Electric Motor Control Basics - Book - Page 80
NEMA vs IEC Motor Controls
Other Differences Between NEMA vs IEC
The primary difference between the two contactors is that NEMA provides for up to
25% service factor. IEC, on the other hand, focuses on space and cost-savings. It tests
components to their exact design IP rating, using utilization categories to rate items
according to their intended use.
As such, devices that operate below 100A or 50HP are going to be much larger for
NEMA and more expensive. IEC will also have more options for a power rating, making
it more critical than the NEMA ratings. This is where the contention lies in the United
States regarding the IEC system.
It’s also worth noting that NEMA addresses matters to do with the construction of
electrical elements. The standards are all about minimum design requirements for
enclosures. IEC is more inclined towards IP ratings.
NEMA addresses corrosion, something amiss with the IEC classifications. NEMA
also incorporates some level of protecting enclosures against corrosion. Sometimes,
NEMA ratings and IEC’s IP ratings don’t directly correspond, since they cover different
protections.
Industrial Control
Basics:
Part 1, Contactors
Industrial Control
Basics: Part 2,
Overload Relays
Industrial Control
Basics: Part 3,
Starters
The Benefits of Type E/F
Motor Protection
Circuit Breakers
Basic Pump Control:
Three Phase DOL Starter
Control of an Electric Pump
Applying Motor Control
in a Wastewater
Application
NEMA vs IEC Motor
Controls
Understanding
IP Ratings
80
