Even isolating the bike from ground, the bike itself is a return point. Even then, you have + and - on the board, so while you may not take a heart shot of DC it'll still burn a nice little hole in your finger if you come across it wrong. Not to mention a DC arc just grows and GROWS, it does not self extinguish 50/60 times a second like ac will. I used to have to work on 130 vdc live at times and that shit will just creep everywhere, especially if it's a humid day. It will also reach out and touch you if it can and It'll hold you too, it won't shake or throw you like AC can. Another thing that can be helpful is wrap your tools in electrical tape except for the very end that is being used, like a screwdriver, wrap it all the way to the very tip that goes into the screw head, that way if something does accidentally touch, it's insulated.
Aaron
Hi,
no it isn't. HV Systems are Isolated to every part of the bike. The only parts that have voltage on it are the HV Cables, Cells etc.
HV Voltage is NOT conducted back to the frame (except you have an isolation fault). There shouldn't be, and in normal operation there isn't any potential on the frame, battery housing etc. (only a few tenths of volts from capacitive loading). If you touch both potentials, yes you'll get lightend up pretty darn bright, but touching one potential and the Frame, Battery housing won't do any harm (But i wouldn't do it either or advise someone doing this, when working on active Batteries you have to wear at least 318kj arc proof gear), because there are at least 200.000 Ohms of isolation resistance between you and the potential (500 ohms/V; Energicas are above 300V) 
This is the issue. If you have an isolation fault, you could get electrocuted from touching just plus or minus, depending on which is touching the frame. Since something is wrong with my bike, there could be some isolation or grounding problem. I would never risk it.
Isolating the bike from the ground means that I will not get electrocuted from JUST touching plus or minus, if there is an isolation fault. - I would have to touch the frame too.
No reason for not isolating the bike.
If something on the PSU or other device is burnt or broken, there could very well be an isolation fault. The isolation fault could happen on the PCBs themselves.
The short circuit level is very very low where I am working, so I don't use arc protective gear. Only goggles and gloves.
I would wear arc protective clothing if I were to connect/disconnect the busbar for example, even though the operation from pictures seems, unless there is an isolation fault. If one touches the busbar coupler with a screwdriver, and the frame at the same time, when there is an isolation fault, you have fireworks.
Anyways. I found a new PSU online, and I am going to plug it in next week. Wish me luck
