I need a wireing diagram for two elament electric water heater. Mine runs on 220 volt, my question is what about the common or white wire where do i hook it to or do I not need it when running a 220 circut

Anon, It would only work if that was meant to be hooked up that way. Check the specifications in the manual or the plate on the heater itself. Check the attached links,instruction and guides, 1st link shows typical wire hook up on both 120 and 240 v. Good luck .
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Basic 220 Volt water heater circuit
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3 wire cord or 4 wire cord?
3 wire would be normally 120 volts
4 wires would be 240 volts
don't know if that would be common in an RV? If 120, is it 15 amp or 20 amp?
Again, would not know if 20 A would be found in an RV? If 20 A you would have one position in the cord - Sideways.

Any with the presumption 120 Volt - Same for either 15A or 20 A , Black wire onto Gold lug.
White wire onto Silver lug.
Green wire onto Green lug

if 220, comment back

I would start by checking the circuit breaker and the reset button if the heater has one just to get the easy possibilities out of the way. Next check the ground wire to may sure the ground wire is firmly connected. Electronics need a complete circuit in order to work. It is always possible that the wires have become corroded or broken. Please test the wiring to insure that all wires are unbroken. Please see the link below for more specific information.

http://waterheatertimer.org/Test-electricity-to-water-heater.html

Most Larger water heaters are 220 volt ac single phase. This means you need 3 wires, two hot wires one neutral or ground. You will need to come from the breaker box off of a dual breaker of 30 amps or better. See the manual with the new heater. In your breaker box you have two sides or in coming service. The right side and the left each side is hot 110volts ac. you need to pull one leg (hot) from each side into the dual breaker out to the heater connections. The ground or neutral wire is un-insulated copper. Run these wires out to the heater. One black hot at 110 vac, one white hot at 110 vac and one plain copper ground.

The hot water heater should come with an amperage rating on it.
They vary from 30 to 40 amps, and then 10 or 8 gauge wire.
(All hot water heaters are 220 volt.)
I believe the 602 uses a 4500 watt element.
Divide 4500 by 220, and you get about 20 amps.

If you want to be on the safe side, you go with the heavier wire, 8 gauge, and then go with the smaller breaker that is more easily tripped, 30 amps. That way you can switch to a 40 amp breaker in the future, without having to change the wiring. The goal is to always make sure the wire is rated higher than the breaker. You want you breaker to trip before your wire melts.
But technically a 30 amp breaker and 10 gauge wire would be fine for this heater.

And since it is 220 volt, you will always use a double breaker.
That is because 220 volt appliances don't use a ground, but instead use the potential between to power wires that are 180 degrees out of phase. AC always does a sine wave, and the 2 power leads coming into the house are always out of phase. When one is 110 volts up, the other is down. So the total between them is 220 volts. And the way they intentionally zigzag the breaker box, 2 breakers next to each other always are on opposite power lines.

If you have any doubts at all about 220 and water heater wiring, please ask again. Wiring is not hard, but you have to understand what you are doing, or else you can cause serious consequences.
For example, if you use wire nuts or wrap wire around a screw, you need to always turn them clockwise, so they pull the wire when tightened.
You also always need to ground the chassis with a green safety wire.
Since a 220 hot water heater uses 2 power wires and a safety ground, the white wire should be striped with a permanent marker, so that it is not confused with the white neutral wire of a 110 volt appliance.

Hello,You are correct! Black/blue=black & Yellow=white 220volt single phase power.There are 3 wires for 3 phase power connection NOT the case in a home.Also an "off peak"timer option would use (black) only controlling the bottom element and (blue) controlling the top element.

First do you have 220 volt power to the heater?
Second do you have 220 volt power to both elements?
Third do a ohm test on both elements with the wires disconnected
if it shows OL then your element is blown
Forth if you have power to only one element then your control is bad.
Good Luck

make sure you purchased nthe correct timer and not a 220 volt timer for water heater use , you could still turn on and off manually but you would need 220 volt to run timer may sound silly but i have seen it several times before , look on the door plate and be sure it is a 120 volt 1 phase tmr motor

According to the user manual below, it's a 50 amp heater, therefore, you need 6 AWG electrical cable and a 50 amp double pole (220 volt) breaker in the main service panel.

You need two hot wires and a ground wire. The cable would be specified as 6/2 w/ ground. The 2 hot wires in the cable would be red & black or black & black -- these attach to L1 & L2 respectively. ( L = Line )

More info, let me know.

Charlie

http://ecx.images-amazon.com/images/I/A1b%2BxE2vITS.pdf