NEMA contact ratings are how much
current
Currents, Current or The Current may refer to:
Science and technology
* Current (fluid), the flow of a liquid or a gas
** Air current, a flow of air
** Ocean current, a current in the ocean
*** Rip current, a kind of water current
** Current (stre ...
at a rated
voltage
Voltage, also known as electric pressure, electric tension, or (electric) potential difference, is the difference in electric potential between two points. In a static electric field, it corresponds to the work needed per unit of charge to m ...
a
relay
A relay
Electromechanical relay schematic showing a control coil, four pairs of normally open and one pair of normally closed contacts
An automotive-style miniature relay with the dust cover taken off
A relay is an electrically operated switch ...
or other pilot device can switch. The current rating of smaller
NEMA
The National Electrical Manufacturers Association (NEMA) is the largest trade association of electrical equipment manufacturers in the United States. Founded in 1926, it advocates for the industry, and publishes standards for electrical product ...
contactors or their auxiliaries are defined by ''NEMA ICS 5: Industrial Control and Systems, Control Circuit and Pilot Devices''
standard. The nomenclature is a letter followed by a three-digit number, the letter designates the current rating of the contacts and the current type (i.e., AC or DC) and the number designates the maximum voltage design values.
AC Contact Ratings
DC Contact Ratings
{, class="wikitable"
, -
! Contact Rating Designation !! Thermal Current !! Voltage , , Voltamperes
, -
, N150 , , 10 , , 150 , , 275
, -
, N300 , , 10 , , 300 , , 275
, -
, N600 , , 10 , , 600 , , 275
, -
, P150 , , 5 , , 150 , , 138
, -
, P300 , , 5 , , 300 , , 138
, -
, P600 , , 5 , , 600 , , 138
, -
, Q150 , , 2.5 , , 150 , ,
, -
, Q300 , , 2.5 , , 300 , ,
, -
, Q600 , , 2.5 , , 600 , ,
, -
, R150 , , 1 , , 150 , ,
, -
, R300 , , 1 , , 300 , ,
See also
*
Utilization categories
In electrical engineering utilization categories are defined by IEC standards and indicate the type of electrical load and duty cycle of the loads to ease selection of contactors and relays.
Definition
The utilization categories category for low- ...
References
Relays
NEMA standards