Wanderport Corp (WDRP)

[gharma]

Yep, 8 guage. I was going on the requirement they spec'd for running a branch box for 125 amp load center in the garage. There are a number of aspects of what the NEC specs that have mystified me.
But sure enough, there it is
Voltage 240, Watts 28, 500, Amps AC 120 . . . Wire Size (AWG) 8
for
Temp. Rise @ 1.5 GPM 129.77, Temp. Rise @ 2.5 GPM 77.862, Temp. Rise @ 4.0 GPM 48.6637

I would expect that every electric tankless would have very similar specs in terms of watts needed per degree-GPM deliverable

PS Did you notice this one
http://www.grainger.com/Grainger/EEMAX-Electric-Tankless-Water-Heater-6VEE9?cm_sp=IO-_-IDP-_-RR_VTV70300505&cm_vc=IDPRRZ1

Voltage 120, Watts 3500, Amps AC 29
Now that is not a normal plug-in, but an RV hook-up type plug-in
and it can heat
Temp. Rise @ 0.5 GPM 48, Temp. Rise @ 1.5 GPM 16
or, not quite handle a shower if one only needs to heat the water 16 degrees