Electrical installation problem Differential switch

[Ali_TLM]

Hello

I have a room with an electrical installation in the configuration is as follows:

- A 300 mA differential connection circuit breaker
- A 30 mA Type AC differential switch
- 03 Divisional circuit breakers: PC (20A - 20A), lamp (16A)

1) I test with a lamp all my PCs (phase and neutral), the lamp lights up.

2) I test the lamp on the same PCs (phase and earth) the 30mA differential switch and the 300 mA differential connection circuit breaker trips at the same time.

3) I test the lamp on the same PC (neutral and earth) only the 30mA differential switch trips.

I do not understand where does the error of the 2nd and 3rd come from? Help me please !

Thank you

[boubka]

Hello
[/ quote] I test the lamp on the same PC (phase and earth)

normal

I test the lamp on the same PCs (neutral and earth) only the 30mA differential switch trips.

leakage current corresponding to the resistance of the earth electrode

so terrible land (above the norm)
voltage between earth and neutral greater than zero

[elephant]

You have a 230-400 network with earth neutral. It's usual.

When you test between neutral and earth, you therefore have no current flowing.

Attention:
it is not because the neutral is connected to the earth that it can be used as earth
it is forbidden to connect the neutral to earth downstream of the meter!