I have a questions about AC and DC components being grounded to the same spot. I have a power supply box that takes in 120V AC and brings that into a transformer that converts it to 24V DC. On the way into the box the ground wire from the 120V AC is brought into a grounding terminal block and from there it goes to the metal base plate on the enclosure and into one of the inputs on the 120V AC to 24V DC transformer. Outside of the box I have a 24V DC pump motor. This motor has 3 wires coming out of it 2 for the 24V DC power and a green ground wire. These 3 wires are brought into this power supply box thru a cable gland. The 2 power wires connect to the output of the transformer. My question has to do with the ground wire for the pump. Can I connect this wire to the same terminal block as the 120V AC ground wires. The terminal blocks that the ground wires go into have a metal to metal contact with the base plate of the power supply so everything is grounded with the 120V AC ground wire. That being said if I cannot mix these ground wires then I do not know what to do with the 24V DC pump ground. Could I install a diode in line with the pump ground so current could flow from the pump into the ground in my enclosure but not from the enclosure into the pump? Is this even needed? Any help is appreciated. Thanks.