A few things need consideration here.
1. is water coming from high level ground water? If so you probably have more water problems than just this underground raceway.
2. drainage around the building or structure. If water does not drain away from building very well it could follow raceway into structure either inside or outside of raceway.
3. is water entering at the outdoor end of the raceway? This could be for multiple reasons. Open ended raceway, no weatherhead, or cap on the weatherhead. Improperly oriented weatherhead. No drip loop in conductors that exit weatherhead. there could be other reasons
4. make sure you not only have drip loop in exposed conductors where they connect to service drop or other similar situations, but that the connectors used are arranged so they do not let water inside the conductor insulation, it will find a way through the conductor and into the structure eventually. Keeping the connections below the weatherhead effectively makes a plumbers "P" trap in the conductor and if the inlet is lower than the highest point of the trap the water will not flow past the trap. Pointing conductor ends downward so they will not let water inside conductor insulation is a good idea even if the connector is below the weatherhead.
5. condensation. This is pretty unavoidable, but if duct seal is used to prevent air migration through the raceway it should be much less of a problem than if there is no seal.