Well, here is what I came across: this was way up in a forest reserve, where the Feds had permitted about four homes to be built. It all had one transformer.
The conduit coming out of the panel (ridged galvenized) that ran under ground to a sub panel in an out building was HOT (almost enough to raise a blister) at the nipple that tied it to the panel case.
I take that to mean that the path to ground here was going thru that conduit, rather then the driven ground that was a few feet away.
I installed an additional driven ground and the problem went away. At least, nothing was hot enough to burn me.
So some current was traveling to ground, it seems to me.
The theory of current flow is no different for our homes or our flashlights. There must be a path from the positive to the negative of the batteries or the flashlight will not work. The same is true for our systems in our homes. There must be a path from the transformer back to the transformer not to the ground rod.
In section 250.4(A)(1) we are told why we connect to earth. There are four reasons and four reasons only. Neither one of these four reasons is to let current run to earth.
250.4 General Requirements for Grounding and Bonding.
The following general requirements identify what grounding and bonding of electrical systems are required to accomplish. The prescriptive methods contained in Article 250 shall be followed to comply with the performance requirements of this section.
(A) Grounded Systems.
(1) Electrical System Grounding. Electrical systems that are grounded
shall be connected to earth in a manner that will limit the voltage imposed by lightning, line surges, or unintentional contact with higher-voltage lines and that will stabilize the voltage to earth during normal operation.
The commentary
Section 250.4 provides the performance requirements for grounding and bonding of electrical systems and equipment. Performance-based requirements provide an overall objective without stating the specifics for accomplishing that objective. The first paragraph of 250.4 indicates that the performance objectives stated in 250.4(A) for grounded systems and in 250.4(B) for ungrounded systems are accomplished by complying with the prescriptive requirements found in the rest of Article 250.
The requirements of 250.4 do not provide a specific rule for the sizing or connection of grounding conductors; rather, it states overall performance considerations for grounding conductors and applies to both grounded and ungrounded systems.
Without more information I cannot tell you why that extra rod caused the heat to go away but I can promise it wasn’t because the earth ate it.
Edited to add;
My brain is like the joints of my body, when I first get up in the mornings it takes a while before they start working properly.
When you touched that pipe if it was current flowing on the pipe that made it feel warm then you would have felt more than warm, you would have felt the current also. This is enough to say that it wasn’t current that was causing the pipe to feel warm.
During the heat of summer I have picked up pipe that I wanted to turn loose of in a hurry that hadn’t been installed yet. Could this have been the problem?