Wiring array disconnect

I'm confused (not unusual). If you connect ground though a 3 conductor disconnect, and flip the switch, how is the array still grounded?

Assuming a negative ground system, the negative and ground would normally be made somewhere on the house side of the switch. If the switch breaks the negative, how is that held to ground potential? I have the array frame ground separate from the dc negative ground tie, but that's another can of worms.

Normally, as I understand it, the ground and negative would not be fused, switched, or otherwise have an easy way of disconnecting. Only the positive would have means of disconnection by way of breakers, fuses, or switches. In other words, yes, in a normally wired system, a 3 pole disconnect could be used to interrupt circuits from 3 arrays. The ground and negative should then both be at ground potential on the house side of the switch. Breaking the positive at the switch should put + wire on the house side at close to ground as well.