Good morning folks, how deep should 4

First, this is the student section, where engineering students can get help for school problems and projects.

Second, this site isn't for providing free engineering services. If you need engineering services that are outside your area of practice, hire someone to design it.

Third, even if someone were inclined to provide guidance for your project, did you really expect accurate answers without giving any usable information?

In questionable ground, piles should be driven to refusal.


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Ohm's law
Not just a good idea;
It's the LAW!