Question that bothers me. After 50 years of allowing the neutral feeding a dryer and range receptacle to serve as the ground also is now required to be independent. As we change the cords on existing units we separate the ground from the neutral and install the cord to be used with a 4 wire receptacle. Problem? I am betting that as these units get older and folks start to sell them the people that pick them up will live in older properties with 3 wire receptacles. Their answer to problem? Take the 3 wire cord from their appliance and install it in place of the 4 wire cord on the used appliance w/o knowing the situation they are creating. Within 10 years we have loads of dryers and ranges not grounded and the potential for lethal shock. Am I missing something or did the code panel miss something that should have been left in place, expecially with todays copper prices? I have already come across this situation where the girls father thought he was doing her a favor and left the unit ungrounded.Just a thought.
Ron

I agree with your analogy and it's going to happen. But we have this going on daily when people move into a home with the old 2 wire system and they need to plug in an appliance and the cap has a two wire with ground. Simple solution- just use one of those 2 wire to three wire adaptors you can buy at any hardware store. No one ever pursues the connection of the equipment grounding conductor. Boils down to the saying " You can protect the fool but you can't protect the damn fool."

[This message has been edited by George Little (edited 10-25-2004).]

I never understood why a dryer had a 120v load in the first place. The motors are special items that only work in dryers anyway, to say this is all over light bulbs is ridiculous. Those bulbs are not usually standard "appliance bulbs" either.

My pet peeve is that the 4-wire receptacles will not fit into a single gang mud ring- which makes a changeover problematic.
What I'd love to see is a combo "super size" box that would hold a duplex dryer receptacle- one 3-wire, one 4.

A Cooper/Eagle will fit in a single gang box.

The American housewife would not put up with not having a light in her dryer and 240 bulbs are not a practical solution in a world where every other bulb is 120. Also, in the era before electronic controls, 120 volt timer motors were much more available and cheaper. Given that residential wiring is set up that way, 120 loads acually make sense.

If you are whirlpool or maytag making 100,000 dryers a year the manufacturer will make you whatever timer you spec and the price wouldn't be any different. They used those little Synchron motors in computers all those years and they were 240. U/L could have made this stick 50 years ago and there would be also 240v appliance bulbs at the grocery store for stoves and dryers.
We simply lived with the exception too long and nobody was willing to do anything about it.

Sounds like going to metric doesn't it?

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Charlie Eldridge, Indianapolis, Utility Power Guy

Hey John I actually did that. PLaced a double gang box in a apartment for a guy.That way he can wire to what ever style dryer comes in. I also always install dryer and range repts in a double gang box just for convience saves install time and much easier.

The basic principle of safety engineering is that is should take two failures to cause a danger to humans. The three wire dryer and range circuits violate that principle. Any failure of the neutral of the three wire dryer and range circuits causes the 120 volt control and motor voltage to appear on the shell of the appliance. With a four wire circuit if the neutral goes open the appliance stops working. In order for the shell to become energized in that event the neutral has to fault to ground and the Equipment Grounding Conductor has to go open. The change to separate EGCs on these circuits is just sound practice. The minor increase in cost does not justify continuing the dangerous practice of the past.
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Tom H

gfretwell,

On the reasoning for 120/240V service to clothes dryers—they used to have labels showing operation on 120/240V OR 120V only. At 120V, the 240V 4500W heater would work at only ~1100W, but it was intended to as needed.

The remote possibility that someone might hook a dryer to 120v certainly does not justify 50 years of this violation. It doesn't address the 6-30 plug at all. The easiest "fix" would have been a U/L listing change in the Eisenhower or Truman administration.

gfretwell, read the original post once again. You did not understand what it said. Of course this situation would have best been corrected 50 years ago but as the post states, we will be seeing the hazardous situation increasing as the 4 wire corded dryers and ranges (used)are purchased by the uninformed and the cords are changed to the 3 wire cord they have in the rental unit they live in. Now the ground is missing and subject to having the case energised. And it is not by a remote chance. I am seeing it more and more. Would be nice if a large orange sticker would be attached to the back of the ranges and dryers warning that installing a 3 wire cord could produce a shock hazard. Might be a good suggestion to the manuf.
Ron

I know what started thwe thread but if U/L had simply made dryers be pure 240v loads we wouldn't have the 4 prong plug in the first place. When you figure dryers get replaced every 10 years or so and the receptacle goes on forever it looks like we solved the problem from the wrong end of the cord.

Actually, the cost differences do exist. It is slightly cheaper to wind a coil with fewer turns of heavier wire. In large quantities, those differences add up. My dad had a friend who worked at Ford and he said the auditors would happily cut your throat for a nickel a unit. An appliance manufacturer would do the same for far less.
Now, you can add to a standard and improve it but flat out changing one usually doesn't work. If the dryers just have a simple diagram in the box where the cord is terminated showintg the proper way to wire for both types of cord, there should be no great problem.

How much do you figure it costs the dryer and range business to maintain 2 cord standards?
If they had spent half as much retrofitting their dryers for 240v operation as they did lobbying NFPA to maintain their exception they would have been money ahead by the time LBJ took office.
I think it was Phil Simmonds who pointed out the war was over 30 years ago.

I think that would be a NEMA issue, not a UL issue.