Have not run anything through the spool of wire yet. Will keep it coiled for the time being and when I need to install it to the breaker box, then I will uncoil it and run a load through it at the same time as I will also need to check my IP67 connectors onced installed. So for the upcoming load test, I am using a 10ft cut portion of the 100ft (now 90ft spool) for my pigtail on my load bank with the same types of IP67 connectors. So it will be load bank (hard wired) via 10ft pigtail to a IP67 plug. That will plug into the IP67 receptacle that will be mounted and hard wired to the generator lugs.Are you load banking your set with the wire coiled on the spool? I remember reading somewhere about heat being an issue when you run power through a coil of wire. Might be worth looking into...
For connection to the house, the load bank gets disconnected and via another IP67 plug on the 90ft power cord to the panel, this plug gets plugged into the generator receptacle box which is hard wired to the generator lugs. The other end has a connector receptacle. This IP67 connector connects to the IP67 inlet mounted to an external box that is hard wired and further connected to the main panel at G, N, B2&4, and B4&6, on a dual pole 70AMP breaker providing 120VAC to each "leg" of the main power panel.
I do not think that the coil is an issue for this type of "low voltage" "low current" scheme of the electrical running(s) of the world.
Now if the coil was wrapped around an iron bar, that may be different. But when I was in the army, we ran generators with wire partially coiled to no detriment to either the generators or the equipment.