no and no.......... You take a DMM and a long piece of wire. Set DMM to read ohms. Measure resistance of the wire, put one probe on each end. Now connect one end of the wire to battery NEGATIVE. Put one probe on the other end of the wire, the other probe on the spot you want to test. Subtract the reading you got from the wire from the reading you get now. If you come up with almost 0 you've got a good ground.