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How to Ground a Home Generator
©Copyright Dave Rongey - Summary:
Grounding a Generator and the Home Electrical System: The Importance of a Generator Transfer Switch, Generator Questions and Answers.
Grounding a Home Generator
Electrical Question: I have a 5500 watt generator I use as stand alone with extension cords inside off of the 2 GFCIs on the generator.
The Outside Wall Has a Male Connection Receptacle L14-30p.
- I run thru a pass thru in the kitchen wall. On the inside wall is a 30Amp fused disconnect which then goes to an outlet box containing my L14-30r. Then from L1430 the power goes to my two GFCIs, then 120 volt extension cords. I have no desire to ever use a transfer switch and yes am fully aware never to BACK FEED branch circuits. In emergency I only want power for refrigeration, a small appliance and use the internet and two lights.
- My question is about grounding. I run a #6 ground from the generator’s ground lug THRU AN OUTLET BOX on the outside into my basement and tied it with a Burndy into my Grounding electrode system #6 to a water pipe and 2 ground rods. Is this best? Would it be better to drive A SEPARATE Ground Rod at the generator?
- My current reservation is that in the event of a lightning strike to the generator am I “inviting” the strike into my home’s GES, Grounding Electrode System? Thus a separate rod might help somewhat? Might avoid a hit to my GES with a separate ROD?
- Also in the event of a fault inside the generator how does the fault clear…If a fault doesn’t trip the breaker could the ground (GES) become energized & back to the utility neutral/transformer. Thus would it be better to either use a separate ground rod or my GES? I am aware that the generator’s frame is a ground. Am I over doing this by grounding to GES or separate rod?
- Lastly,another concern on my set up: Would any current in the event of a fault or lightning strike possibly get back to the electric utility pole transformer in addition to passing to ground thru my home GES. Thus making a separate rod a better choice?
Thanks for your availability & patience in helping. I have yet to find an example of anyone using my exact set up on-line and really would like to know if I should change anything.
This home electrical repairs question came from: Charlie, from Boston, Massachusetts.
Thanks for your electrical troubleshooting question Charlie.
Grounding a Generator and the Home Electrical System
Skill Level: Advanced – Licensed Electrical Contractor, Not Recommended for Homeowners.
Tools Required: Electricians pouch of hand tools and the various power tools necessary for installing the generator and transfer switch.
Estimated Time: Depends on the type and size of the generator and transfer switch and the available access to the project area.
Important: Installing a generator and transfer switch or altering the home electrical system must be well thought out and performed with a permit with all work being inspected.
Bonding the Home Ground Electrical System
- Installing an additional ground rod would not be necessary, but bonding the generator ground to the main home electrical ground system is highly recommended even with a stand alone generator where it is not tied into or not connected to the home electrical panel but instead the generator power is provided using approved extension cords for temporary power.
- In the event of a lighting strike, the strike will take the path of least resistance to the earth ground which should always be the home electrical ground system which has been installed according to applicable local and national electrical codes.
- The path and power of a lightning strike is unpredictable due to many environmental factors, however the required home GES is the best way to direct the lighting strike to the earth ground. This will also help prevent the lightning strike from traveling back to the utility transformer power pole.
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