City & Guilds 2391/20 Exam

[steverido]

Hi,

can anyone help, I have a mock paper for the Design & verification course and a question has arisen as follows;

state on instance where it is permissible to increase the disconnection time of circuits supplying socket outlets to 5.s?

Thanks in advance

 

[johnboy6083]

is it if they are over 20A?

 

[Technicalguy]

under the 16th edition, you could increase the time to 5 seconds if you used a bigger cpc? under 17th 5 seconds is not permissible.

 

[Sintra]

230v final circuits in a TN system not rated greater than 32A must disconnect within 0.4 seconds under fault conditions. 411.3.2.2

Under fault conditions in a TN system, final circuits over 32A and distribution circuits must disconnect within 5 seconds. 411.3.2.3

 

[johnboy6083]

thanks for correcting me Sintra! Its amazing how much you remember/learn reading through threads. Its nice to learn fiorm other peoples experiences too!

 

[GStueyXR]

If the circuit supplies a fixed appliance only i think.

 

[vinny electric]

5 sec is on fixed appliance. and 0.3 sec on all others