Max Zs by BS7671 HELP PLEASE

[James Sutton]

Hello All

Need some advice on the max valves by BS7671.

When filling out test sheets theres a column that requires the maX Zs valves from the regs i also note the valve from the regs book pg 48 49. I do the calculation of x 0.8 and match that against my measured Zs on the cct. Is this wright or wrong.

Thanks

JS

 

[ezzzekiel]

Enter max values as stated in brb

 

[keniff]

As above, put the values in from the bgb but in reality I work to the 0.8 rule for max figures to ensure tripping time

 

[mpspark]

Why enter the max values from the BRB rather than the actual measured value?

 

[James Sutton]

Ok thanks for ya help lads i do the calculation with the 0.8 and check against the valve from the regs.

 

[keniff]

Why enter the max values from the BRB rather than the actual measured value?

On my Certs you have to enter the measured zs reading and the max zs permissible for the protective device of the circuit

 

[ezzzekiel]

Why enter the max values from the BRB rather than the actual measured value?

Certs ask for both the max allowed and actual via calc or measurement but the op is refering to what he needs to enter for max values or max values adjusted for temp

 

[keefy]

OK I may be missing something here but what is the BRB?

 

[topquark]

OK I may be missing something here but what is the BRB?

BRB=Big Red Book ie BS7671:2008
BGB= Big Green Book (the above + ammendment one).

 

[ringer]

It is about to be replaced by the BGB

Seriously, the Big Red Book, soon to become the Big Green Book is BS7671 (IET Wiring Regulations)