The cable joint is the part with the highest fault rate in the cable system

the damage due to cable joint fault can be effectively reduced by the explosion-proof box. However

the existence of explosion-proof box will affect the temperature of the cable joint. In this paper

the 3D simplified model of 10 kV three core cable joint and explosion-proof box is set up. The Ansys simulation software is used to simulate the electromagnetic-heat and electromagnetic-heat-fluid two-way coupling of the 3D model to analysis the temperature field distribution at such three cases as no addition of explosion-proof box

addition of of explosion-proof box with sealant as the filler and addition of explosion-proof box without filler. Then

the influence on the peak temperature before and after the addition of the explosion-proof box due to such three factors as air convection heat transfer coefficient

ambient temperature and the thermal conductivity of sealant. The research results show that the temperature of cable joint is increased at two cases after addition of the explosion-proof box for the joint and

in case of no filler in the explosion-proof box

the temperature of the joint is more variable. With the increase of the heat transfer coefficient

the peak temperature difference of the joints before and after adding the explosion-proof box increases gradually. While

the influence of ambient temperature on the variation amplitude of peak temperature can be ignored before and after adding the explosion-proof box. The increase of thermal conductivity of sealant to a certain extent is conductive to the increase of the cable joint current carrying capacity.