I too have a Generac 5500 Generator. It is safely positioned on the side of my home, a double - wide on block foundation , on a concrete pad. I have a super clean (even vacuumed) crawl space.
I want to install a Reliance csr302 manual transfer switch to run JUST my well pump in a power outage. The pump is a Pentek 1/2hp, single phase, 230VAC, 2wire with earth ground, running off my house panel with a 20 amp breaker since installation in 2017.
I have viewed and calculated the voltage drop using the Southwire site (handy) I've seen posted here & if I were to use a 12ga. 4 wire run of about 20 feet to go under my house into the crawl space and back up to the breaker panel to make the connections I need to make there, I calculated a 3 volt drop.
My generator puts out a metered 236vac no load.
I ask this because most sites say install of the transfer switch should be 1.5' max from the panel. I have no room to do that, no basement, no attic , and the house main panel is an entry foyer on a shallow wall. I'm assuming that is NEC code the distance from the panel. My code books are all older, (1980's) so I don't know if that has changed since.
Currently I have run the pump in power out emergencies by wire nutting a feed from the generator on a 10 ga. extension cord with pigtails (Generac Supplied Cordset with the 120v multi-outlet head removed) to the pump pair I removed from my panel breaker. The isolation is there as I shut down my main at the panel AND outside below the meter, so there's no chance of feedback, but I want to install the transfer switch for safety & ease of switching over if I'm not home when the power fails.
So, can safely make that 20 foot "pick-up" wire run as I described above. I hope there's enough info here. Thanks Dan