how to calculate no. of earthing pits and their diamensions?
no. of lightning arrester rods which are required to
protect a building of 35 mtr and we calculate?
- 5 Answers
- 26622 Views
- Dharampal Premchand Limited, FlowMore, Hindustan Zinc, Ispat, Maheshwary Ispat, NDDB, Siemens, I also Faced
- E-Mail Answers
Answer Posted / william lobo
The number of earthing pits depends on the soil resistance.
We may require earth resistance of 1ohm or 3 ohms at the
most. To get this we will have to install at least 2 pits
and as per parallel formula i.e. 1/r1+1/r2+1/r3= 1/R. We
have to keep on increasing the number of earth pits till we
get the required value for R=1 or 3 as per requirement.
| Is This Answer Correct ? | 14 Yes | 6 No |
Post New Answer View All Answers
What is different between resistance grounding system and resistance earthing system?
What is the drawback of class b amplifier?
1))why we run three phase or three different circuit from a single conduit 2)) why not two circuit of different phase run in same conduit?? and why we run same three cicuit of same phae run in single conduit??
What happen if we apply square wave or traiangular waveform voltage to the transformer primary winding instead of sinusoidal wave?
what is the step by step formula for calculating bus bar phase and neutral size of a panel board.suppose the incomer of panel board is 100A..???step by step answer please
How to calculate the time setting for star connection in star delta starter? For example 10KW 3PH Induction motor.
Name the types of motors used in vacuum cleaners, phonographic appliances, vending machines,refrigerators, rolling mills, lathes, power factor improvement and cranes.
WHAT IS THE CURRENT CARRYING CAPACITY OF 2.5/3 CORE HI TUFF CABLE,WILL IT SAFLEY CARRY 8.6 AMPS OVER 120 METRES,CAN YOU ALSO ANSWER WITH FORMULA FOR WORKINGS OUT ,THANK YOU 3RDYR APPRENTICE.
for a 400kv t/m line with 10 ampere current will corona occur?
xpression 'document.FrmQF.myemail' [
what heppend if we are connected u1-v1-w1 as a star point in the place of u2-v2-w2 in power genration
How do we calculate the Out put voltage of generator, after the excitation is being given?
What is the Current equation in series RLC circuits.
1)what is the function of a frequency inverter? 2)If a few frequency inverter are connected onto a device network,what are the two setting that will ensure the frequency inverter work properly on the network. 3)whats is the name of the input sensor for weigher? 4)How to confirm that the load cellis faulty? 5)Describe briefly the steps to validate that the weigher is working properly? 6)Describe the procedure to validate the flowmeter accuracy? 7)Describe briefly the steps to validate that the tempreture sensor/transformer is working properly. 8)what is the adjustment that need to be done when you are calibrating the temperature transmitter ? 9)what are the safety measures to be taken before disconnecting motor for rewinding. 10)whats is the synchronous speed in rpm of typical 4pole 50hz motor? 11)whats is the formula for kw, ohm's law 12)if a 3phase motor is rated 3kw,415vac,what is it's rated ampere?
What is the phase relationship between the primary and secondary voltages of a transformer?
