Symantec appliances come with redundant power supplies so that if one fails, the system continues to operate with the remaining power supply. The power supplies can be replaced while the system is up and running without interruption to operations. For this reason, we often suggest removal of a power supply to test if Call Home is working as expected.
We have noticed that deployed appliance have sometimes not restored the System back to redundant power operation after removing one power supply. Call Home or other notification Methods (SMTP or SNMP) will notify Symantec or the customer if the system has the power in a non redundant configuration. This should be prevented where unecessary
It is wise for proper protection that the system be returned to a redundant power configuration as soon as possible. Other, there is risk having a second failure bring down the system.