60 amp Sundance option

[galen]

I have 60 amp service and my Maxxus does not run the heater and all three pumps. If the heater is on and you turn the third pump on, the heater will turn off. The only time I see the tube cool down every much is when I'm running the air blower. That sucks in cool outside air, which inturn cools the water. But it takes a hour to see a drop of 4 degrees. I keep my tub at 102 in the winter. And after 45 minutes I'm ready to get the heck out.

[Brewman]

That sounds reasonable.  The Maxxus has 3 pumps where the other Sundance spas in question have only 2.  And for those spas, the 60 amp setting is necessary to run 2 pumps and the heater all at once.  Suppose there isn't enough headroom to get that third pump going and the heater on the same 60 amp setting.  And going up any more in power would certainly add a LOT to the cost of wiring the spa.  
 6 gauge copper would only be good for 60 amps, you'ld likely have to bump up to 4 or 2 gauge- and you do not want to work with that stuff unless you have to.  It's very stiff, and very expensive.  You'd also need fairly large conduit as well.  
 With all 3 pumps on at once, I can't imagine your heat would drop all that much anyway, unless it was very cold out.

[DaveMc]

I am a lay person but some of the answers here will get you in trouble---like--"the wireing is the same for a 50 or 60 amp---only the breaker needs to be upped"---wrong! wire size is importand if you don't want a toaster on the way to your tub.

[DaveMc]

"Wiring for 60 vs 50 amps. is the same, it's only the breaker that's different, assuming the sub panel is rated hight enough."
This not true---wire size from the main service to the sub panel is important---the wrong size will get you in trouble.