As shown in Fig. 6, some defective points have been detected in different areas of the PV field. Depending on their shape and location, these hot spots and hot areas can highlight different faults. Usually, if an entire module is warmer than usual, as partially shown in Fig. 1 (taken by a Fluke Ti 25 thermal camera), then some interconnection problems can be envisaged. On the other hand, if single cells or strings of cells are showing up as a hot spot or awarmer “patchwork pattern,” as shown in Fig. 7, the reason can usually be found either in defective bypass diodes, internal short-circuits, or in a cell mismatch, as well as due to snail trails phenomenon. Sometimes, shadowing and cracks in cells show up as hot spots (see Fig. 8) or polygonal patches in the thermal image. The temperature rise of a cell (or part of it) indicates a defective cell or shadowing.