G
Guest123
Hey.
For a TT system the max Zs values in 7671 are not applicable, on the next page you will se for TT systems the the max is 1667ohms to enable operation of a 30mA RCD in the desired times at a safe touch voltage of 50V.
Really the RA should be well below 200ohms as this is the accepted value (about 100ohms is spot on) allowing for soil conditions weather etc. As you have 39ohms you have an excellent reading there so no need to worry at all.
For a TT system the max Zs values in 7671 are not applicable, on the next page you will se for TT systems the the max is 1667ohms to enable operation of a 30mA RCD in the desired times at a safe touch voltage of 50V.
Really the RA should be well below 200ohms as this is the accepted value (about 100ohms is spot on) allowing for soil conditions weather etc. As you have 39ohms you have an excellent reading there so no need to worry at all.