Max voltage is 150VDC / 100VAC.
The voltage channels are not designed to carry much current, but should be safe up to at least 50mA or so.
The current channel is good for up to 500mA.
The relays have an insulation resistance of >1GΩ each, and the 150V spacing on the PCB should lead to very low PCB leakages. Overall system insulation resistance should be on the order of >100MΩ, but I don't have the equipment required to verify that precisely, and it will vary with installation.
So far it's made a great general purpose MUX. One installation has five of these cards plus a control-only version of the card in a stack to make a:
40:1 DMM MUX,
20:1 Signal Generator CH1 MUX,
20:1 Signal Generator CH2 MUX,
20:1 Scope CH1 MUX,
20:1 Scope CH2 MUX,
14:1 Power relay MUX Controller,
All of which are controlled by one SPI port.
Switching time is about 20ms, but that can only be accomplished with microcontroller control, python with a labjack tends to be a bit slower, about 50-100ms to switch.
Full schematics and more details are available
here! I also have a full KiCad footprint for the card, so designing it onto a motherboard is like dropping in one large component. The schematics get a little tricky to understand, but pretty simple as far as layout is concerned.