In the case of Multiple GFCI’s on the same circuit, besides being incorrectly installed according to the UL listing, is this a potential hazard or just redundant? If it is a hazard, what is the potential hazard?
(Bottom line: does this increase or create a risk of electric shock?)
(Also, feel free to reference another thread if this has been discussed before. Couldn’t find it.)
No hazard. A big pain in backside though… Although you say on same circuit… when you mean on same circuit, you mean one wired after the other - as the second is wired to the load side of the first, or simply on same over current protection/breaker.
Can you provide a reference on this UL listing? I doubt that there is.
There is no potential hazard or redundancy if they are wired correctly.
If done correctly and the GFCI’s are not defective then there would be no increase in risk of electric shock.
The above is just my opinion. 
Edit:
If wired correctly having multiple GFCI’s on the same circuit will add convenience to the home owner. They won’t have to go to the other end of the home to reset the tripped receptacle.
Roy,
That thread doesn’t answer the question or concerns of the OP.
That’s what I mean–wired one after the other. First one trips normally and kills the second. Second one trips both but makes a rapidly repeating clicking noise when using test button on 3-light tester (many clicks when pressed for one second) and gives reading of “Hot & Ground Reverse” after tripping. Which I’m pretty sure is a hazard in this case because the outlet still has power…
They are both at the kitchen counter on opposite sides of the sink.
What you described is improperly wired GFI receptacles.
At least that’s what it sounds like, because what you’re saying is a little confusing.
“Second one** trips** both” “reading of Hot & Ground Reverse”** after tripping**", “outlet still has power” ???
Yeah, you’re right. Weird thing was it worked one way but not the other.
You’re right. Weird thing is it works one way but not the other.
Sounds like the down stream receptacle(s) are wired incorrectly.
I am trying to think how wired to cause this. Have to go out to shop and wire some up and play to see if I can duplicate it. I can see how the first would kill both, if second is wired on load side of first. If a fault were placed on second one, it should trip - am not certain what would happen to first which is why I want to play a bit. However, once tripped, there should be no voltage present once tripped. At this point I am not sure what to say, will try to duplicate tonight. But without further details, would suggest it be checked based upon what you state as observations.
I reported it as improperly wired and recommended a licensed electrician for further evaluation and estimation of the cost of repairs.
GFCIs will also fail if you wire them improperly."The most important thing to remember when wiring them is to connect the wire originating at the breaker to the line side of the GFCI and the wire connecting downstream to the load side of the device.
The GFCI terminals are clearly marked “Line” and “Load.” As an added safety improvement, one manufacturer markets a 15A, 125V receptacle with a built-in line-load reversal feature that prevents the GFCI from resetting if the installer mistakenly reverses the load and line connections."
Since around 2003 GFCI receptacles are designed to not operate if reverse wired as part of an updated UL standard.