I just reviewed the HS pre-delivery booklet. Interesting. It shows a 50Amp breaker in the main panel, with four wires going to the GFI sub panel: #8 white, #10 green ground, and two # 8 wires for the load (blue and red).
That's correct, and it works just fine. You will have room in the sub-panel for another breaker to power an outlet, lighting or other devices - be sure to GFI-protect anything near the tub.
The GFI sub panel which is supplied by HS has a 20 amp and a 30 amp breaker. But from the GFI box - breakers it shows only 3 # 12 wires (
)(red, blue and white) from the 20 amp breaker to the spa,
that is fine - all you need.
and two #10 wires from the 30 amp breaker to the spa.
Yes: you don't need a neutral for the heater circuit. And yes, the GFI protection can and will work without a neutral.
Also looks like a #10 green going to te control box (at the spa ?).
Generally you should put the same size ground conductor all the way from your main panel to the spa. If you upsize the ground between the main panel and sub panel, then run the same to the tub.
Much smaller wires than I would have thought, though given the approx 45 feet of run to the spa would likely need to use larger wires - to make sure no voltage lost.
45 feet is a short run - wire size should be fine as quoted. You can always upsize, just be sure you can get the wire into the terminals. The sub panel can accomodate huge wire, the spa gets a bit tighter: but you still get the benefit of lower voltage loss even if you use larger wire and trim it to fit into the terminals at the end. Up to you.
Also, the chart advises the GFI sub panel to be not more than 100 feet from main panel (not a problem as mine would be within one foot),
The sub panel should
not be located within a five-foot 'reach radius' of the water. That's WATER, not tub. So you should either locate the sub panel farther away, or be sure to put a shelf, planter, step or somesuch over it so that there is no way to reach it while sitting in the tub.
So wiring lookd all very possible for either model. So, I wonder if there are there advangages to this two breaker system used by HS ?
I'm a fan of having the sub panel - I'm glad you are looking at two makers who encourage using them. They are big, meaty things that have the best method of Ground-Fault protection available.
The HS has the advantage of not sending the full 50 amp service into the tub, allowing for an extra circuit and it comes with the spa!! Also, you are splitting the tub's systems into two circuits, so if the heater has a problem the pumps can continue to run, one breaker fails, you can temp. switch to keep the tub going in a pinch. Aside from the obvious troubleshooting benefit this offer, these latter features may really be only important in freezing conditions I guess.
Both subpanels should allow for extra circuits, I know HS does.
Also, the Sub Panel and breakers that come with your HotSpring are covered by the spa warranty. Very nice. And most dealers sell them for reasonable prices if you ever move and want to start with a fresh one - though you could gut the breakers and buy a new box at a local supply house or home center. ($25). In fact, that's a plus: HS uses GE breakers which work well and generally cost less at home centers and such.
Yes, they are still pricey, but generally less than Square D or others.
The whole idea here is to protect you better, reduce the amp limit to the tub, and allow you to go out and buy a cheaper (non GFI) breaker for your main house panel. You already have that, but most folks have to start from scratch, and not all house panels offer GFI breakers anymore.
