Multiple reference methods

[gazdkw82]

Just practising filling out paperwork for upcoming assessment. Come to abit of a stumbling block.

There are x2 3 phase circuits that have more than 1 method of installation.

Which reference method do you list on the schedule of tests results?

Also, for max Zs of the operating device, are the values just the usual values listed on pages 61-63 of the regs? Doesnt matter if it's a 60898 16a type c 3 phase or single phase? It's still the same value?

 

[gazdkw82]

Anyone got any ideas on this?

 

[Ian1981]

Choose the most onerous reference method as this will ultimately determine the Iz of the cable.

Zs values regarding ocpd’s for 3 phase and single phase are the same.
A C type 16 amp mcb has a max Zs of 1.37 ohms for a linked 3 pole mcb and a single pole mcb

 

[SparkyChick]

As @Ian1981 says you should pick and record the method which presents the worst case scenario (i.e. the lowest current carrying capacity).

The same logic will be applied to most of the paperwork... lowest IR readings, highest Zs values, slowest trip times etc. since you need to know the installation will perform as required in the worst case.