Harold:
1990 NEC was 75'; 93 changed to 25', and to date there is no requirement in the NEC for where the 120 volt originates from.
Using the "Rehab Card" gets them a 75' distance IF the original unit was pre 1993 install, after that 25'.
Getting deeper into this, a existing building being renovated, with no change in volume, installing RTUs today is under the 2005 NEC
Source is still the 'wild card'!
