In order to study the short-circuit resistant ability and fire protection measures of temporary earthing devices, the theoretical calculation and experiment of the copper and copper-clad aluminum(CCA) earthing cable in a short time fusing process has been conducted. It shows that the theoretical results of the fusing current of earthing cables in the adiabatic process are conservative, and the cross section has a certain safety margin through the calculation formula. Copper cable is prone to be fused than CCA cable under theoretical equivalent section. The addition of flame-retardant sheath can increase the fusing time of copper cable and has no obvious influence on the CCA cable. However, after the sheath is applied, the number of CCA splash beads is significantly reduced, which has a good protective effect against short-circuit fires.