445.11 Generators. Marking.
Code Change Summary: Code language was added to require additional markings on the generator from the manufacturer.
One of the new marking requirements will make it easier to determine in the field if a generator is wired as a separately derived system. Knowing this determines what type of transfer switch to install and where to locate any required grounding electrodes per 250.35 and 250.30.
When the inspector arrives for the generator inspection, several things will be considered:
- If the system is being used as an emergency system, legally required or an optional standby system.
- Type of transfer switch being used to ensure it is compatible with the type of generator system.
- Whether or not the generator is wired as a separately derived or non-separately derived system and the location of any system bonding jumpers that may be present.
Often when trying to determine if a system bonding jumper is installed, the electrician will end up removing multiple covers from the generator while trying to find the right compartment where a system bonding jumper may be located.
Now, the 2014 NEC® requires the manufacturer to mark the generator to indicate whether or not the generator neutral is bonded to the generator frame.
Below is a preview of the NEC®. See the actual NEC® text at NFPA.ORG for the complete code section. Once there, click on the “free access” tab and select the applicable year of NFPA 70 (National Electrical code).
2011 Code Language:
445.11 Marking. Each generator shall be provided with a nameplate giving the manufacturer’s name, the rated frequency, power factor, number of phases if of alternating current, the subtransient and transient impedances, the rating in kilowatts or kilovolt amperes, the normal volts and amperes corresponding to the rating, rated revolutions per minute, insulation system class and rated ambient temperature or rated temperature rise, and time rating.
2014 Code Language:
445.11 Marking. Each generator shall be provided with a nameplate giving the manufacturer’s name, the rated frequency, the number of phases if of ac, the rating in kilowatts or kilovolt-amperes, the normal volts and amperes. corresponding to the rating, the rated revolutions per minute, and the rated ambient temperature or rated temperature rise.
Nameplates for all stationary generators and portable generators rated more than 15 kW shall also give the power factor, the subtransient and transient impedances, the insulation system class, and the time rating.
Marking shall be provided by the manufacturer to indicate whether or not the generator neutral is bonded to the generator frame. Where the bonding of a generator is modified in the field, additional marking shall be required to indicate whether the generator neutral is bonded to the generator frame.
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445.11 Generators. Marking.
Below is a Real Question from our Electrical Continuing Education Courses for Electrical License Renewal:Which of the following is required when the bonding of a generator is field modified?
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