Generac Guardian Home Standby Generator Installation
April 12, 2006
Q: I am wiring my new home in a rural area where a city water system is not available. If a power outage occurs, there will be no water because an electric pump supplies water from a well. I am concerned, and I want to install a standby generator for the well pump and other loads. Where do I find requirements for the installation of a generator in the National Electrical Code (NEC)?
A: The NEC classifies this generator as an Optional Standby System in Article 702. The Article applies to permanently installed and portable generators that can be connected to a premises wiring system. In addition to the requirements in Article 702, you must also comply with the rules in Article 445—Generators. This Article requires overcurrent protection for the generator.
The feeder conductors from the generator terminals to the first overcurrent device must have an ampacity that is equal to or greater than 115 percent of the nameplate current rating of the generator. And live parts of generators operating at more than 50 volts to ground cannot be exposed to accidental contact.
Transfer equipment, either manual or automatic, must be provided to prevent inadvertent interconnection of the normal and standby power sources. This can be a transfer switch or double-throw safety switch with proper voltage and current ratings.
A sign is required at the service that indicates the type and location of the on-site generator. A sign is also required at the location where the generator grounded circuit conductor is connected to the grounding electrode system where this connection is remote from the generator.
However, there is no requirement to separately ground the generator grounded circuit conductor is this conductor is not switched in the transfer equipment. These rules are in 702.8(A) and (B).
If the generator grounded circuit conductor (neutral) is switched with the ungrounded conductors of the generator at the transfer equipment, a separately derived system is created and 702.10(A) requires compliance with 250.30. If the neutral of the generator is not switched, part (B) of 702.10 applies, and the generator equipment grounding conductor must be bonded to the system grounding electrode.
If the power goes out will you be ready?
No more worries of blackouts, brownouts or weather related outages. Just peace of mind that 24 hours a day, 7 days a week your home and family are protected against electrical failure.
• Fully automatic
• Permanently installed
• Runs off home’s fuel supply (Natural gas or LP)
• More practical than a portable
7,000 watts (7kW) – 45,000 watts (45kW)
Starting at $1997.00
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