It's the existing wiring that is being grandfathered in & not the dryer or stove, and because so many houses are wired three wire the industry has to support the old standard with three range and dryer wire plugs.
That's true and so there is an exception for dryers and ranges but not for anything else.
Because of this it does not matter what's being plugged into the grandfathered wiring.
It does matter what is plugged in. Article 250.114 "Equipment connected by cord and plug" lists equipment which must be grounded. These are things like refrigerators, freezers, sump pumps, dish washers etc. Furthermore Article 250.142(B) says "Except as permitted by 250.30(A)(1) and 250.32(B), a grounded circuit conductor shall not be used for grounding non-current carrying metal parts of equipment on the load side of the service disconnecting means or the overcurrent devices for a separately derived system not having a main disconnecting means.
"Exception No. 1: The frames of ranges, wall-mounted cooking units and clothes dryers....
"Exception No.2: ...meter enclosures..."
This is also why it is perfectly legal (and safe) to plug you PROPERLY WIRED brew rig into a 3 wire 240V 30 Amp (dryer) or 50 Amp (range) outlet.
Referring to 250.114(4)(f) we find that "cord and plug connected appliances used in damp or wet locations or by persons standing on the ground or metal floors...." are required to be grounded. As one of these brew rigs is not a range, cooking unit, or clothes dryer it would not be legal to ground it with the neutral in an existing 3 wire H/H/N receptacle.
If you can argue that I have misquoted or misinterpreted these sections of the code or find other sections that exempt brew rigs then please site them instead of just saying that it's legal and safe without any supporting evidence.
An interesting twist here is that 250.114(4) pertains to 'other than residential occupancy'. There is no similar requirement in a residential setting (at least in the 2002 version of the code). Seems to me that's an obvious omission because there are damp locations in residences too but I don't write the code. We'll come back to this.
Article 250.118 says "The equipment grounding conductor run with or enclosing the circuit conductors shall be one or more or a combination of the following:
(1) A copper, aluminum...."
Note the key phase "conductor run with or enclosing the circuit conductors". That doesn't mean one of the circuit conductors. A circuit conductor (neutral) can only be used for grounding under the exceptions of 250.142(B).
If you ground your equipment using the neutral you are definitely illegal because you have violated 250.142(B). Again I encourage you to debate this point with supporting arguments rather than blind assertion that it is incorrect. However it seems that you could be legal if you did not ground the equipment at all as this type of equipment is not on the list of things that has to be grounded in a residential setting. Would you want to take this approach? In building such a system you are installing industrial type equipment in a damp location or at least one where liquids have the potential to be thrown about. The fact that you want GFCI protection reflects this. Given this I would think that you would want to consider the spirit of the code and realize that winning the argument is less important than saving your life.
Now why isn't it safe (or as safe as it could be) to use the neutral as the ground source? This has been explained by several people so it's probably a waste of typing to explain it again. In the event of an asymmetrical load or fault (such as contact between wort and one side of a heater) the potential of the neutral will rise above ground or it may already be above ground. In my house it is 100 mV above ground depending on what loads are on. One hundred mV is nothing to worry about when you are standing on a dry floor in rubber soled shoes and touch something connected to the neutral but under wet conditions, skin abrasion etc it could do you in. And of course we're not talking about the nominal offset, were talking about a fault situation where the potential difference is volts. Even so you would probably get away with it 999,999 times out of a million. A disaster is a coincidence of multiple events each of which is by itself very unlikely but given the obvious complexities of the code it should be clear that it there to protect you against these unlikely events.
And proper wiring for one of these outlets is to connect both ground and neutral to the third (white or outside braid) wire!
If you do that and then use the connected wire to ground kettles, your system box etc. you are very clearly in violation of 250.142(B). This has been explained to you before. The fact that you don't accept it either says you don't understand, don't wish to understand or understand but think you know better. I would be concerned about publishing advice which would cause readers to violate the code and do something which is potentially unsafe especially when it is so easy to do it right.
The Home Depot SPA panel is just a convenient way to add a GFCI breaker into the wiring for those who want one.
A spa panel is no more than a sub panel. It is equipped with separate neutral (insulated), and ground busses. They are not to be interconnected unless an isolating transformer of less than 1000 VA capacity is being used.
, here is my take:
![Craft A Brew - Safale S-04 Dry Yeast - Fermentis - English Ale Dry Yeast - For English and American Ales and Hard Apple Ciders - Ingredients for Home Brewing - Beer Making Supplies - [1 Pack]](https://m.media-amazon.com/images/I/41fVGNh6JfL._SL500_.jpg)
