earth fault loop impedance

[LankyWill]

R1+R2= Zs-Ze

Tin hat on

 

[Ian1981]

R1+R2= Zs-Ze

Tin hat on

Get that tin hat on mate tight I'd say because that's a no no :mtongue:

 

[westward10]

It was all going so well

 

[Dave OCD]

That 6a circuit must be a heck of a long run !

 

[DeGorsk]

that hurt my brain!

The reason I am asking is I am having a go at a practice theory question, which is:

1. The following measured values of loop impedance were recorded for six circuits in an installation. Each circuit is protected by a BS EN 60898 type B cb. Referring to the maximum tabulated values given, show by calculation if these measured valus are acceptable.

2. For any circuit that does not comply, suggest a method of overcoming the situation.

Measured impedance values in ohms:

CT1 CT2 CT3 CT4 CT5 CT6
40A 32A 32A 20A 16A 6A
0.5 1.25 0.96 1.62 2.0 7.3

Maximum tabulated values in ohms (BS7671)
1.15 1.44 1.44 2.3 2.87 7.67


And I am confused!

I have beer in my fridge...maybe I should have one!

Hi Gary,
Did you sort this? I am currently in the same conundrum? I do appreciate this was a long time ago for you..