Industrial electrical
Electrical Power & Protection replacement guide
Identify contactors, starters, overloads, circuit breakers, fuses, disconnects, transformers, power supplies, relays, surge devices, and distribution components by electrical ratings and approvals.
Evidence boundary. Electrical replacements can affect protection and equipment listing. A matching amp or voltage rating alone is not enough; verify interrupting capability, trip characteristics, controls, terminals, and approvals.
Items covered01 · 15 component types
- Circuit breakers
- Fuses
- Disconnect switches
- Contactors
- Motor-protection devices
- Control transformers
- Power transformers
- DC power supplies
- Uninterruptible power supplies
- Surge-protection devices
- Power relays
- Terminal blocks
- Electrical enclosures
- Power-distribution blocks
- Grounding components
What to capture02
Manufacturer, complete catalog number, poles, frame, and revisionRecord this before searching for a substitute.
Voltage, current, frequency, interrupting or short-circuit ratingRecord this before searching for a substitute.
Coil or control voltage and auxiliary contactsRecord this before searching for a substitute.
Trip curve, overload class, fuse class, protection settings, and coordinationRecord this before searching for a substitute.
Mounting, terminal, enclosure, approvals, and system groundingRecord this before searching for a substitute.
What must match03
Voltage, current, frequency, and interrupting ratingConfirm it against the original equipment, duty, and source documentation.
Protection curve, coordination, and application classConfirm it against the original equipment, duty, and source documentation.
Coil, control, auxiliary contacts, and communicationConfirm it against the original equipment, duty, and source documentation.
Mounting, terminals, dimensions, and enclosureConfirm it against the original equipment, duty, and source documentation.
UL, IEC, hazardous-location, and equipment approvalsConfirm it against the original equipment, duty, and source documentation.
Common searches04
What contactor replaces this part number?
What circuit breaker replaces this model?
Can I substitute a fuse with the same amp rating?
What transformer or power supply replaces this unit?
Authoritative starting points05
Source-backed field guides1 guide