# IEEE C37.16-2009 pdf free

**IEEE C37.16**-2009 pdf freeIEEE Standard for Preferred Ratings,Related Requirements, and Application Recommendations for Low-Voltage AC (635 V and below)and DC (3200 V and below) Power Circuit Breakers.

3.3 Rated power frequency

Thc prcfcrrcd rated power frequency is 50 Hz, 60 H, or 5060 Hi.

3.4 Frame size

The frame size should be one of the following values: 600 A, X00 A. 1600 A, 2000 A, 3000 A. 3200 A, 4000 A. 5000 A. or 6000 A.

3.5 Rated continuous current

The rated continuous current is defined by the trip device current settings. see clause 6. The continuous- current carrying capability of some circuit breaker frames may be higher than the trip-device current rating (see IEEE StdC37.l3).

3.6 Short-cIrcuit current and short-time rating

3.6.1 Unfused circuit breaker frames

Table I provides the short-circuit current ratings, and the preferred ranges, for circuit breakers with instantaneous direct-acting tripping elements. Table 2 provides the short-time current ratings with instantaneous direct-acting tripping elements and the short-circuit current ratings fbr circuit breakers without instantaneous direct-acting tripping elements (intentional time-delayed tripping).

The short-circuit currents are given as mis symmetrical values for single-phase (2-pole) circuit breakers and three-phase average rms symmetrical values of three-phase (3-pole) circuit breakers. On systems where the voltage across a single pole exceeds 58% of the rated maximum voltage, the short-circuit rating shall be 87% of the three-phase value.

3.6.2 Fused circuit breaker frames

The rated short-circuit current is 200 kA.This rating is the rms symmetrical value for single-phase (2-pole) circuit breakers and three phase average rms symmetrical value of three-phase (3-pole) cireuit breakers. On systems where the voltage across a single pole exceeds 58% of the rated maximum voltage, the short-circuit rating shall be 87% of the threephase value.

Fused circuit breakers do not have a short-time current rating. Fuse current ratings may be 300 A, 600 A, 800 A, 1000 A, 1200 A, 1600 A, 2000 A, 2500 A, 3000 A,4000 A, 5000 A or 6000 A. Fuses shall be of the current-limiting type.

3.7 Power frequency withstand voltage The minimum power frequency withstand voltage of the primary circuit is 2200 V ac.

3.8 Overload and endurance The preferred ratings, related requirements, and application recommendations for endurance of low-voltage ac power circuit breakers shall be as given in Table 3, Table 4, and Table 5.IEEE C37.16 pdf download.