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Subchapter 5. Electrical Safety Orders
Group 2. High-Voltage Electrical Safety Orders
Article 28. Rotating Machinery and Its Control Apparatus (Formerly Article 77)
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§2884. Generator Circuit Protection.

(a) Generator Grounding. Generator windings, if grounded, and frames shall be grounded in accordance with Article 6.

(b) General. The high-voltage circuit of each generator shall include coordinated protection capable of detecting and automatically interrupting overload and fault currents in the generator, the generator circuit conductors, and the generator control.

EXCEPTION: The overload protection for generators in supervised locations need not automatically trip the switching device, provided it initiates an alarm for the operator to take appropriate action.

(c) Fault Current Protection.

(1) Fault current protection shall be provided by one or more of the following:

(A) A circuit breaker, contactor, or other device meeting the requirements of Article 21.

(B) Fuses meeting the requirements of Article 23.

(2) Fuses used for fault interruption shall be placed in each ungrounded conductor. Circuit breakers or contacts and their associated fault sensing devices shall provide protection for, and shall simultaneously disconnect, all ungrounded conductors.

(3) For faults on the generator side of the generator switching device, the fault protection system shall automatically remove excitation from the generator.

(4) Fault interrupting devices in generator circuits shall not automatically reclose after trip.

(d) Overload Protection.

(1) Each generator shall be protected against dangerous overheating by one of the following means:

(A) A thermal protector integral with the generator.

(B) An external current sensing device.

(2) Overcurrent devices shall not be automatically reset if any hazard results.

(e) Combination Protection. Combination fault interruption and overload protection shall be permitted to be provided by the same device.

(Title 24, Part 3, Section 3-445-10.)

NOTE: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code; and Section 18943(c), Health and Safety Code.


1. Editorial correction filed 11-2-83 (Register 83, No. 45).

2. Editorial correction of section heading filed 11-3-83 (Register 83, No. 45).

3. Amendment filed 12-10-87; operative 1-9-88 (Register 88, No. 1).

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