I would suggest you reinstall the surge protection device in the service panel connecting the white wire to the grounded (neutral) in the service panel. This is the best place for a surge protection device as this is the origin of the surge. Should lightning strike the power lines the surge protector will slow things down before it gets to the interior of the house.
If you decide to leave it in that panel get a two pole breaker and land the protector on the breaker with the white where it is now.
Question one
It is obvious the ground bar is isolated from the electrical panel. Should this box be bonded to the grounding bar, OR should a separate ground rod be installed for grounding just the box OR should it be left as is? What does the code state regarding this issue?
Yes the disconnect needs to be bonded.
250.4(A) (3) Bonding of Electrical Equipment. Normally non–current-carrying conductive materials enclosing electrical conductors or equipment, or forming part of such equipment, shall be connected together and to the electrical supply source in a manner that establishes an effective ground-fault current path.
This can be done by simply bonding the bar to the disconnect with a bonding jumper sized by 250.122
Question two
someone stated this box should probably utilize a 90 amp breaker. As information, the outside box is fed from the main electrical panel located inside the home and there is a 100 amp breaker inside this panel. The outside panel utilizes two double pole breakers: a 30 amp breaker for the heat pump compressor and electrical AND a 60 amp breaker is used for ONLY the heat strips. I do believe this is correct.
Under the 2008 code the #2 aluminum feeder to the disconnect is only good for 75 amps.
338.10(B) (4) Installation Methods for Branch Circuits and Feeders.
(a) Interior Installations. In addition to the provisions of this article, Type SE service-entrance cable used for interior wiring shall comply with the installation requirements of Part II of Article 334.
To size the feeder to the disconnect we go to 215.2 which will refer you to several other sections concerning the heat and the hermetic refrigerant motor compressors.
If you follow these instructions you might find that the calculations are more than what is already there.
An easy way to do this is to look at each unit to see if it has the FLA (full load amps) marked on it. This may be in the form of MCA (minimum circuit ampacity).
The MCA will already have the 125% added to the load and nothing else will be required. If it is FLA then multiply that by 125% and add the two together for the ampacity for the feeder.
MY advice is simple……if you don’t mess with it you won’t have to change anything. I would bond the enclosure and remove the surge protector and do nothing more. I wouldn’t worry about installing the connector in the back of the box.
If you are going to install a connector to the back of the box then I would just replace the feeder with a four wire cable. Now you can use the panel for 120 volt circuits also.