When an Evaporator goes into Defrost Mode, the most common operation for an Evaporator with _Electric Defrost_ will have the Fans turned OFF as the Defrost Heaters are ON.
Air Defrost, and sometimes Hot Gas Defrost Modes will keep the Fans ON while Defrost Mode is active.
In your case, it is safe to Ass-ume the Fans will be shut down during Defrost Mode.
The Design Maximum Load for the Evaporator in question will be 26.09A - the Defrost Heater load.
There _SHOULD BE_ Two (2) individual Circuits feeding the Evaporator, which are typically derived from the Condensing Unit:
a.: Fan Circuit
b.: Defrost Circuit.
Per standard installations, Two Safety Switches (Disconnects) are mounted to the Evaporator;
One for the Fan Motors,
One for the Defrost Heaters.
Fan Disconnect should be a Fusible type, with (3) RK5 20 Amp Fuses (240V or 600V, as applicable).
The Defrost Heaters do not require Fuses at the Unit, just a local Disconnecting means, so a Branch Circuit OCPD of 30 - 35 Amps is compliant.
1.: In Defrost Mode, each Evaporator should draw the rated 26.09A steadily for a minimum 15 Minutes to a maximum 60 Minutes.
2.: Use NEMA 3R Enclosures as minimum. We use NEMA 4X commonly.
Drop from the Lid with LFMC (Sealtite); Use "Sealed Penetrations".
3.: If the Target Temperature is at, or below 34°F (2°C), use Conductors with XHHW Insulation.
4.: For extremely cold Environments, consider using "FREP" Cable.
5.: Verify if the Scope of Work includes Control Wiring (drop an additional Sealtite for this), along with Terminations (Defrost).
6.: The Fans and Defrost Heaters may derive from a Panelboard, in lieu of the Condensing Unit.
In this case, One 30 Amp Branch Circuit may be used for the Fans and Defrost.
A lot of this depends on what Spec's have been placed on the Proposed Installation.
If you have additional questions, feel free to contact me directly.
Scott " 35 " Thompson
Just Say NO To Green Eggs And Ham!