ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades New Zealand is an interesting place

Until the mid-90's, American hair dryers were double insulated (2-prong plugs). Then the standard was changed, hair dryers removed from the market, and new units offered with 3-prong plugs mounted on these massive "wall wart" type "Immersion detection current interrupters."

As best I can tell, the ground prong only serves to let the test function of the detector work.

Joe Tedesco once had a thread at this forum, where he showed such a 'detector' equipped hair dryer happily running while floating in a sink full of water.

Keep in mind that US codes REQUIRE a 20-amp 120-volt receptacle in the bath, near the sink. This is quite the opposite to other places, many of which either ban any receptacles in the bathroom, or severely limit their available power.

A "loop circuit" is powered from BOTH ends. The wire goes from panel to the receptacles and back to the hot side of the panel again. You have to interrupt power to both sides of the loop to remove power from the circuit. This is NOT what we use in the US.

The Immersion detector is a special purpose GFCI that incorporates a ring in the discharge chute which is connected to the ground in the plug, so that video Joe has was before the immersion detector.
If any current flows in that ring circuit, the GFCI is unbalanced and the detector trips.
As has been pointed out before, the simple GFCI might not trip if there is no ground path in the sink.

Great to hear that you had a good time in NZ.
Yes our electrical systems are a bit different then in the USA.
Single pole switching because we use the MEN system here
( Multiple Earth Neutral )
Never heard of a fire alarm tamper detector in a motel MCB board as these devices are supposed to be separately wired from 240 Volts mains wiring.
A heat or smoke detector may be located nearby.
We still use the old English colours for fixed TPS house wiring.
Red (Phase) Black (Neutral) and Green or Yellow Green (Earth).
For flex leads we use Brown (Phase) LightBlue (Neutral) GreenYellow (Earth)

I did see another interesting thing
You guys use something that looks like Smurf tube (type ENT), outside. That is dry only here.

Umm, no it isn't, John.
Texas-Ranger, described the loop circuit above, what you're thinking of is a RING circuit, where the phase wire at each end of the circuit is fed by the same fuse/CB and each plug in the circuit has a lower rated fuse installed in it, to protect the connected appliance.

Greg, that looks like either a plumber or an apprentice installed that.
That stuff is known as Bettaflex here, or flexible medium-duty PVC conduit.
It's used by people that can't use a bending spring on rigid PVC conduit.
Reason I say a plumber may have been involved is that that saddle to the right of the socket-outlet is a pipe saddle made for 3/4" pressure pipe, which is bigger than 20mm conduit.

Well this is in the food court on "Eat Street" in Rotorua if you want to go get them.

I stand corrected .... It's too easy to thing of "loop" and "ring" as having the same meaning!

(Indeed, downtown Chicago has a ring of elevated train track completely around it; hence, the downtown area is known as "The Loop.")

All the hair dryers I've seen have 2 prong plugs on the immersion detectors. They can be plugged into either a 2 or 3 wire receptacle

Joe T's hair dryer just had about 90 seconds of a hair dryer in a sink full of water, with no comments.

Mike Holt has a video on the same subject with in detail explanations of the theory behind why it didn't trip the GFI.

https://www.youtube.com/watch?v=kioaW9yEjYI

In short, the water had no reference to ground. If he'd have touched the water, and come into contact with a grounded surface, the GFI would have tripped.

The pipe looks familiar, the type of installation not really. Usually cable would be used under such circumstances and the conduit would only serve as sleeving with open bends to provide minimal added protection and mainly mechanical fastening. If I remember it I'll take a picture of the wiring in our cellar, which is pretty typical of such rooms.

Occasionally you see that type of light grey rigid conduit used outdoors in direct sunlight. Usually it's all bowed downwards in horizontal runs and cracked all over. Cable has to be UV resistant too but most people don't seem to care at all.

I don't think anyone used a bending spring here from the mid-70s onwards. They're still in manufacturer's catalogues but I haven't seen them for sale anywhere, only for copper plumbing pipes.