:confused: 4 wire 100amp service box but only 3 wires?
I replaced my water heater with a tankless water heater. My service box is set up for hot, hot, neutral, and appliance ground for 220 watt hook up. But the water heater only has 3 wires, hot hot, and "Bare wire" ground. I currently have the water heater connected as, hot, hot, to breaker, and the bare ground wire to appliance ground. Is this correct? As I have been experiencing ground fault type shocks through out the house ever since I installed the water heater. How can I correct this and eliminate the shocks from touching other appliances in the house. Breaker box is in the house,(Trailer), has separate ground wire to the ground, then Hot, Hot, and Neutral to outside pole w/ 100 amp service disconnect box w/ 100amp fuses.

:confused:
You have a two-phase 220 Volt supply (hot-hot), a neutral for 110 Volt supply with any of the hot wires, and a ground.
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General :
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Any 220 Volt appliance requires 2 hot's and a ground. A neutral wire is in this specific circuit not needed. The "bare" wire is a ground wire.
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Any 110 Volt appliance requires one hot, one neutral, and one ground wire.
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Water heater
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If the water heater is a 220 Volt type, the neutral wire remains unconnected.
The shocks you experience indicate that you most probably have connected the ground to the neutral wire, or one of them to some hot point, or (instead of the ground wire) the neutral to the heater ground. Just check your wiring.
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Alternatively there also may be an isolation leak in the heater to ground.
To check disconnect the hot wires of the heater and check if the shock problem is still there. If so, the problem is elsewhere. If the problem is gone, use a multimeter to check the isolation between the earth points and either hot wire. Note that there is only an electric connection between heating element and wiring if there is water pressure and the tap is open. A pressure sensor inside the heater only makes an electric connection under these conditions. So either open up the heater unit to measure between the actual heater wires and ground, or apply tap water and open the warm water tap and measure between the normal connections.
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Ground
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The data you provided allows for even one more possible ADDITIONAL cause for your shock problem : your ground wire may be connected to a very poor ground point. A good ground will prevent you from feeling any shocks on appliances. Have your ground point checked by a professional. It may be so poor, that leak currents are not grounded properly.
A good ground could save your life.
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Success!
As always : if you require more info, please let me know. If this solves your problem, please rate the answer provided! Feed back is always appreciated!
;)

Breaker box is in the house,(Trailer), has separate ground wire to the ground, then Hot, Hot, and Neutral to outside pole w/ 100 amp service disconnect box w/ 100amp fuses.Exaplain this a little better.
Do you actually have only three wires going out to the pole from the trailer? What is this ground you are talking about? Where does it go and where is it connected on both ends?

What about the ground from the water heater? Where is that connected in the panel? There should be two separate bars for grounds and neutrals in your panel.

A mobile homes requires FOUR wires back to the service equipment. A grounding conductor is mandatory, this is where you get your safety ground that prevents the problems you are describing.
I suspect this ground is no correct and giving your these issues.