I have a friedrich mr18y3ea outside unit and mw18y3e inside unit what size wire for the two unit i think doublepole 20 amp outside unit 12 wire do you need a sept. wire for the inside unit or it come off the outside unit

Each unit comes with a specification label with the information of the minimum and maximum fuse or breaker to be used, Try to locate it at the outside unit. If it not readable use this guide. As a friend for a clamp electrical meter and use the amp to read the current the unit uses in only ones of the live wires that enter the outside unit. then if the current is less than 13 amps and the wire is AWG 14 use a 15 amps fuse or breaker, if is more than 13 but less than 16 and the wires are AWG 12 use a 20 amps fuse or breaker, if is more than 16 but less than 24 amps with wire AWG 10 use a 30 amps fuse or breaker.

Hope this can help.

Use 12 gauge wire with 20 amp breaker, otherwise the wire could overheat. The wire size and breaker size must match.
http://waterheatertimer.org/Color-codewire2.html

Your outlet will have amp rating on the device.
For example if device is rated for 15 amp, you can still use on 12 gauge wire if outlet is used for 1 TV or a lamp, but getting 20 amp outlet is best, especially in a shop or if a motor plugs into outlet.

You can connect as many wires as needed to the outlet.
Use the quick connects on back of device. Or the screws.
Black hot wire(s) go to side of outlet with narrow blade and brass screws.
White neutral wire(s) go to side of outlet with wide blade and silver screws.
Maximum 12 boxes per circuit breaker.
http://waterheatertimer.org/How-to-wire-switches.html
http://waterheatertimer.org/See-inside-main-breaker-box.html

Here are links that show basic wiring inside a breaker box.

Please look at the images.
If you need more help, answer back and we'll go to the next step

http://waterheatertimer.org/See-inside-main-breaker-box.html
http://waterheatertimer.org/240-v-water-heater-circuit.html
http://waterheatertimer.org/Circuit-breakers.html
http://waterheatertimer.org/Color-codewire2.html
http://waterheatertimer.org/Figure-Volts-Amps-Watts-for-water-heater.html

Breaker size:
15 amp breaker connects to 14 gauge wire
20 amp breaker connects to 12 gauge wire
30 amp breaker connects to 10 gauge wire
Home Depot and Lowes have a breaker and wire size size chart next to wire cutting machine
These stores have guys who know the basic breaker size for your big appliances
Each appliance has a name plate showing wattage and voltage.
The wattage tells you what size wire.
The voltage tells you what size breaker and whether you need a 120V breaker or 240V breaker.

To lay out your home wiring:
The kitchen microwave needs a 20Amp 120V 'dedicated' line that goes just to the microwave.
The rest of the kitchen plugs are served by another 20 amp 120V breaker
When laying out rest of house, figure how much wattage might be used in an area.
For example the den might have a big 500Watt TV, and 2 ceiling fans and 4 lights.
Add up the wattage and decide how many plugs and switches you want on each breaker.
Now let's say you have a 20Amp breaker which can carry 1920 Watts for the den.
Inside the breaker box you have a 12 gauge wire for the 20 Amp breaker.
The 12 gauge wire has a black, white and bare ground.
The black connects to breaker. The white and ground connect to Neutral busbar.
The 12 gauge wire leaves the breaker box and goes to the first box in the den.
This box is your junction box.
The junction box can be a switch box or a ceiling light box.
You cannot have any junction boxes that are covered by drywall.
Junction boxes must be accessible. All boxes must be accessible.
For example, you choose a ceiling box for your junction box.
The junction box is also the same box your ceiling light connect to.
From your junction box, you branch off a wire that goes to next box.
And then a wire branches off next box and goes to next box. And so on.

If you need more help, answer back and we can help.

two wires go from the inside unit to the outside unit. Y terminal and C terminal (both low voltage). Power should come from circuit breaker panel (20 or 30 amp double breaker).

The breaker is sized according to the size of the wire used in the circuit. The breakers task is to protect the wire from an over current.
The allowed sizes are
#14 wire .... 15 amp breaker
#12 wire ..... 20 amp breaker
#10 wire .. 30 amp breaker
To check if the oven and circuit are compatable .. run an extension for the oven to an outlet outside the kitchen and see if it holds.

Please Vote !!

The circuit is protected by the 15 amp breaker. That's what matters, the wire size and the breaker feeding it. It's OK to have a 20 amp recepticle fed by a 15 amp breaker.

There should be a full load amps or rated load amps on each of these units on the rating or nameplate. The ampacity or fuse size and wire size, which I think that's what you are wanting to know . The fuse size would be full or rated load amps times 125% and the wire size depending on the length of the run, 50 feet or less, (15 amps 14 gauge wire), (20 amps 12 gauge), (30 amps 10 gauge), and (40 amps 8 gauge).

I have the same tub and had a similar issue. We originally connected a 12guage with 20 amp circuit breaker and breaker kept trippin. The solution was to connect 10guage wire with a 30 amp breaker. Connect that to a gfi then connect the 12 guage wire coming out of the generator to the gfi (woulda made sense to just have 10g coming out but it was made in China). Being that theres only a short lead coming out of the generator its fine to run 10gauge, just make sure there connected seperately to a gfci breaker. The pump is fine 12 guage 20 amp.

yes, you did a good job. Sounds like you paralled them. Which is right buuuut what size are these heaters. Add the wattage of all of the heaters and divide by 120 and that is how much current you will be using. On a 20 amp breaker you can only pull 16 amps safely. I think you will be way over unless the heaters are 600 watts each. You are allowed 1800 watts on a 20 amp circuit.

Low voltage shorts can be a real pain to find!!! i would try a process of ellimination: first i would try to elliminate the thermostat. then id look for a wire that is vibrating on something in the cabinet.