mtnelectrical
Senior Member
- Location
- Essex, New Jersey
When does a portable generator need to be grounded?
Grounding Portable generator
- Thread starter mtnelectrical
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kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
250.34 answers your question.
When supplying equipment on the generator or receptacles on the generator is the main rule - and the grounding terminals are bonded to the generator frame. (note it does not mention the generator neutral needing to be bonded to anything)
When supplying equipment on the generator or receptacles on the generator is the main rule - and the grounding terminals are bonded to the generator frame. (note it does not mention the generator neutral needing to be bonded to anything)
mtnelectrical
Senior Member
- Location
- Essex, New Jersey
and when it comes to sizing the grounding conductor, we use the wattage of the gene or to the amps of the receptacle?. I have just 2 15 amps 120v receptacles on the gene and it is a small gene of 2000 watts
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
If the conductor is a grounding electrode conductor you size it according to 250.66 which is based on ungrounded conductor sizes.
If the conductor is an equipment grounding conductor you size it according to 250.122 which is based on overcurrent device setting.
- Location
- Illinois
- Occupation
- retired electrician
In the older codes where the term "grounded" was defined as having a connection to earth or some conductive object that serves in place of the earth" there was no issue as you could have a grounded system by bonding to the generartor frame. Now that "grounded" is defined as "connected to the ground or a conductive body that extends the ground connection" the output of a generator is not a "grounded system" unless it is connected to a grounding electrode, and cannot be used for any system that is required to be grounded.
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