trying to answer a 2394-5 testing question help please

[guy 73]

Q The earth fault loop impedance for three of the final circuits were

L1.1 0.61 ohms
L1.2 0.42 ohms
L2.3 0.21 ohms

determine, showing all calculations, whether these circuits comply with BS7671

the scenario I have stats measured Ze 0.08 all at 20c
do I have to do something with 80% 0.08 rule of thumb ??

 

[GMES]

Guy may I suggest a little Hello from you and maybe a brief description of your qualifications etc, just to help the members Tailor their replies accordingly.

 

[Richard Burns]

As a new user I think your posts have needed to be moderated so are arriving delayed.
Your first post had missing information.
This post does not have enough information for us to answer directly, however you are on the right lines with the rule of thumb. (0.8 not 0.08 btw), the maximum values of EFLI in BS7671 are given for 70°C, Ze is irrelevant in this case as it is part of the EFLI value measured on the three circuits.

 

[GMES]

Richard you're right his first 5-6 posts need to be approved, I will keep my eye on the thread to try and keep it up to speed.

 

[Farmelectrics]

Have a good read of gn3

 

[SirKit Breaker]

Q The earth fault loop impedance for three of the final circuits were

L1.1 0.61 ohms
L1.2 0.42 ohms
L2.3 0.21 ohms

determine, showing all calculations, whether these circuits comply with BS7671

the scenario I have stats measured Ze 0.08 all at 20c
do I have to do something with 80% 0.08 rule of thumb ??

You need to provide the protective device type and rating, so you know which table to look at in BS7671 before you can work out if it is compliant or not.

Cheers...............Howard