Spa: Coleman 430
230v/40A (3-wire)

Just moved, now want to pass by you guys my final wiring configuration to hook up my spa. I am good at electronics and comfortable at basic home
electricty. I have read many forums and links therefore I feel comnfortable I have concluded on the correct compliant and safety measures to begin wiring.

200A service panel is full. I thought I could add a subpanel but I have read the only way to provide service voltage is from a 2-pole breaker in the main panel.
I originally thought I could someone how tap into the utility mains and configure the subpanel grounds & neutral accordingly using a bonding strap to
"act" like another primary service panel. However I have not seen anything to instruct how to do this and have settled on using tandem breakers and
consolidating 4 slots into 2 and freeing space to add a 2-pole 50A breaker.

This now eliminates the need for a subpanel for which to feed the external GFI/disconnect. I will now use 6/3G from the service panel to feed the 50A
external GFI/disconnect (installed outside greater than the min. 5ft required from spa). In the service panel: RED to one side of 2-pole breaker, BLK to other side,
both White and copper to Neutral bus. On GFI/Disconnect input side: RED to 1 pole, BLK to other pole, white to neutral bus, copper (GND) to
GND bus (separate bus).

From the external GFI/disconnect, 3 wires to spa (2 hots + 1 Gnd) 15ft.: RED to one side of 2-pole break, BLK to other side, GND from GND bus. Since the spa
does not use a white neutral and have read many forums on leaving the neutral connection on the load side of the GFI open (still keeping the pigtail
tied to neutral bus) I am confident this should work. Therefore the RED, BLK and GND will easily tie to the 3 corresponding lugs in the hottub panel.

Assuming the above is correct, my final query is the conduit used to run the 6/3G from the service panel thru the wall to the ext. GFI/Disconnect (total run 5ft.).
How is this done, what "parts" are suggested to connect the 2 boxes together?
Can this be plastic or metal conduit. I am assuming since the GND which is continous from the service panel (GND/Neutral bus) to GND bus on the
GFI/disconnect thru to the GND lug on the spa panel, there are no other grounding concerns for which have metal conduits from service panel to GFI/disconnect.

In addition,
However, reading other forums I am now concerned with my choice of breakers: 1 new 2-pole 50A and the 2 tandem 15A used to free up space.I too thought these were pretty standard as long as the rating and install "hook" were correct, I was good to go. But now I have read a bit more on this and see that it is recommended to use the original manufacturer replacement. Researching my service panel model, Gould GQ28MBB ITE Load Center (no hits in Google btw) using breakers types EQ-P (to be used in all slsots 1-28) and EQ-T (only to be used in slots 17-28), This led me to be more concerned than confident. Gould is no longer around, and have read it was bought out by ABB some time ago. So I found a site that sells ABB/ITE breakers hoping to have some types outlined that would help me finding a suitable replacement. It pointed to a Siemens model Q250, type EQ-P (2 pole 50A). Fair enough if I can go to my local hardware store and find exactly that. But there has to be a more generic approach to picking one off the shelf. The original breakers are by Gould and others that have been added are type QP. Am I making too much out of this, and if I see one that has the correct "hook" and bus bar clamp, could I assume with a reasonable amount of confidence thats appropriate?

Second revolves around tandem. My service panel is a CTL. I do not have tandem breakers there as originally thought so I have nothing to compare. But do to the nature of a CTB panel, does this mean the lower 17-28
slots used for tandem, limiting the amount of those I can use, after all the goal of CTL is to limit the number of circuits in a system. This will limit which slots I am allowed to consolidate. For instance I know I have unused curcuit in slot 2 but the breaker still exists with a load wire to an unused appliance. I cant pull off anything at this time to inspect the connections. But other forums mention "Slots" in the mounting rail, or forks in the busbar etc. Whats the best way to go about this now, selecting a tandem breaker. I am sure the secret lies in the allowable types described above (EQ-P and EQ-T) and how to find a suitable replacement.

Vince

No Neutral????

That's news to me. Sounds like a shock waiting to happen.

Without the neutral going to the tub from the sub panel, your GFI breaker is useless.

This is a very dangerous config.