Question about new wire for washer/dryer combo: What do I need?

[hj]

quote; a) The electrical code was changed probably 20 years? ago to not allow the 3 prong connection.

Maybe so, but my house built 12 years ago has the three prong receptacle.

[hj]

quote; then what has happened is the metal water pipe is just energized and should a plumber have to repair the metal water pipe we have just put him in danger.

That would only occur if there were an additional problem in the system, such as a failed neutral in the utility's feed. Then, the piping would function as the neutral UNTIL the plumber "broke" the continuity. I had it happen many times years ago. In Chicago, when we separated a water line, we NEVER used our hands. We hit the pipe with a wrench to see if there was a spark between the two pieces. One time, everything in the house that was turned on burned out when I disconnected the water line to the water heater. I have also been walking through a house, or in one case UP TO THE TRAILER, when my TicTracer went off indicating that some metal object was energized. Usually, the occupants did not know of the hazard because they could not touch the object and a "ground source" at the same time.

[leejosepho]

I no longer recall the details or where, but I have seen "bonding wires" or whatever across unions and such ... and I think I first saw that in the Navy.

[jimbo]

quote; a) The electrical code was changed probably 20 years? ago to not allow the 3 prong connection.

Maybe so, but my house built 12 years ago has the three prong receptacle.

I am surprised....but maybe Speedey or someone can bring us up to speed on the code situation.

[jwelectric]

That would only occur if there were an additional problem in the system, such as a failed neutral in the utility's feed.

If the piping was metal to the point of entry and there was nonmetallic underground supplying the building then the open neutral somewhere else would not affect the metal pipes in the building, but, the bond to the metal pipe from an appliance if the metal pipe was bonded to the service as required by 250.104 there would be a parallel path between the neutral of the appliance and the water pipe.

Should the metal water pipe be broke then the two sections would be at different potentials and a shock hazard would be present for anyone touching the two pieces of pipe.
One path from the appliance frame that has a three wire connection, on the neutral to the service. The second parallel path from the appliance through the bonding jumper to the metal pipe down the metal pipe to the required bonding to the service.

Getting between the water pipe would be the same thing as getting between the neutral conductor as both are a parallel path from the appliance back to the service equipment.

[jwelectric]

I am surprised....but maybe Speedey or someone can bring us up to speed on the code situation.

During the 1990 cycle 250-60 read;
Frames of Ranges and Clothes Dryer. Frames of electric ranges, wall-mounted ovens, counter-mounted cooking units, clothes dryers…………….

In the 1996 cycle 250-60 read
Frames of Ranges and Clothes Dryers. This section shall apply to existing branch circuit installations only.

In all the cycles the allowance to use the neutral as the equipment grounding conductor the conductor had to be insulated or part of SE cable and land in the service equipment.