True or False: Overload relays have many classifications; a few examples are Thermal, Magnetic, energy-saving, normally open (NO) relays, normally closed (NC) relays.

• A. True
• B. False
• C. Not sure
• D. Cannot be determined

Answer: (B)

Overload relays are classified by how they sense current and trigger a trip, not by contact configuration. The common categories are thermal overload relays, which use a bimetal strip that bends with heat from overcurrent; magnetic overload relays, which use a magnetic coil to actuate the trip; and electronic or solid-state overload relays, which monitor current with electronics and trip when limits are exceeded. Some designs even combine thermal and magnetic elements for faster or more reliable protection.

The statement mixes terms that don’t fit as standard classifications. Normally open and normally closed refer to the contact arrangement of a relay, not to the type of overload protection. Energy-saving is also not a fundamental classification of overload relays; it’s more of a marketing feature or a characteristic of certain motor starters rather than a primary category of overload protection.

So the best answer is that the claim is not correct because overload relays are categorized mainly by operating principle (thermal, magnetic, electronic), while NO/NC and energy-saving describe other aspects that aren’t standard classifications for overload relays.