I have carried out wiring for lighting in a shed in
Industrial area which contains Metal halide lamps & have
balanced in 3ph.Now when we put all the lines on in the
daytime the current taken at 3phases at MCB comes to be
equal i.e.28,29,28Amps respectively but in the night time
i.e between 7p.m.to 11p.m. at the same MCb the current is
52,59,62Amp, though I have fit 63A MCB it is tripping in
the above period.What may be the reason.?
Note: This industry is located in industrial area where
majority of steel ingot manufacturing plants are there.
Whether this may be due to harmonic? what should I do to
overcome above problem.pl suggest urgently.

Answer Posted / k.prakashchandra

You should allow 5% to 10% tolerance for MCB and
meters.There could be temporary additional load also.

Is This Answer Correct ?    0 Yes 0 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

If Polarization index of motor 8.75 at 500volts of medium voltage 4.16 KV motor what this mean winding good or bad pl answer if any reffrence book give me the link

1699


A double circuit with dog conductor 66KV Transmission line from wind farm evacuation to feeding substation having capacity of 25MW for transmission. Can same transmission network be considered for further expansion of Power & how much in MW. If we need to expand next 10-15 MW more will there any augmentation is required in transmission network? Kindly reply asap.

1660


we all know voltage is a force(emf), and the force always devides if 2 or more than2 loads are there but why does the voltage remains same is parallel, it must devide na ???

1487


What is the procedure/activities to be taken to inject the current more than 2000A by using 2000A Loading Transformer?

1534


SUTIABLE FOR ohm's law super conductor

1500






what is magnetizing current test in power transformer

2140


how to calculate short circuit current for the busbar

924


direction of tarbine& genrator

1596


how is the testing of an REF relay? what are the test REF circuit having?

1435


I am getting above 60 V as open delta voltage against single phase unit ICT at tertiary delta formed and ICT getting trippped on NDR. ICT tested and found in order. PTs provided on tertiary are tested and in order. what may be the reason?

1488


What will happen if the d.c. Shunt motor opened accidentally running on no-load has its shunt field winding?

856


How to Decide(calculate) Bush bar size for copper and aluminiam ?

1670


Dear sir, I completed DECE In the year 1995.Now i am working in a private company from last 10 years as an Electrical supervisor.The company having a 1000 KVA transformer.Now i try to apply "C" Licence. I am eligible or not.If not eligible,pls give solution.

1254


hi this is hema, r there any books in particular for the preparation of the APPSC-A.E.E(electrical), if so please mail me the names ... thank u .

1468


why capacitive load is not used in routine life????any reason is there ??????

1112