Could be dangerous! If there is a direct short or a shorted rectifier diode in the power supply as is mentioned by at least one person on this forum, this could blow a circuit breaker due to the AC line getting to the 5000uF of capacitance inside the land power supply unit. If you have a trip on a ground fault interrupter then there is most likely leakage from the AC hot to the grounding pin. In any event, be very careful. There have been electrocutions with faulty ground fault interrupter hookups around pools.