ProMbrooke:

gkenyon:

There is no limit to touch voltage in IEC 60364-4-41 for TN systems (as today)


For TT systems, same disconnection times, but touch voltage limited to 50 V by equipotential bonding. This is not the same as today.


The disconnection times in Table 41 A (TN systems) are AC only but otherwise as they are for TN systems today, way back to 1992 at least, perhaps before ... As below for the 1999 Ed for example:


U0        Disconnection time (s)

120           0.8

230           0.4

277           0.4

400           0.2

>400         0.1

So where are they getting wet locations from?

I don't understand.


Compare then with now (Section 701, or IEC 60364-7-701).

Then (pre BS 7671:2008): Disconnection times as per Table 41A, PLUS supplementary local equipotential bonding [to achieve local touch voltage up to 50 V]

Now (BS 7671:2008 onwards): Disconnection times as per Table 41.1, PLUS additional protection of all circuits serving, and passing through zones 1 and 2 of the location but not serving the location, by 30 mA RCD either:

• supplementary local protective bonding [to achieve local touch voltage up to 50 V];
  
  OR

• main protective bonding PLUS confirmation that all extraneous-conductive-parts of the location are connected to the main protective bonding PLUS additional protection of all final circuits serving the location by 30 mA RCD (but this last provision doubles up on 701.411.3.3 a little; however, consider additions and alterations to existing installation).

ProMbrooke:

gkenyon:

There is no limit to touch voltage in IEC 60364-4-41 for TN systems (as today)


For TT systems, same disconnection times, but touch voltage limited to 50 V by equipotential bonding. This is not the same as today.


The disconnection times in Table 41 A (TN systems) are AC only but otherwise as they are for TN systems today, way back to 1992 at least, perhaps before ... As below for the 1999 Ed for example:


U0        Disconnection time (s)

120           0.8

230           0.4

277           0.4

400           0.2

>400         0.1

So where are they getting wet locations from?

I don't understand.


Compare then with now (Section 701, or IEC 60364-7-701).

Then (pre BS 7671:2008): Disconnection times as per Table 41A, PLUS supplementary local equipotential bonding [to achieve local touch voltage up to 50 V]

Now (BS 7671:2008 onwards): Disconnection times as per Table 41.1, PLUS additional protection of all circuits serving, and passing through zones 1 and 2 of the location but not serving the location, by 30 mA RCD either:

• supplementary local protective bonding [to achieve local touch voltage up to 50 V];
  
  OR

• main protective bonding PLUS confirmation that all extraneous-conductive-parts of the location are connected to the main protective bonding PLUS additional protection of all final circuits serving the location by 30 mA RCD (but this last provision doubles up on 701.411.3.3 a little; however, consider additions and alterations to existing installation).