After a full fault some parts of an NER enclosure may be hazardously hot. The effects of this can be mitigated by labelling, by ventilation design, by enclosure construction or by the addition of heat shields that keep the hot parts out of reach. Bearing in mind that substations are not heavily populated and that faults are rare and never full duration, a solution that does not add disproportionate cost is obviously wanted: we consider that large, clear warning labels (Danger: hot surfaces) are the best approach.