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Isolation transformer - Voltage between output and ground
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S. Petrukhin:

--- Quote from: m k on February 11, 2024, 04:34:03 pm ---The whole area of the building was also ESD protected.

--- End quote ---

The whole building was filled with only iron, like a lathe shop? Did nothing dielectric exist?
m k:
D as discharge.
Protected against unwanted discharged.

Charges can't be avoided.
andy2000:
One example of where an isolation transformer is useful is when I need to work on the primary side of a SMPS.  It allows me to connect the ground lead of my scope probe to the hot primary side ground.  Such power supplies often have a large heat sink on the primary side that is tied to the hot ground.  Using an isolation transformer means I don't have to worry about accidentally touching this.  Both of these remain true even if the safety ground is connected.
S. Petrukhin:

--- Quote from: andy2000 on February 11, 2024, 05:02:35 pm ---One example of where an isolation transformer is useful is when I need to work on the primary side of a SMPS.  It allows me to connect the ground lead of my scope probe to the hot primary side ground.  Such power supplies often have a large heat sink on the primary side that is tied to the hot ground.  Using an isolation transformer means I don't have to worry about accidentally touching this.  Both of these remain true even if the safety ground is connected.

--- End quote ---

If you decide to participate in the life of the high-voltage side, then the separating transformer will protect you by galvanic isolation from the phase. A rubber mat under your feet will do the same. Or rubber gloves.  :)

But this is not the solution!
1. You can touch the two conductors in the high-voltage part.
2. If you detach from the PE circuit, you will receive interference in the air.
3. By connecting the ground terminal of the oscilloscope, you will receive a PE conductor from oscilloscope and the whole earth jumps with interference.

The most reasonable thing is probably to use a differential probe and be careful when performing manipulations only after power is turned off.
Do not rely on an insulating transformer.
Siwastaja:

--- Quote from: andy2000 on February 11, 2024, 05:02:35 pm ---One example of where an isolation transformer is useful is when I need to work on the primary side of a SMPS.  It allows me to connect the ground lead of my scope probe to the hot primary side ground.  Such power supplies often have a large heat sink on the primary side that is tied to the hot ground.  Using an isolation transformer means I don't have to worry about accidentally touching this. 

--- End quote ---

This must be a troll, must be a troll, must be a troll.... I truly HOPE this is a troll.

Note to those who don't understand why this is a troll: isolation transformer here gives you the false sense of security, while the oscilloscope ground lead re-establishes the galvanic connection to building earth, therefore making the primary side, which andy2000 does not worry about touching, lethally dangerous again.
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