Some 200 amp breaker panels are made with only 20 slots.
No. You can not buy a 200 amp that only occupies 2 slots on the panel.
If you mean can you put a single 20 amp breaker in an electric panel, the answer is yes. An electric panel is typically made to handle more breakers with values that add up to more than the rating of the panel on the supposition that you will never draw full load on all breakers. If you do the main breaker would trip. In your case you are under utilizing the panel, but this is not a problem.
It depends on the specific model and dimensions of the panel and circuit breaker. It's best to consult the product specifications or contact a professional electrician to ensure compatibility.
The dryer is 220VAC. You need a double pole breaker to get 220 out of a home breaker panel. Perhaps you should contact an electrician who understands wiring so that you don't burn your house down.
It is not recommended to replace a Westinghouse breaker with a GE breaker unless they are specifically listed as compatible for the same panel. Each breaker is designed for a specific panel and mixing brands can create safety hazards. It is best to consult an electrician to ensure compatibility and safety.
Only a Square D designed breaker can be installed in a Square D manufactured panel.
No, Siemens and Westinghouse breakers are not interchangeable as they are designed for different electrical panels and systems. It's important to always use the correct type and brand of breaker specified by the manufacturer of your electrical panel to ensure safety and compatibility.
Your question is a bit vague, but let's try a two part answer. If you have a GFCI breaker in an electric panel you should only have one connection at the breaker, but the breaker will protect all devices on the circuit. If you are talking about a GFCI outlet, they are equipped to extend the GFCI protection to other non-GFCI outlets by using the proper "output" connection on the GFCI.
The sub-panel need to be fed from the main panel, by way of a circuit breaker connected to one of the breaker locations. Or if your sub-panel has a main breaker installed you can feed from the main panel with a sub-feed lug kit. This looks like a breaker, but is only a point where you can branch off the sub panel.
No, if you have a Square D distribution panel only Square D breakers will fit in it.
If the breaker only trips once a week you may have a bad breaker or the breaker may not be large enough for your A/C unit. You should also have an electrician look for any loose connections from the unit to the breaker panel. (It is not uncommon to have a bad breaker)
It's often a small swing panel (a panel that is mounted to the side of another or to a wall that can be turned to face different directions). Typically it has a big dial and perhaps some light bulbs that indicate the voltages on either side of a breaker are in sync. The dial will spin slowly if there is any slip frequency between the two sides of the breaker. Usually there is one sync panel in a substation; all breaker sync connections run through this one sync panel, and only one can be turned on at a time.