not see how to do that without either double-lugging or using a polaris. That neutral also seems a little to close to the ungrounded conductor.
 
  #4  
Old 04-11-11, 09:22 PM
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If you look closely you will see that the green lead connected to the frame is long enough to reach the neutral connection block, which is where it goes when using a three-wire connection. If using a four-wire connection then the green lead is connected to the frame as shown and the green lead from the cordset is connected to the other green hex-headed screw in the frame.

Justin, it is perfectly acceptable to have two lugs (eyelet style) on the same terminal.
 
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Old 04-12-11, 12:39 AM
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Is this a Whirlpool by chance? If so, that green may already be your bond strap (we came across this a couple days ago in another thread). If you have a meter, test for continuity between green and white.
 
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Old 04-12-11, 07:22 AM
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Thank you all for quick responses!
Furd, should i unhook that green wire and hook it up to the neutral then?

If using a four-wire connection then the green lead is connected to the frame as shown and the green lead from the cordset is connected to the other green hex-headed screw in the frame.
that's exactly how it was setup when the 4-wire cord was still attached.

Is this a Whirlpool by chance?
forgot to put the brand in the op. it is a GE washer/dryer

p.s. i forgot to mention something. when the breaker was still on, i tried to unplug the plug from the receptacle and got "shocked" when trying to unplug it. it felt weird, not like when you get a static shock at all, but more like when you try to put two magnets together and you can feel that resistance. is that because of the lack of ground? i am an electrical newb, btw
 
  #7  
Old 04-12-11, 10:43 AM
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Yes, connect the green wire to the neutral lug. It was incorrectly done when it had the four-wire cordset.
 
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Old 04-12-11, 01:21 PM
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It was incorrectly done when it had the four-wire cordset.
i thought you said that's how it was setup for the 4-wire? green from the machine to that screw and the green from the cord to the other screw.
 
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Old 04-12-11, 02:12 PM
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Okay, to get away from any confusion as to what WAS and what is NOW follow these directions.

For a four-wire cordset the green pigtail of the dryer needs to be connected to the green hex-head screw on the dryer frame and the green equipment ground of the cordset needs to be connected to the other green hex-head screw on the dryer frame.

For a three-wire cordset the green pigtail of the dryer needs to connect to the middle terminal of the wiring terminal block along with the neutral wire of the cordset.
 
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Old 04-12-11, 03:20 PM
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yeah, i got that it just threw me off when you said that it was incorrectly set up for the 4-wire cord before.

since i'm a newb, here's a question: why does the neutral terminal provide a better ground connection than just the screw on the dryer?
thank you, all!
 
  #11  
Old 04-13-11, 11:47 AM
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The neutral terminal does NOT provide a "better ground" than the screw in the machine frame.

You have to understand the purpose of the neutral connection AND the equipment grounding connection. The neutral connection carries the unbalanced current from the two "hot" leads back to the source. If your machines were like mine (Asko, made in Sweden) then they would be strictly 240 volt machines and no neutral or equipment ground would be necessary for operation. BUT, American made machines use 120 volt motors and 120 volt control circuitry and THAT is the ONLY reason why a neutral connection is required. The equipment ground connection is still not necessary for normal operation.

Many years ago (I have read it was for the war effort during WWII to reduce domestic use of copper) the National Electrical Code (NEC) deemed it acceptable to use the neutral connection as an equipment safety ground on certain 240/120 (dual voltage) appliances. This was not as safe as having a completely separate equipment grounding conductor but it was in many (not all) cases safer than no equipment grounding conductor at all. A few code cycles (the code is revised every three years) this exception for separate equipment grounding conductors was removed and now ALL equipment (with a few exceptions but not laundry equipment) is required to have a separate equipment grounding conductor. Since there are so many residences that still have the previously approved receptacle with only three wires the NEC allows for new equipment to be field-modified (three wire cordset) to be usable on the older standard. The NEC DOES require that any modifications to the old three-wire circuits MUST bring the circuit into compliance with the current code.

Now, the purpose of the equipment grounding conductor is solely that of safety. The equipment grounding conductor plays no part in the normal operation of the equipment. It exists ONLY to provide a low impedance (low resistance) path back to the source of power for the sole purpose of causing a high current flow (short circuit) to trip the overcurrent protective device (OCPD) i.e. the circuit breaker or fuse. This will occur ONLY when there is a fault in the equipment that causes one of the "hot" conductors to accidentally come into contact with the frame of the equipment. If the equipment grounding conductor is not present then a hot conductor coming into contact with the frame of the machine would cause the frame to become energized and if a person were to to touch the frame and also touch a "grounded" object such as a metal faucet connected to a metallic piping system the electricity could travel through the person shocking, or ultimately killing, the person.

Since the neutral conductor is effectively connected to all metallic plumbing and also to earth ground at the source (the service panel with the circuit breakers or fuses) the neutral conductor is theoretically at ground potential and can function in a manner similar to the equipment ground under certain conditions. Unfortunately, the conditions are seldom such as to preclude other dangers and so the real-world effect of using the neutral as the equipment grounding conductor actually raises the possibility of electrical shock and even death. That is why the code was changed and if not for the huge economic expense in retrofitting all existing installations no exception would be allowed.

Does this help in understanding?
 
  #12  
Old 04-14-11, 11:28 AM
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hi guys Ė

Donít know much at all electrical. But if mimino has a ground wire in the cable to his receptacle box (i.e., 10-3 with ground) couldnít he just switch to a 4-prong receptacle? In other words if possible isnít it better to upgrade the receptacle?

I had many receptacles with no ground but the cable had a ground wire that was actually connected to the receptacle box. I just changed the receptacles to one with ground.

Maybe itís unusual to have a ground wire in the cabling to ungrounded receptacles and I was lucky Ė but that was my case anyway. And I guess mimino already bought the 3-wire cord anyway.
 
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Old 04-14-11, 01:35 PM
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I'd say 8 times out of 10, an old 3-wire receptacle is going to be wired either with ungrounded Romex, or SE (service entrance) cable which has only two wires plus a bare neutral (the code loophole which made use of SE cable advantageous has since been closed). Neither are permitted to be changed to a 4-prong system. The only way is if there is an actual ground wire in the Romex that is connected at the panel, or if the circuit was run using armored cable or conduit that is properly terminated and electrically continuous to the panel.

Unfortunately what you did with the receptacles could be dangerous. Just because there is a ground wire connected to the box doesn't always mean it is continuous throughout the system or connected at the panel. You have to test before you do that.
 
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Old 04-14-11, 06:35 PM
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ALOT of dryers in my area are 10-3G with a 3-wire receptacle. Why not a 4-wire, I dunno.
 
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Old 04-14-11, 07:19 PM
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Justin, alot is not a word. :NO NO NO:

My house, built in 1987, has 10-3 w/g type NM cable to the dryer receptacle yet a 3-wire receptacle. I should have changed it before the laundry set was delivered but in my particular case it doesn't matter as my laundry set is a straight 240 volt set.
 
  #16  
Old 04-14-11, 07:30 PM
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def. a good read, Furd!

hooked it up like you said: green wire to the neutral terminal. seems to work like it did before
 
  #17  
Old 04-14-11, 08:32 PM
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Originally Posted by JerseyMatt View Post
...
Unfortunately what you did with the receptacles could be dangerous. Just because there is a ground wire connected to the box doesn't always mean it is continuous throughout the system or connected at the panel. You have to test before you do that.

...
Hi Matt. I did first follow the cables back to the breaker panel and it looked like the ground wire was connected there also. I was really surprised. After I switched in new receptacles I also used one of those 3- prong testers that you plug into the receptacle and it showed it was grounded. But i'm not sure if that was really good enough?

I think it is all original wiring from the 1960's. The receptacles look like those old fashioned kind. Why would they go through the trouble and expense and then finish by putting in ungrounded receptacles ?
 
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Old 04-14-11, 09:01 PM
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They probably didn't use the four-wire receptacles at the time because they simply weren't that common. I suspect that is why my house has a three-wire receptacle although it has the four-wire (bare ground, insulated neutral) cable.
 
  #19  
Old 04-15-11, 07:19 AM
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hey, guys! i've posted this question on 2 forums at the same time, and now the people from the other forum telling me that what you've suggested is not right, and that i should unhook that green wire from the neutral terminal and hook it back up to that screw, then add a neutral strap to the neutral terminal going to the other green screw. i'm lost: 3 Wire (washer/dryer) Configuration Question - Electrical - DIY Chatroom - DIY Home Improvement Forum
 
  #20  
Old 04-15-11, 09:53 AM
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Originally Posted by Furd View Post
They probably didn't use the four-wire receptacles at the time because they simply weren't that common. I suspect that is why my house has a three-wire receptacle although it has the four-wire (bare ground, insulated neutral) cable.
Gotcha Furd!

That explains it! Thanks.
 
  #21  
Old 04-15-11, 01:24 PM
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4-wire to 3-wire, not the other way around

Actually, you CAN adapt from a 4-wire plug, but not vice versa. Here's an example of an L14-30P to L6-30R plug adapter , but you just wouldn't be able to convert the opposite-- from an L6-30P (3-wire) to L14-30R (4-wire)
 
  #22  
Old 04-15-11, 03:02 PM
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Originally Posted by mimino View Post
hey, guys! i've posted this question on 2 forums at the same time, and now the people from the other forum telling me that what you've suggested is not right, and that i should unhook that green wire from the neutral terminal and hook it back up to that screw, then add a neutral strap to the neutral terminal going to the other green screw. i'm lost: 3 Wire (washer/dryer) Configuration Question - Electrical - DIY Chatroom - DIY Home Improvement Forum
Quite honestly, you can put the pigtail back on the cabinet screw and then put an additional pigtail between the neutral connection and the other cabinet screw if you want to be doubly sure. I don't think that is necessary but it won't hurt anything. It will absolutely and positively ground the cabinet and whatever that existing green pigtail goes to (I'll bet that somewhere in the wiring harness it goes back to the cabinet) to the neutral.
 
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Old 04-15-11, 07:18 PM
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Originally Posted by Ck1978 View Post
Actually, you CAN adapt from a 4-wire plug, but not vice versa. Here's an example of an L14-30P to L6-30R plug adapter , but you just wouldn't be able to convert the opposite-- from an L6-30P (3-wire) to L14-30R (4-wire)
Wow! That's a lot of bucks for that. Guess you're paying for tooling etc. for an unusual item.
 
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Old 04-15-11, 07:33 PM
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Guys, that's a twist lock.
 
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Old 04-15-11, 07:43 PM
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They're only replacement connectors, you could diy for alot cheaper.
 
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Old 04-16-11, 07:52 AM
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Originally Posted by Ck1978 View Post
Actually, you CAN adapt from a 4-wire plug, but not vice versa. Here's an example of an L14-30P to L6-30R plug adapter , but you just wouldn't be able to convert the opposite-- from an L6-30P (3-wire) to L14-30R (4-wire)
Notice that the components of the adapter are U.L. Listed, but the assembly isn't. Under certain circumstances a 4-wire dryer can be run on a 3-wire circuit and still be code compliant, but no other appliance that I am aware of is allowed to be run this way (30 amp). Not that it wouldn't work, but it would be a code violation for most appliances.
 
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Old 04-16-11, 11:19 AM
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Originally Posted by CasualJoe View Post
Notice that the components of the adapter are U.L. Listed, but the assembly isn't. Under certain circumstances a 4-wire dryer can be run on a 3-wire circuit and still be code compliant, but no other appliance that I am aware of is allowed to be run this way (30 amp). Not that it wouldn't work, but it would be a code violation for most appliances.
As Ray said, that's not a dryer plug, it's twist lock. And if you look carefully, running a 120/240v device like a dryer through an adapter like this would be dangerous, because it's removing the neutral and would cause the ground to be used as a current path. Its design is for plugging a grounded straight 240v device into a grounded 120/240v receptacle.

And under grandfathering, ANY dryer or stove can be run on a 3 wire circuit, as long as the existing 3 wire receptacle is not tampered with. You simply install a 3 wire pigtail and ground strap on the appliance and it meets code. I don't know why you say it would be a violation.. What isn't allowed is to change the RECEPTACLE to 4 wire if there is no grounding conductor, or to change the receptacle to 3 wire if a 4 wire is already in place..
 
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Old 04-16-11, 08:41 PM
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ANY dryer or stove can be run on a 3 wire circuit, as long as the existing 3 wire receptacle is not tampered with. You simply install a 3 wire pigtail and ground strap on the appliance and it meets code
Agree

What isn't allowed is to change the RECEPTACLE to 4 wire if there is no grounding conductor, or to change the receptacle to 3 wire if a 4 wire is already in place..
Also agree

I don't know why you say it would be a violation
Read what I said again, I think we agree here. I said no other (30 amp 4-wire) appliance (other than a dryer) that I am aware of can be run from a 3-wire circuit without it being a code violation.
 
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Old 05-20-11, 10:23 AM
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just update, i've added the extra strap (wire), and so far so good
 
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