Q$28.$ Having completed the three electrode test on an earth electrode and calculated the percentage deviation, what percentage is considered to be very good?

a$.1\%$

b$.2\%$

c$.59\%$

d$.20\%$

Q$29.$ The maximum earth electrode resistance, in a TT system, where the circuit is protected by a $30$ mA RCD to comply with the maximum permitted level of touch voltage is:

a$.1666\mathrm{.}7\mathrm{.}0$

b$.17666\mathrm{.}70$

$\backslash$tau $.166\mathrm{.}60$

d$.5\mathrm{.}00$

Q$30.$ Guidance Note $3$ advises that periodic testing be carried out:

a$.$ At night

b$.$ Avoiding unnecessary dismantling

c$.$ With all circuits isolated

d$.$ By a minimum of $2$ people

Q$31.$ Where it is impossible or impractical to disconnect the load from a circuit under test during a periodic inspection what alternative should be used to the standard method of insulation resistance test?

a$.$ Miss this test out

b$.$ Test with the load connected

c$.$ Test between neutral and earth only

d$.$ Test between L & N together and earth