High zs on low bay lighting circuits

[Krispy_88]

And that's why type D aren't the best idea when type C is available.

Isn't a C type 0.87? I might be wrong I've just done it on my calculator rather that check the regs. But it would mean a C type wouldn't work for one of them results. Could always drop to a 16A type c maybe if they are 2.5mm's...that'll give you 1.09. D types are awful, avoid like the plague. All depends on the load you have on the circuit really, shame they didn't record it.

 

[Ian1981]

Max zs on a 20 amp type c is 1.09 or 0.87 80% rule of thumb

 

[Octopus]

Think we need far more accurate information before we can give advice .....

 

[Ian1981]

Other options for high zs would be rcbos tho may have problems with nuisance tripping or localised supplementary bonding of the lighting circuits

 

[Dannyg8810]

Isn't a C type 0.87? I might be wrong I've just done it on my calculator rather that check the regs. But it would mean a C type wouldn't work for one of them results. Could always drop to a 16A type c maybe if they are 2.5mm's...that'll give you 1.09. D types are awful, avoid like the plague. All depends on the load you have on the circuit really, shame they didn't record it.

Yes sorry your correct ,so one of the circuits would still be over

 

[Des 56]

Are the fittings fused internally

 

[Dannyg8810]

Are the fittings fused internally

Low bays usually have a fuse at the terminals so more than likely yes

 

[Des 56]

Low bays usually have a fuse at the terminals so more than likely yes

Asked only because of 559.6.1.6

 

[Toneyz]

From past experience it has been the inrush start current that has been the problem on higher wattage low bay fittings so it may be interesting to know how many fittings being switched on at one time on each MCB.It will also be interesting to know Zdb and r1 +r2 and how much any parallel path of say structural steel is playing. Installing a RCBO may be the answer .