I need to strap two single pole breakers together to make 2 pole.

It requires a 2 pole ganged breaker to meet code and guarantee the breaker is on two legs of the single split phase service. That in itself doesn't explain the 120 volts at the heater element.

Replace the two single breakers with the appropriate 2 pole ganged breaker. Before connecting the feed to the heater, turn on the ganged breaker and measure voltage across the breaker. If not 240VAC then there is a problem at the breaker panel.

If there's 240 at the breaker then you've somehow wired the thermostat incorrectly but can't imagine what you did.

In a traditional North American residential electrical panel (120/240 volt, single phase), installing a single width or single pole circuit breaker, you would expect to read 120 volts from the breaker terminal screw to either ground or neutral. A double width or double pole breaker would provide 120 volts from either of the breaker terminal screws to ground or neutral AND it will provide 240 volts BETWEEN the TWO breaker terminals.

A single-width circuit breaker case that contains two handles is NOT a two pole circuit breaker (these are called "tandem" or "1/2 size" breakers). This is because a single width breaker engages only one "line" in the panel. A double width breaker will engage 2 "lines" as a triple width breaker would engage 3 "lines" of a 3 phase panel. A single wide breaker can not physically engage more than 1 "line" so it will never be able to pass 240 volts.

You must install a double width / double pole breaker to safely supply a 240 volt circuit / device.

you dont
it requires an electrician with experience to connect it safely
call an accredited electrician and save your life

1. Remove battery from chain saw.

2. Separate main handle from chain saw

power head by pressing both release

buttons on main handle and pulling

apart. The release buttons are just in

front of the trigger.

3. Align rib on chain saw power head with

groove in power head adapter on pole.

4. Slide power head into power head

adapter until units "snap" together.

IMPORTANT: Both release

buttons on power head adapter must be

fully engaged.

5. Align rib on handle adapter on pole

with groove in main handle.

6. Slide main handle into handle adapter

until units "snap" together.

IMPORTANT: Both release buttons

on main handle must be fully

engaged.

7. Slide battery onto main handle until

release buttons "snap" together.

Be sure the battery is charged.

To extend the pole:

1. Loosen the clamping

lever. Pole will slide

freely.

2. Pull inner pole section out to desired

length of extension.

3. To lock pole in position, tighten clamping

lever.

The reason for using the quad, is so that if any one of them trips, they all trip. GE used to sell lever covers that would join the levers together. I don't know if they still do. And I don't know if the Bryant breaker is JUST 4 single poles with their levers connected together.

You need 240 breaker:
Notice that your 240V breaker is twice as wide as regular 120V breaker.
Notice that both switches are tied together on 240V breaker, making this a double-pole breaker.
For more information about breakers and 120-240V circuits:
http://waterheatertimer.org/See-inside-main-breaker-box.html
http://waterheatertimer.org/B220C.html

Try ebay.

T103M is 120Volt timer that can handle all the Christmas lights.
Minimum on-off time 1 hour.
Rotate dial until current time lines up with silver pointer.
Set on-off trippers on dial.
Let's go step by step.

1) T103 has terminals A 1 2 3 4 >> terminals are also called poles
DPST (double pole single throw) and SPST (single pole single throw) are two different ways to wire this particular timer.
T103 timer can be wired numerous ways... but your project is not complicated.
DPST means timer turns off two terminals/poles (double pole) with each click/throw of timer switch (single throw)
SPST means timer turns off one terminal/pole (single pole) with each click/throw of timer switch (single throw)

2) T103 timer is ST single throw, all the lights come on at same time. So this timer is 1 channel.
1 channel timers are either ON or OFF and everything turns on-off at same time.
You cannot stagger on-off times with 1 channel timer.
If you want upstairs and downstairs lights to come ON at different times, you need two timers .. or a 2-channel timer (which is different ballgame).

3) T103 timer has 120Volt clock motor that is connected to terminals A and 1.
Look at timer and you can see small white wires connected to A and 1 terminals that power 125V clock motor.
When wiring this timer, your wires from 20 amp breaker box connect to terminals A and 1.
Black hot wire from breaker must connect to terminal 1
White neutral wire from neutral busbar must connect to terminal A
http://waterheatertimer.org/How-to-wire-T104-Intermatic-timer.html#T103
http://waterheatertimer.org/B220C.html

4) Terminal 1 must be hot so when timer switch clicks ON, it sends power to terminal 2.
Your load wires connect to terminals A and 2
I made simple drawing of SPST option showing how to wire T103 to 3 receptacles.
Fixya downgrades image so it's hard to see.
Hot wire to terminal 1
Load wire to terminal 2
Neutrals on terminal A
To see image larger:
http://waterheatertimer.org/images/110-600-21Kb.jpg


If you want to wire timer for DPST, which is necessary for loads exceeding 2 horsepower (1500 Watts) on each terminal
Notice black jumper wire from terminal 1 to terminal 3
Notice all white neutral wires to terminal A
To see image larger:
http://waterheatertimer.org/images/110-600-17Kb.jpg

I made third image for guy who was wiring high amperage blowers, that show wiring for two T103 timers. Having two timers would let upstairs and downstairs lights come on at different times.
http://waterheatertimer.org/images/110-with-2-timers.jpg

I'm not up to date on PV systems so i will answer what i can about your question. The NEC applies to these installations so i hope you are familiar.

If the dc-ac inverter puts out 2 phase power then yes any two pole breaker rated for the amperage you are putting out would be fine. If the inverter puts out 120 then any single pole breaker will work.

That i know of, there are no 2 pole miniature or two handle breakers. There are breakers with two handles on them but they are tied to the same phase. the only thing i can think you may do would be to put a two handle single pole breaker in place of a regular breaker and then the one below it also. Then hook one leg off your inverter to one of the handles on the top breaker and the other leg to the bottom breaker.

Breakers do not have a line and load per say. The screw where wires are hoooked to is the load side of the automatic trip in the breaker however. The line would be where the breaker hooks to the bus bar but you can't really hook to that anyhow.

I would ensure what you do is up to code. There are safety issues involved. i assume you know your job though so i will leave it at that :) Hope this helped, write back if you feel i misunderstood.

You need to put in what we call a sub box. This should be done by a licensed electrician, but if you really want to do it yourself you will need a distribution box some wire and it has to be connected directly to your main lags from the meter box, this box will have a main breaker built into it and spaces for additional breakers, depending on your existing wiring the electrician might chose to wire the additional box directly to your meter base and not your existing box. Either way you really should seek local professional help on this project, just for your safety and to satisfy your home-owners insurance.

Have a great day..
Tim