Have you done any service work lately, and noticed a spark as you connect or reconnect the grounding electrode conductor to the ground rod of what appeared to be a perfectly normal electric service?

Article 215 covers the installation, conductor sizing, and overcurrent protection requirements for feeder conductors. The requirements for feeders have some similarities to those for branch circuits.

ORDINARY electric conductors are sources of spontaneous fluctuations of voltage which can be measured with sufficiently sensitive instruments. This property of conductors appears to be the result of ...