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4 wire Dryers #76225
01/07/01 12:56 AM
01/07/01 12:56 AM
Bill Addiss  Offline OP
Member
Joined: Oct 2000
Posts: 3,902
NY, USA
I've noticed a bit of confusion lately with new requirements for 4 wire dryer circuits.

#1 a Store employee told a customer that was looking for a dryer outlet that He had to install a 4 wire receptacle (& cord/plug) even though He only had a 3 wire cable there now. - "Just put a Jumper" (I made a point to correct him)

#2 I've had the task of installing several 4 wire dryers recently and noticed that the labels on the Appliances give instructions on where to connect the 4 wires (including ground) but do not inform you that the Factory-Installed bond from neutral to frame has to be severed. Only after digging into the manual did I find a Fuzzy description of what had to be done. (Bad picture too!)

Has anyone else noticed this?

2017 / 2014 NEC & Related Books and Study Guides
Re: 4 wire Dryers #76226
01/07/01 08:30 AM
01/07/01 08:30 AM
S
sparky  Offline
Member
Joined: Oct 2000
Posts: 5,360
A lot of sparky's are getting into it with appliance peddlers, most of whom are not versed in the NEC,yet may suggest, or even install. I find a lot of outdated reference to the old 250-60. [Linked Image]
In trying to explain the need for a 4-prong pigtail, i've been simply pointing out an average receptacle's separation of N & G, as relates to recent code practice concerning dryers, ranges etc. [Linked Image]
One has to have a shred of sympathy for the appliance man here, who has been pedaling 3-prongs forever. [Linked Image]

Re: 4 wire Dryers #76227
01/07/01 12:15 PM
01/07/01 12:15 PM
C
cinkerf  Offline
Member
Joined: Dec 2000
Posts: 84
Pittsburgh, Pennsysvania. ...
I once read an article explaining why the three wire dryer circuit was permitted in the first place. I believe the reason given was shortage of copper. Did anyone else ever hear such a reason?

(Frank) cinkerf

Re: 4 wire Dryers #76228
01/07/01 05:24 PM
01/07/01 05:24 PM
S
sparky  Offline
Member
Joined: Oct 2000
Posts: 5,360
I would imagine any metal was "rationed" during WW2..... [Linked Image]

Re: 4 wire Dryers #76229
01/07/01 11:36 PM
01/07/01 11:36 PM
B
Bennie R. Palmer  Offline
Member
Joined: Nov 2000
Posts: 72
Milwaukie, OR 97267 USA
Until the 50's, equipment grounding was not considered a big deal. Washing machine outlets had 2 wire receptacles. Machines came with a jumper and clamp to connect to the cold water pipe. Electric dryers were treated the same. The problems developed when the appliances were on a concrete floor, and the jumper was not connected. To avoid lawsuits, the manufacturers grounded the neutral to the frame. Many are still in operation. It will be a long time before homes catch up with the four wire connections.
I don't think material shortage had anything to do with the three wire circuit, it was just the thinking at the time, face it, they work, and don't appear to be a problem, other than the discomfort of the customer, when the plug won't fit.
My personal opinion is; There was nothing dangerous with the three wire connection, and it should have been left alone.

Re: 4 wire Dryers #76230
01/08/01 09:32 AM
01/08/01 09:32 AM
C
cinkerf  Offline
Member
Joined: Dec 2000
Posts: 84
Pittsburgh, Pennsysvania. ...
Bennie,
Thank you for clarification.
(Frank) cinkerf

Re: 4 wire Dryers #76231
01/08/01 10:50 AM
01/08/01 10:50 AM
sparky66wv  Offline
Member
Joined: Nov 2000
Posts: 2,236
West Virginia
Okay... Im confused...

Wouldn't bonding the frame of a clothes dryer to the neutral on a three-wire be similar to bonding the Green Screw of a 125V receptacle to the neutral on an old two-wire circuit to achieve a "grounded" plug?

I don't see the difference especially considering that most, if not all dryer motors run on 120V, unbalancing the loads a significant amount. So either I'm missing something here...or...?

I've been known to insist upon four-wire installations if I have my name associated with it, am I justified in this thinking? Or have I been "just hard to get along with"?

Thanks for your comments, and don't be afraid to correct me! I'm always learning...


-Virgil
Residential/Commercial Inspector
5 Star Inspections
Member IAEI
Re: 4 wire Dryers #76232
01/08/01 11:22 AM
01/08/01 11:22 AM
Bill Addiss  Offline OP
Member
Joined: Oct 2000
Posts: 3,902
NY, USA
Good question -

I'm also interested in hearing the reason why a 3 conductor SE cable (2 insulated 1 bare) was allowed for a 3 wire Dryer installation and not a 10/2 Romex w/gr

Bill

Re: 4 wire Dryers #76233
01/08/01 06:56 PM
01/08/01 06:56 PM
Tom  Offline
Member
Joined: Jan 2001
Posts: 1,044
Shinnston, WV USA
I heard exactly the same rumor about the copper shortage in WW2 & I believe that is the reason that the 3 wire installation was allowed. As a side note, the Manhattan Project would have used so much copper for transformers that it would have actually hurt the war effort. The treasury ponied up several million ounces of silver which was made into wire for the required transformers.

As Bennie pointed out, the 3 wire installation has had an excellant safety record. However, the jacklegs in this business started to think that neutrals (wahatever they are) and equipment grounds were interchangeable. I think it is best that we have now gone to a 4 wire installation.

Tom


Few things are harder to put up with than the annoyance of a good example.
Re: 4 wire Dryers #76234
01/09/01 01:13 PM
01/09/01 01:13 PM
B
Bennie R. Palmer  Offline
Member
Joined: Nov 2000
Posts: 72
Milwaukie, OR 97267 USA
My concern regarding the change, is it is too little too late. There is many more older homes than new ones. Homes far outlast the appliance.
Homeowners will often change the attachment cord to a three wire, now there is no ground at all. Should they change the receptacle to a four wire, they do not have the fourth wire, again, no ground at all. This is not increasing safety. Very bad decision, in my opinion. It was not broke until the fix was in.

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