I have the TI power board (inverter) and I connect it to the 48V power supply.
I do it like this:
I turn on the power supply (it doesn't have an on/off.. since I turn it on it delivers the supply), then I insert the positive (red) and finally the negative (gnd) which obviously closes the circuit.
It's already the second time that, as soon as the negative touches the power supply connector, I see a spark and hear a small bang when I connect the black wire (gnd) to the power supply. Luckily nothing broken.


Is this normal? ..I know it can happen, but better not
Should I connect both wires and THEN turn on the power supply?

I never noticed these things, perhaps because I worked with lower voltages

 

Those big capacitors charge instantly causing a large inrush of current.

Yeah, better to connect first, then turn on the supply.

 

Read section 3.3 of the datasheet.

 

so plugging anything live is rarely a good idea. always connect things BEFORE powering them up. you are just too slow for electricity. when you bring things close enough for current to flow, resistance is high... by the time you move another 0.001mm that contact surface is already burned. this is how what makes arc welding possible but in most cases it is highly undesirable. circuits need to be DESIGNED for hot plugging.