This study presents an evaluation of the impact of distributed generation, of varying capacity and connected at different locations, on existing system fault-level estimation algorithms. A number of case studies have been simulated under different scenarios with DGs connected at different points on a 33/11 kV test network. Results show estimation errors when DGs are located downstream the fault-level measurement point and the errors are proportional to the assumed level of fault contribution from the DG. Errors were found to increase when the DGs were located electrically closer to the measurement/fault-level estimation point. Negligible errors were seen with the DG connected ‘upstream’ from the monitoring location. Possible solutions are discussed such as the use of distributed measurements to account for downstream DG fault levels. An approach to peak make fault-level estimation is also described utilising current IEC short-circuit calculation methods.