How do i replace 12/2 romex 110amp wires that overheated melted insulation in my 1990 rv?

SOURCE: Problems with a GFCI outlet (no voltage). GFCI

if your room is powered by one breaker you need only one gfci and it has to be hooked up correctly to protect the other outlets a new gfci will have a tape tag over the out side usually the top set of nuts the water in the panel is a major fire hazard i would fix this problem first your feed to the gfci may have shorted out in the wall between the breaker and the gfci if it is wired separate from the other gfci in that room one thing you can do to save calling an electrician is go to lows home depot or any electrical store and purchase a plug in tester they are inexpensive and easy to use it will tell you if wires are hooked up correctly backwards or if you have a short somewhere in the line this is the same little gadget that an electrical inspector uses to make sure new homes are wired correctly an outlet will still work even if some wires are incorrect in the circuit the outlet tester confirms all is good and safe

SOURCE: I have a m6w12w7a a/c and only have a 110 v

No, you cannot do that.

SOURCE: i hooked up a 20amp circuit breaker to a 15amp recp. then to a 20amp gfci but my outlet tester reads open nutral. what's wrong?

You've lost a neutral connection at: one of the terminals somewhere; inside the outlet; broken strap between the neutral pads on the standard outlet; or the tester is providing an erroneous indication.

Does it read OK on the BOTH receptacles of the first outlet? Check the terminals that provide output on the first outlet and the LINE terminals of the GFCI . Bad at the first outlet? Check the input on the first outlet. Bad? Check splices between outlet and service panel and neutral connection at neutral bus bar inside panel. OK? Check the input to the GFCI - make sure on LINE terminals and proper polarity is observed.

Double check the line and load terminal screws of the GFCI outlet. Make sure that the power coming into the GFCI is connected to the LINE terminals. Be sure to connect the HOT and NEUTRAL wires to the proper LINE terminals. Neutral conductor (white) connects to the silver colored screws and hot (black or red) connects to the gold colored LINE screws. If you are sending power out to supply additional loads that are to be GFCI protected, the rules above apply - but connect to the LOAD screws.

SOURCE: Dedicated 20 amp outlet

Ideally you should run the line straight from the circuit breaker out to your hot tub, but if the line running from your circuit breaker to the box you're using now is 20amp. you can absolutely connected to that. to be up to code it cannot be an open box it needs to be closed After you wire in your 70ft connection. (that's assuming the box that you're using is dedicated already to your hot tub) then the only difference would be is your using extra line and costing you tenths of a penny extra and electricity per hour.