Question 1

The maximum tabulated Zs for a protective device as shown in BS 7671 is 1.44â„¦, the maximum permissible measured Zs will be

Accepted Answer

A)   1.44â„¦
B)   1.43â„¦
C)   1.15â„¦
D)   1.08â„¦E) A) and D)
F) A) and C) C

Question 2

The stated maximum Ze for a TN-S supply system is

Accepted Answer

A)   0.35Ω
B)   0.21Ω
C)   0.8Ω
D)   0.85ΩE) B) and C)
F) A) and C) C

Question 3

Where BS 7671 show a protective device as having a maximum Zs value of 2.3O the maximum corrected value will be

Accepted Answer

A)   2.3â„¦
B)   1.84â„¦
C)   1.72â„¦
D)   2.87â„¦E) All of the above
F) A) and C) B

Exam 9: Electrical-Installations

The maximum tabulated Zs for a protective device as shown in BS 7671 is 1.44â„¦, the maximum permissible measured Zs will be