23. Why will my GFCI breaker not set when first powered up?

The most likely cause is it is wired incorrectly with the load neutral and pigtail neutral wired together inside the external GFCI. Please consult with a licensed electrician to perform the GFCI wiring inspection. GFCI Load Center Wiring 1. Groundings. All groundings should come straight from the house panel to the grounding bar provided. It should be separated from the Neutral. There should be a grounding bar to connect all ground wires. 2. Neutral. The Neutral line coming from the main panel should be dedicated and not connected to ground. Neutral from the main panel should be connected to the Neutral Bus Bar along with only the Pig-tailed Neutral (curly white wire) from the GFCI breaker. The Load Neutral that goes to the spa pack should be connected on the Load Terminal off the GFCI breaker. Usually, this terminal will have a white dot on it. If the Load Neutral to the spa is connected on the Neutral Bus Bar, the GFCI breaker will always trip. 3. Line1. Line1 coming from the main panel should be dedicated and connects on Line1 terminal provided before the GFCI. Off the GFCI breaker terminal, Line1 load line should be connected to the spa pack. 4. Line2. Line2 coming from the main panel should be dedicated and connects on Line2 terminal provided before the GFCI. Off the GFCI breaker terminal, Line2 load line should be connected to the spa pack. IMPORTANT: On the Neutral Bus bar, there should only be TWO wires connected: The Curly Pigtail Neutral from the GFCI breaker, and the Neutral wire from the Main house panel. The Load Neutral wire (to Spa) needs to be connected directly off the GFCI breaker terminal. There should be a Load Neutral terminal off the GFCI breaker. If there isn't a Load Neutal terminal off the GFCI breaker, then you don't have a Spa rated GFCI. Make sure your GFCI is Spa rated. An illustration of a proper GFCI wiring is shown on page 5 of the Installation Manual provided with the spa pack/contoller purchase. NOTE: Do not consider a reading between Line 1 and Neutral as a short. The reading should be between 10 to 12 ohms, which is the resistance reading of the transformer. This is not a short.