MCC Ground Fault

Exactly what it says on the tin: it is an unwanted connection from phase to ground/earth or neutral to ground/earth, or anything else to ground/earth for that matter.

• The cause of one that happened here turned out to be a woodscrew holding an earthed metal fitting to a wooden post. That particular screw had found a previously-undiscovered cable buried in the plaster of the wall, and had pierced the insulation and just kissed the neutral conductor on its way into the post. Every time the bothy's load exceeded about 6kW, the incoming 100mA RCCD tripped the place into darkness. It took days to find that bu&&er!

All of the usual suspects seem rather squirrelly today.

I think the real question was "What are the common causes of ground faults?" maybe?

Would one of the censors moderators clean this up, please?

Ooops..

Meant to state

what are the common causes of ground fault?

Ground is weathered rock. So ground is caused by rain erosion, wind erosion, frost pry, followed by one of the above, rivers and finally man.

I'm sure there are more causes of ground, but I'm bored.

Since there is no way to determine a "topic" from the disjointed OP, I'm sure this response can't be marked OT.

_{Where have all the intelligent questions gone?}

Bad ground faults in the MCC are usually blamed by the umpire on persistent precipitation in the Marylebone district of London.

Common causes of ground faults then?

Electrical conductors coming into contact with the earth (ground, ground up rocks, whatever). Everything else is a sub-set of that

1. Insulation failure (lots of sub-sets of that)
   
2. Mechanical damage to equipment (lots of sub-sets of that)
3. Liquid incursion (lots of sub-sets of that)
4. Human error (lots of sub-sets of that)
5. Pest infestation (lots of sub-sets of that)
6. Any combination of the above (lots of sub-sets of that)