Because of increasing demand for reliable and renewable energy supplies, new high-voltage power lines are introduced into the environment. Some residents associate non-specific health complaints such as tiredness, headaches and neurological problems, with exposure to electromagnetic fields from nearby power lines (Cox et al., 2005). A recent study indicates that not actual proximity, but the perception of living near a power line is associated with reporting non-specific health complaints (Baliatsas et al., 2011). We study if these findings can be extended to a newly introduced power line which has not been put into operation yet. We hypothesize that the introduction of a new power line leads to more health complaints through perceptions of power line proximity, particularly in residents who expect to get health complaints from living near a power line. During the construction of a new power line route in the Netherlands residents living near (<500m, n = 710) and farther away (500-2000m, n = 515) completed an environmental health questionnaire. In agreement with earlier research no direct effects of actual proximity on the number and intensity of reported somatic and cognitive health complaints were found. As hypothesized, the relationship between actual proximity and non-specific health complaints was mediated by the perception of living near a power line. This effect was only present for residents who expected to get health complaints from living near a power line. These findings suggest that symptom reporting after the introduction of an environmental risk object is mediated by perceptions of proximity and moderated by perceived health risks of the object. The practical and conceptual implications of our results will be discussed.