72kVA
high voltage cable with loadbreak elbows
There's very little point in having a distribution transformer if its secondary winding isn't connected to a load! So, to answer your question, a 'secondary system' (by which you, presumably, mean 'load'), isn't 'essential' to a distribution transformer, it could just sit there doing nothing!
120/208VAC
false
an interlocking device
200 amp/25ft long cable
The amperage rating of the Mission Essential Power (MEP) circuit breaker for the secondary distribution center will vary depending on the specific design and requirements of the system. It is generally sized to handle the maximum expected electrical load of the critical equipment in the facility to ensure reliable power distribution in case of an outage. It is recommended to consult the electrical engineering plans or specifications for the exact amperage rating of the MEP circuit breaker in the secondary distribution center.
Primary electrical distribution carries medium voltage power to distribution transformers near the customers. Secondary electrical distribution transfers the power from the transformer to the households.
It is connected to the secondary side.
the three phase indicator lights will illuminate
This isn't always the case, although it is common throughout Europe. It is because high-voltage transmission and distribution lines are three-wire systems, while low-voltage distribution systems are four-wire systems.
The primary winding is the winding connected to the supply, while the secondary winding is the winding connected to the load. The terms, 'primary' and 'secondary' are unrelated to voltage levels.