Issue
8kva Symmetra LX systems have a sticker on the rear of the UPS that specifies 100A input.
Product Line
Symmetra LX
Environment
Symmetra LX systems scalable to a maximum of 8kva
Cause
It is normal for an 8kva Symmetra LX frame to have a sticker on the rear that specifies a 100 amp input.  This sticker refers to internal specifications and has nothing to do with the manufacturer's input/output wiring recommendations.  The reason for this is that both the 8kva and 16kva Symmetra LX systems ship with the same frame electronics module.  This means that each system's internal wiring is rated for 100 amps despite the fact that the 8kva LX must be put on a 50A circuit for proper over-current protection.
Resolution
The 8kva LX system requires the customer to install a 50 amp circuit breaker to feed the UPS.  Refer to the Electrical Installation manual under the Documentation tab of the product page on apc.com.