\de-lurk
This one strikes me as quite interesting. The spa (tub) calls for a 60amp breaker. The setup is all SquareD QO stuff. SquareD has a perfectly nice 2=pole GFCI 60amp breaker. The breaker is the disconnect, it's in a nice external panel, greater than 5 feet, in line of sight. (sounds good right?)
NOPE. It seems in the line of SquareD QO GFCI 2-pole breakers (20, 30, 50, 60) the 60 is odd. Its not like the others. All the breakers (except the 60) can handle single and two pole loads. Seems in complicated devices such as a spa pack sometimes one leg is used to make '120v'. The 60 can't do this; its pure 240v (2-pole). SO, it was never the heater. It seemed to be as every pump could be run (in the purge/test/startup time). But after a uniform period, the breaker would trip. Most certainly seemed like the heater. Nope, no clue what it is but resolved the issue. Installed a SquareD QO 2-pole 50amp (too close but seems to work to the stated 48a max draw). Tub runs fine. All is fine.
(also no service gate valves...)
So, warning to those out there who like SquareD. QO 60a.... not good for this (no clue what it might actually be good for if not a spa)
WL
/re-lurk
footnote:
From the Square D FAQ website:
Where do you connect the load neutral wire on a QO260GFI?
Answer: The QO260GFI does not have a load neutral connection and is to be used on 240vac 2 wire applications only. Not to be used on 120/240 vac applications where two hot wires and a neutral is required. If a 60 amp GFI breaker is needed on a 120/240 vac system, divide the 120/240 vac loads and put the 240 vac loads on the QO260GFI and put the 120 vac loads on a single pole GFI breaker like the QO115GFI