Safety requirement-Residual Current Device

[maypot]

Hi,

What are the most common safety requirements regarding the installation of ELCB in domestic installations ?
Is 30 mA leakage current considered a standard level for basic installations @ 110 v and 220 V ~ ?
What are the requirements for grounding in domestic installations ? Is it mandatory ? Or the installation of the ELCB is regarded as a safeguard against high impedance earthing ?
I am looking for views ( standard and legal ) from experts in the forum .

Thks for your input.

Bob

 

[ScottyUK]

What country?



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If we learn from our mistakes,
I'm getting a great education!

 

[Paulusgnome]

As I understand, it varies from country to country.
In New Zealand, we have compulsory RCD installation in all domestic installations. Electric ranges are permitted to be wired without, and pretty much everything else has to be wired via RCD.
The trip current is 30mA, the RCD must not trip at 0.5In, must trip within 300mS at In and must trip within 40mS at 5In, all of this is in line with international standards I think. In NZ the RCDs must also be sensitive to pulsed DC, which is not so common in other countries.
As you will appreciate, our electricians had some fun getting to grips with this. There are quite a few things that generate leakage currents to earth in normal operation (switchmode power supplies are especially bad for this), and too many of these on the same circuit has the RCD nuisance tripping. The starting transients generated by refrigerator compressor motors also causes a few headaches from time to time.

 

[maypot]

I am looking forward to have views of people using TT and TN- network ( US & UK ). Are RCD mandatory for a TN grounding network ?