In a current transformer (CT), burden is the electrical load connected to the secondary circuit, including meters, relays, wiring resistance, and any other connected devices. The CT is designed to deliver a faithful scaled current only within a certain burden range. If the burden is too high, the secondary voltage rises, the CT can saturate, and the measured current becomes inaccurate.
Burden matters in cyber security because many industrial monitoring and protection systems depend on CT readings to detect faults, overloads, or tampering. If burden is misconfigured, degraded by cable changes, or manipulated through added resistance or devices, the resulting blind spots can delay alarms or cause false readings. Defenders check burden during commissioning and maintenance, keep secondary wiring short and secure, and validate that meters and relays stay within the CT’s rated limits. In critical infrastructure, trustworthy measurements are part of the attack surface as much as the network itself.