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Inverter off. Can inverter capacitors still shock you?

kolek

Inventor of the Electron
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Sep 29, 2021
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Say you need to do some work on your inverter, in this case, connecting inverter to grid for the first time.
You switch off your PV inputs. Then you switch off the main DC breaker to disconnect your battery from the inverter. This should cause the inverter to bleed down the capacitors before shutting off due to lack of power.
Would it then be safe to work on the grid and load connectors on the inverter, or could there still be full capacitors on on the terminals that could shock you?
Maybe do a voltage check on the terminals before working on them?
 
Say you need to do some work on your inverter, in this case, connecting inverter to grid for the first time.
You switch off your PV inputs. Then you switch off the main DC breaker to disconnect your battery from the inverter. This should cause the inverter to bleed down the capacitors before shutting off due to lack of power.
Would it then be safe to work on the grid and load connectors on the inverter, or could there still be full capacitors on on the terminals that could shock you?
Maybe do a voltage check on the terminals before working on them?
I would say give it at least a good 15 minutes.
Of course doing a voltage check would be best.
 
Maybe do a voltage check on the terminals before working on them?

That would be a good idea.

Do as I say, not as I do.


I managed to get an AC shock after disconnecting battery cables.
 
On my XW yes, the caps will shock you with 48V.
I managed to get an AC shock after disconnecting battery cables.
Yeah I figured that's a possibility.
I'm using a 200W light bulb for my precharge circuit. What about using a light bulb to discharge the caps? With L1/L2/N I'm not sure though how to discharge though.
 
So connect light bulb to terminal to L1 & N, then connect it to L2 & N?
Oh I use the lightbulb to drain + and - on the battery terminals. I don't think my inverter would let anything out the AC side when it's off. But I've never tried.
 
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Capacitors can retain a charge even after power has been removed.
You should always drain the capacitors before working on systems that have them.

Many years ago my electrical engineering professor recalled a personal experience he had with capacitors. During WWII he was stationed on a Pacific island, I don’t recall where, where he was responsible for the island’s airfield radar systems. He said he had to do some maintenance on the radar system and did not discharge the capacitors because he “assumed” they were drained since the island power had been out for a few days because the island generator was down. He said he recalled opening the metal radar equipment container, removed the access plate, inserted his arm into the equipment rack….next thing he recalled was waking up finding himself on the other side of the equipment bin laying on the floor with burn marks on his arm and hand. He told us to NEVER assume the capacitors, especially BIG ones are empty/self discharged. Discharge them out first!
 
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