Aldav53, You are correct that the neutral conductor will have current on it. In your original post you were talking about dryer/range receptacles supplied by 2 hots and an equipment ground which is and always has been a non compliant installation.
Read Winnie's (jon's) post, I believe he is correct. Two hots and a bare conductor were legal as long as it was SEC. An old timer told me it was permitted during the 1940's to conserve metal for the war effort. You never know about those old timer stories though. Pat
The bare conductor of type SE cable is approved for use as a neutral conductor. If used as a neutral it must be connected to the neutral buss. The bare conductor of Type NM cable is not approved for use as a neutral conductor. Using the armor of AC cable or a metal raceway for the neutral conductor has never been permitted.
I have also heard that the reason the neutral conductor was permitted to also serve as the EGC was to conserve metal. Some time ago I had a discussion about this with Bennie Palmer and he said that it was not done to conserve metal.
Grounded conductor has to be covered not bare except for se cable. I just had a problem with a dryer I went to troubleshoot. It was a 10/2 feeding the recep & the grounding conductor was used as the 120v potential for the timer loads, Lts. etc; As I had the recep out, I plugged in the dryer & I lost one les and picked up 240v on the other. There is a break in the grounding conductor somewhere. I have to run a 10/3 now & change unit to a 4 prong whip. I'm glad the code wants the noodl & EGC separated.
Doug, my guess is the manufacturer ass-u-me-s that it's automatically going to be going into a house with an old three-wire installation.
If anything, the manufacturer should include both cord-sets and detailed instructions for installing either one depending on what is called for by the end user's situation.
It wouldn't cost the manufacturer THAT much to toss in an extra cordset.