220 Two Breakers

You should be asking an electrician. Crazy to save money by asking this on a web forum that isn't even specialist electrical. You risk breaking code, invalidating insurance, causing major damage, refusal of supply by utility company, fire, injury or death.

Durf, Cen prolly right though some of the guys on a2k, like Man and Eng, might actually be able to help. Cen tends to be a bit overly critical at times

I've addressed others with similar probs, 7, no offense now, to invest in a cheap battery voltohmmeter, and get a friend to show ya how to use it. Ain't hard

But, eg, 'one ground and two hot leads' Durf, and again no offense, but doesn't make a lotta sense

Hi, Thanks for getting back to me with this,What I,m doing is hooking up a tankless ele. heater that draws 66AMPS. says use 70AMP breaker and 6gauge wire, Ok I got breaker, I look at the 2 foot lead that comes with heater and it looks like 8gauge? And get this on the wire it says 6AWG and then 8AWG on same wire??????? Never seen that before?
I dont have alot money to buy 30 feet of wire and spend whole day trying to fish it to panel, SO, we switch to a propane gas range so theres a 4 wire 8gauge running right pass room where heater is. [WAs a 3oamp tank there before] I hooked it up to 8gauge and wires got little warm and hummed?? So I doubled up the white and red and the black and green [10gauge coated ground] each on a 110volt leg and it works fine now, and I grounded it with the 10gauge ground from the other old hot water circuit which is what grounds 6gauge anyways.
Most of you will think I, nuts but its really over kill now with bigger wires.

Nah /durf, but let's hope we hear from an exp like Eng or Man

Doubtless Man7 you've solved your prob. However be sure there's no kinda mixup 'tween ret and gnd