Don I want to apologize for this post as after reading it a couple of times I can see where it doesn’t sound so good so let me go into a little more detail which I sometimes don’t do. Sometimes when I am in a hurry I state things in a short sentence and what I am trying to say just don’t come out right.
In every manufacturer’s installation guide published it will always say to make the installation according to any and all local codes. This will include the NEC if it is adopted in your area.
Here is the section of the NEC which addresses the three wire receptacle for ranges and dryers;
250.142 Use of Grounded Circuit Conductor for Grounding Equipment.
(A) Supply-Side Equipment. A grounded circuit conductor shall be permitted to ground non–current-carrying metal parts of equipment, raceways, and other enclosures at any of the following locations:
(1) On the supply side or within the enclosure of the ac service-disconnecting means
(2) On the supply side or within the enclosure of the main disconnecting means for separate buildings as provided in 250.32(B)
(3) On the supply side or within the enclosure of the main disconnecting means or overcurrent devices of a separately derived system where permitted by 250.30(A)(1)
(B) Load-Side Equipment. Except as permitted in 250.30(A)(1) and 250.32(B) Exception, 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 on the load side of a separately derived system 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 ovens, counter-mounted cooking units, and clothes dryers under the conditions permitted for existing installations by 250.140 shall be permitted to be connected to the grounded circuit conductor.
250.140 Frames of Ranges and Clothes Dryers.
Frames of electric ranges, wall-mounted ovens, counter-mounted cooking units, clothes dryers, and outlet or junction boxes that are part of the circuit for these appliances shall be connected to the equipment grounding conductor in the manner specified by 250.134 or 250.138.
Exception: For existing branch-circuit installations only where an equipment grounding conductor is not present in the outlet or junction box, the frames of electric ranges, wall-mounted ovens, counter-mounted cooking units, clothes dryers, and outlet or junction boxes that are part of the circuit for these appliances shall be permitted to be connected to the grounded circuit conductor if all the following conditions are met.
(1) The supply circuit is 120/240-volt, single-phase, 3-wire; or 208Y/120-volt derived from a 3-phase, 4-wire, wye-connected system.
(2) The grounded conductor is not smaller than 10 AWG copper or 8 AWG aluminum.
(3) The grounded conductor is insulated, or the grounded conductor is uninsulated and part of a Type SE service-entrance cable and the branch circuit originates at the service equipment.
(4) Grounding contacts of receptacles furnished as part of the equipment are bonded to the equipment.
This is was what I was aiming for when I made the remark to read the entire manual instead of just looking at the pictures. Most people do what they see in the manual and ignore the reference to make the installation according to any local codes simply because they don’t know the local codes so all they have to go on is the pictures in the manual.
This is what led to the comment about the lack of knowledge.
I promise that it wasn’t meant to be rude or insulting although after going back and reading the post again I can see where it could be taken that way.
The NEC is a minimum safety standard. To do anything less will result in a system that is unsafe no matter if any of us agree or not. The NEC has been around for over a 100 years and is tweaked every three years. The NEC is an ongoing process to ensure the safety of the user of electricity.
Then there is the theory behind electron flow. Knowing and understanding this theory will make understanding why some of the rules are mandated in the NEC a lot easier to comprehend. The old statement of if it works it must be right does not fly when it comes to electrical energy. This cannot be stressed enough for the average Do-It-Yourselfer.
Yes by exception a dryer or range can be installed with a three wire receptacle but there are restrictions when doing so. I would never install a three wire cord to either of these appliances for any reason. If the homeowner could not afford to have the proper circuit installed then I have a hard time understanding how they can afford to buy a new appliance. It is simply because they don’t recognize the danger of a three wire circuit.
Then we have a handful of folks that think installing a wire to the water pipe fixes all this. This is the most ridiculous statement I have ever heard. Doing this puts any fault current on the water pipes and if they are not complete all the way back to the service all we did was hurt the plumber.
No Harm Done Mike.
I have thick skin, Got that from all the RF burns over the years.
Sometimes there is more than 1 Cowboy at the Rodeo.
You and Your Family have a Great New Year.
You are still the best. (well second, Your wife comes first, She put up with you everyday)
Theory only works perfect in a vacuum.