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#41577 - 08/31/04 08:48 AM Rangs/Dryer plugs 3 and 4 prong
aldav53 Offline
Member
Registered: 08/22/01
Posts: 545
Loc: Chandler, AZ USA
They are gradually converting over to 4 prong plugs for electric ranges and dryers. Not much good on the older 2 wire with ground circuits. Is the the new code requiring all 3 wire with ground circuits be run?
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#41578 - 08/31/04 08:57 AM Re: Rangs/Dryer plugs 3 and 4 prong
CTwireman Offline
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Registered: 02/07/02
Posts: 840
Loc: Connecticut, USA
What code edition are you using in AZ? The change to 4 wire was first required in the 1996 NEC, so this isn't exactly new.

To answer your question, from the 1996 NEC on requires 4 wire circuits in all new installations. Old 3 wire circuits are permitted to remain.

A feed to a dryer or range that is 2-wire with a bare ground has always been a code violation, and should be replaced no matter what.

Peter

[This message has been edited by CTwireman (edited 08-31-2004).]
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#41579 - 08/31/04 08:59 AM Re: Rangs/Dryer plugs 3 and 4 prong
Bill Addiss Offline
Member
Registered: 10/07/00
Posts: 3875
Loc: NY, USA
Al,

Yes, all new Electric Range and Dryer circuits installed must be 4 wire. This does not mean that older 3 wire (that were code-compliant) circuits must be replaced.

Bill
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#41580 - 08/31/04 09:01 AM Re: Rangs/Dryer plugs 3 and 4 prong
Bill Addiss Offline
Member
Registered: 10/07/00
Posts: 3875
Loc: NY, USA
Peter,

sorry, I didn't see your reply.


Bill
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#41581 - 08/31/04 09:45 PM Re: Rangs/Dryer plugs 3 and 4 prong
aldav53 Offline
Member
Registered: 08/22/01
Posts: 545
Loc: Chandler, AZ USA
Peter, if older 2 wire circuits were a code violation, then how would they be wired to an older 3 prong plug with 2 hots and a center ground? Which is what was used everywhere.
The center conductor (ground) was used as a current carring neutral for any 120 volt on the dryer.
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#41582 - 08/31/04 10:03 PM Re: Rangs/Dryer plugs 3 and 4 prong
caselec Offline
Member
Registered: 04/14/02
Posts: 558
Loc: San Jose, CA
Older 3-wire range (10-50) and dryer (10-30) receptacles have 2 hots and a neutral but no equipment ground. The neutral was used to ground the non current carrying metal parts of the appliance. As Peter said it has never been code compliant to use an equipment ground as the neutral.

Curt
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#41583 - 08/31/04 11:16 PM Re: Rangs/Dryer plugs 3 and 4 prong
e57 Offline
Member
Registered: 05/27/03
Posts: 2876
Loc: S.F.,CA USA
Anyone ever notice that new ranges and dryers are sold without a cord... And instructions for installing both a 3 and a 4 wire cord?

A few times "Appliance Installers" have shown up with only 3-wire cords. (Look at me funny as I explain it too them.)And try to get me to change the receptical to fit thier 3-wire cord.
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#41584 - 09/01/04 03:46 AM Re: Rangs/Dryer plugs 3 and 4 prong
Speedy Petey Offline
Member
Registered: 08/29/03
Posts: 173
Loc: Upstate, NY
if older 2 wire circuits were a code violation, then how would they be wired to an older 3 prong plug with 2 hots and a center ground?
It was done because people who didn't know what they were doing wired them. Unfortunately this does happen.

Which is what was used everywhere
Just because it was done everywhere doesn't mean it was ever legal.

The center conductor (ground) was used as a current carring neutral for any 120 volt on the dryer.
Again, never was code and is one of the more dangerous mistakes made. Especially with a large metal box usually associated with water.
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#41585 - 09/01/04 04:58 AM Re: Rangs/Dryer plugs 3 and 4 prong
winnie Offline
Member
Registered: 09/15/03
Posts: 649
Loc: boston, ma
I believe that there a bit of confusion.

For large 240V appliances (ranges and dryers), old code permitted the use of the use of the same conductor for both grounding the frame and neutral return of 120V loads. This is _not_ necessarily a violation.

I don't know the details of older code, but in the 2002 code, there are specific descriptions of when such a circuit make be continued to be used. In particular, the ground/neutral wire must either be insulated, or the cable must be service entrance cable. Type NM with two insulated conductors and a bare ground would be explicitly prohibited. But if the install was done using Type MC cable with an insulated ground, then my read says that it can still be used.

All _new_ installs must correctly separate ground and neutral.

I don't see how it could ever be appropriate to connect a three conductor cable to a 4 slot receptacle. Ground and neutral would be shared, but this would be hidden back in the wall.

-Jon
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#41586 - 09/01/04 05:35 AM Re: Rangs/Dryer plugs 3 and 4 prong
electricman2 Offline
Member
Registered: 11/09/03
Posts: 269
Loc: Thomasville, NC USA
Anybody want to speculate how many dryers are out there supplied with 10-2 romex? I have seen a few.
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