The PowerTags instructions sheet states that the PowerTags must be associated with an easily accessible upstream protection and circuit-breaker system, marked with callout A in the schematic below:
What type of protection (Block A) should be used?
The block A represents a protection (MCB, RCCB, switch) that allows the circuit monitored by PTag to be turned off. In most cases, it’s an existing device in the customer's installation. However, in some specific use cases where it’s very hard to turn off the circuit monitored by PTag (for example, in a data center), it can be useful to power the PTag with a dedicated protection. Any MCB up to the PTag's maximum current can be used, or a switch with an upstream MCB.