Connect ground clip of o-scope probe to negative terminal of battery- is negative of battery now at earth V?

Question

If one connects the ground clip of an oscilloscope probe to the negative (or positive) terminal of a battery, is this terminal now effectively at earth potential?

Answer 1

Yes. The ground clip of a scope is usually connected to the chassis. The scope chassis is usually connected to the ground pin of the wall plug. The ground pin of the wall plug is connected to a ground wire that goes to the ground bus at the distribution box. From the ground bus in the distribution box, a ground wire goes to a grounding rod that is driven into the earth near the kW hour meter. No current is supposed to be flowing in any of the ground wires, so everything connected to them is effectively at earth potential.

Answer 2

No, to be at earth potential, you need a physical connection to Earth.

The NEC definition specifies a conductive pipe or rod driven at least 8 feet into the ground.

That would be at earth potential.

Answer 3

GROUND in a circuit means ZERO volts at that point,usually it also means the COMMON end of a circuit.

Electricity Ground is a real ground wire....it pitches at least a 6 feet copper pipe deep into the wet soil ground. Then connect it to the house breaker panel. This is GROUND ZERO volt for AC current that we use every day. The reason is.....electricity generator from the suppler bury one wire into the earth. Use our earth ground as a large piece of conductor to save the cost of installing million of real metal make ground wires. This  task only works for AC current.

A scope probe ground is connected to its circuit ground (common) where has a zero volt DC. This common also connect to the scope chassis and the real ground wire from the AC power plug. Now you connect this common to the negative of a battery. Therefore,it has the same ground zero volt DC refer to the scope.