Siglent SDG1022X plus - Power voltage on GND - Page 1
Forum section: electronics / testgear

author: greg-2
author_rank: Contributor
timestamp: September 08, 2025, 06:12:29 pm
content: Hi folks,please help or advise me with my generator.I don't know this is normal situation or not. Is my generator is malfuncitoning or not.I found that depending on a way I put power plug to socket there is net voltage between Neutral power wire and GNDs of generator in case of socket without PE pin.Value of this voltage also depends on power button status (if gen is on or off).By GNDs I mean here gnd any of signal terminal or generator's ground terminal.Case 1. Left pin of plug (seen from back of plug) is connected to Neutral of socket. Right pin is conncected to Live. PE not connected.Power button OFF : Voltage between Neutral and generator GNDs is about 5 V ACPower button ON : this Voltage jumps to 117V AC (50Hz)Case 2. Left pin is connected to Live, Right is to Neutral, PE not connectedPower button OFF : Voltage between Neutral and generator GNDs is 230 V AC, 50 HzPower button ON : Voltage drops to 117 V ACIs this normal behaviour of this generators?I worked with this gen some while, touched its terminals with bare hand and felt no shock or any sensation so far.Greg

author: 2N3055
author_rank: Super Contributor
timestamp: September 08, 2025, 06:34:23 pm
content: Immediatelly unplug it and call somebody to check your installation.

author: greg-2
author_rank: Contributor
timestamp: September 08, 2025, 06:36:43 pm
content: Installation is OK!

author: voltsandjolts
author_rank: Unknown
timestamp: September 08, 2025, 06:48:26 pm
content: As per the manual, you must earth this unit:Quote

author: 2N3055
author_rank: Super Contributor
timestamp: September 08, 2025, 07:11:36 pm
content: Quote from: greg-2 on September 08, 2025, 06:36:43 pmNO it is NOT!!Otherwise you won't have voltage on the grounded chassis.If you insist (are sure) your socket is properly grounded, then try different power cable.You cannot operate metal case devices without protective earth connected.

author: greg-2
author_rank: Contributor
timestamp: September 08, 2025, 07:36:26 pm
content: My installation is an old type installation - sockets are without this PE pins, they have only neutral and live connections. BTW net voltage is 230V.Yes I know it is not the safest one but it is hard to impossible to change this.I tested with other socket and the results are identical.I will also test other equipment and maybe make some sub installation with PE sockets for tests.Greg

author: 2N3055
author_rank: Super Contributor
timestamp: September 08, 2025, 08:11:43 pm
content: OK thank you for confirming...All modern equipment with PE cable require PE to function normally.My advice to you would be to try and create at least part of your power where you do electronics to have proper PE sockets.Qualified electricians know how to do it safely.Stay safe.

author: tautech
author_rank: Super Contributor
timestamp: September 08, 2025, 08:44:22 pm
content: With these units you can add a ground connection if a suitable ground connection is available or you make your own....but if your other equipment is also ungrounded they could be all at a different PE potential.Ultimately the safest solution is have your mains installation checked for safety.

author: Martin72
author_rank: Super Contributor
timestamp: September 08, 2025, 09:07:30 pm
content: Quote from: greg-2 on September 08, 2025, 06:12:29 pmNot from the generator; this is the behavior of a protection class 2 connection (Euro plug without PE).The device will contain capacitors that are connected from live to PE, among other things for EMC reasons (filter).If these capacitors are small in value, they have high resistance at mains frequency—that is the only reason why you did not feel any effect when you touched the metal housing.However, this also means that protective measures/filters against PE may not be effective in your case because your installation apparently does not have PE.QuoteNot the safest...There's almost no safety at all.Of course it is possible to change it, but your home installation should be urgently renovated to this effect.If your home installation does not have grounding that extends to the outlets, then you also do not have a residual current device—something that can save lives.I would not be concerned about the generator, but rather about safety in general, and I would turn it off for the time being.

author: greg-2
author_rank: Contributor
timestamp: September 09, 2025, 03:46:24 pm
content: Thank you for explaining reason for what I believed was failure of equipment and thanks for pointing safety concerns. Thank you Martin.I wasn't aware all of this, and wasn't aware of being such ignorant. And I am stuck.