Editing Ground and neutral (section)

==Combining neutral with ground==

[[Stray voltage]]s created in grounding (earthing) conductors by currents flowing in the supply utility neutral conductors can be troublesome. For example, special measures may be required in barns used for milking dairy cattle. Very small voltages, not usually perceptible to humans, may cause low milk yield, or even [[mastitis]] (inflammation of the udder).<ref>Thomas J. Divers, Simon Francis Peek (ed),''Rebhun's diseases of dairy cattle'', Elsevier Health Sciences, 2008, {{ISBN|1-4160-3137-5}} pp. 389–390</ref>
So-called "tingle voltage filters" may be required in the electrical distribution system for a milking parlour.

Connecting the neutral to the equipment case (if permitted by relevant regulations) provides some protection against faults, but may produce a dangerous voltage on the case if the neutral connection is broken.

Combined neutral and ground conductors are commonly used in [[electricity distribution|electricity supply companies]]' wiring and occasionally for fixed wiring in buildings and for some specialist applications where there is little alternative, such as [[railway electrification system|railways]] and [[tram]]s. Since normal circuit currents in the neutral conductor can lead to objectionable or dangerous differences between local earth potential and the neutral, and to protect against neutral breakages, special precautions such as frequent rodding down to earth (multiple ground rod connections), use of cables where the combined neutral and earth completely surrounds the phase conductor(s), and thicker than normal [[equipotential]] bonding must be considered to ensure the system is safe.

===Fixed appliances on three-wire circuits===
In the United States, the cases of some [[kitchen stove]]s (ranges, ovens), [[cook top]]s, [[clothes dryer]]s and other specifically ''listed'' appliances were grounded through their neutral wires as a measure to conserve copper from [[copper wire and cable|copper cables]] during [[World War II]]. This practice was removed from the [[National Electrical Code|NEC]] in the 1996 edition, but existing installations (called "old work") may still allow this to remain in place. Canada did not adopt this system.

Using the neutral conductor for grounding the equipment enclosure was considered safe since the devices were permanently wired to the supply and so the neutral was unlikely to be broken without also breaking both supply conductors.{{Citation needed|date=May 2025}}