You may think it is a strange phenomenon to see the wires heating-up inside the switchboard, but surely it should be known from those school days that the electric current heats up the circuits due to resistance in all conductors.
It is not a problem when the temperature rises above the ambient by about 20 deg.C. However, any further excursions from that point-on is a clear indication of both overload and overheating. This in turn increases your risk of electrical fire, if left undiscovered. Moreover, your energy bill contains that extra heat produced in circuits for which you are paying for with no benefit in return.