transformer body n neutral connections

Neutral should have two earth pits exclusively .If its a star /star Trf then both primary and secondary neutrals should have two each making a total of 4.These can be connected to the grid as well.

Hi

earthing is earthing, only the thing behind to have more than one earthing point is reliability,

the earthing must have minimum resistance. yes for small trans. if neutral is directly earthed then the same earthing point can be used for body earthing too, but in case of big size trans. where neutral is grounded through impedance or resistance, the length of body eathing increases that time, so better to use separate earthing pit which will provide minimum resistance path for body,

You can also ensure that the resistance between two different earthing pits in your company is having almost negligible resitance, so both are redundunt.

Best regardss

divyesh patel

what should be the minimum distance between two earth pits? and why to maintain the distance. please guide.

In India It is mandatory as per IE rules that u have 2 neutral earth pits exclusively which can also be connected to the earth grid .Body earthing needs separate pits.Earthing does not receive as much attention as one would desire.It may never be in use in its life time.but if and when a fault occurs it should be in condtion.

Dear Divyesh,

You are absolutely right that Earthing is Earthing anyway, but it's role changes when it comes to any critical equipment like Transformers, Generators etc.

When Transformers,Generators neutral is intentionally earthed through inductor or

resistor, it is called Neutral Grounding not Neutral Earthing.

Grounding is done for Equipment Safety.

Earthing is done for human-creature life safety.

Both pits should not be mixed as their purpose differs.

Grounding bus is always online but Earthing bus/strip energized while leakage of current at body.

Regards,

Substation 15.