To effectively design high voltage (HV) circuit breakers, the upwind meshfree (UM) scheme which was proposed by Choe et al.[5] and Park et al.[6] is tested. The UM scheme is implemented to a simplified model for the HV circuit breaker and showed a robust behavior even in a severe boundary condition. A good shock capturing is shown in the computations and a delicate gas diffusion through a slit is also computed, which is usually difficult to catch. Vector splitting method is employed to exploit the merit of meshfree methods in the hyperbolic problems.