An electrical system can include a diagnostic device that generates a first test signal at a first time. The electrical system can also include at least one energy transfer link coupled to the diagnostic device, where the first test signal flows through the at least one energy transfer link at the first time. The electrical system can further include a portable electrical load coupled to the at least one energy transfer link. The electrical system can also include a monitoring device coupled to the at least one energy transfer link, where the monitoring device is disposed between the diagnostic device and the portable electrical load. The first monitoring device can receive the first test signal, where the monitoring device executes, in response to the first test signal, a test procedure on the portable electrical load. The portable electrical load is portable relative to the diagnostic device.