Calculation of ZS

[Jamie198]

Hi guys am I right in saying that if the circuit in question is protected by rcd/rcbo then there is no need for the multiplier. (table 41.5) really unsure about this. Any help would be good I've got my 2394 written tomorrow I've pasted the practical and multiple choice.

 

[Geoffsd]

Not sure what you mean.

If you mean the 0.8 correction factor for the temperature, it would hardly apply to 1,666Ω - would 1,333Ω be satisfactory for a circuit?

If you mean an RCD/RCBO means you can ignore the maximum Zs for the overcurrent protection device then - no, you are not right.

 

[Jamie198]

No I know you still have to check zs readings with those set in bs7671 I know that rot is 80% of regs readings. I'm talking about if cables are bunched or if temp is not 20degrees sorry for being unclear but iPhones and long explanations are a real bad mix

 

[Engineer54]

No I know you still have to check zs readings with those set in bs7671 I know that rot is 80% of regs readings. I'm talking about if cables are bunched or if temp is not 20degrees sorry for being unclear but iPhones and long explanations are a real bad mix

So is digging up threads that are 4+ years old!!

 

[Jamie198]

I'm new to this thought I might ask for some advice never knew I had to be up to date on the ways of forums it won't happen again

 

[Silly Sausage]

Take no notice of Eng54 Jamie, he's just woken up!

 

[Jamie198]

No notice taken. Just going to go with my gut tomorrow It's done me no harm this far