New to the forum grid tie with a backup generator question

[greatlakes08]

I currently am setup with a grid tied 10kw system with no battery backup. I was able to get a great deal on a propane genset and want to connect it into my system. The generator is a Kohler 8RESVL. The brochure for the generator says that if it is used with propane it will run at 8kw and 33.3 amps at max load. I am needing help deciding what size breaker to use in my service panel and if I should use 10 or 8 gauge wire. From what I have found online 10 gauge wire is sufficient with a 30 amp breaker but wouldn't this be an issue if the generator is running at max load or power spikes when a large consumer comes online causing the breaker to trip? Please feel free to put this in the appropriate forum if needs to be moved.

[bob-n]

This may be a question better for an electrician than solar people. I am not an electrician. But that said, check out this link:

https://www.norwall.com/product_pdfs/5890_8resvl.100lc12_install.pdf

This is the installation guide for your generator. On page 18, it talks about breaker and wire size.

[greatlakes08]

Thanks for the reply....I have looked at the manual and the chart. The chart refers to temperatures and then refers you to the NEC. I figured I would ask on the forum hoping an electrician would chime in to save me some time looking.

[Ampster]

If you think there is a chance for large spikes or running at full capacity then go with 8 Ga wire and the correct breaker. It is more of a risk management issue than an electrical issue, especially if the manual says 10Ga. If you ask an electrician he will say 8 GA because he doesn't want to be called if the breaker trips. I am no an electrician. I usually update wire if distance is long to avoid voltage loss. I evaluate loads and make decision based on that.

[Mike90250]

I currently am setup with a grid tied 10kw system with no battery backup. I was able to get a great deal on a propane genset and want to connect it into my system. The generator is a Kohler 8RESVL. The brochure for the generator says that if it is used with propane it will run at 8kw and 33.3 amps at max load. I am needing help deciding what size breaker to use in my service panel and if I should use 10 or 8 gauge wire. From what I have found online 10 gauge wire is sufficient with a 30 amp breaker but wouldn't this be an issue if the generator is running at max load or power spikes when a large consumer comes online causing the breaker to trip? Please feel free to put this in the appropriate forum if needs to be moved.

10ga is rated for 30A, I would use 8ga simply to reduce the losses. I would use 30A breaker and insure your loads will not surge and trip the breaker. The generator will also have an internal breaker, and you don't want that to become the first to go. (breakers wear out and the odd format used in each brand are hard to find replacements for)

[Ampster]

Thanks for the reply....I have looked at the manual and the chart. The chart refers to temperatures and then refers you to the NEC. I figured I would ask on the forum hoping an electrician would chime in to save me some time looking.

The NEC has a 125% rule for continuous loads.

[greatlakes08]

Thanks everyone for the answers. I will run the 8 ga and the 30 amp breaker as Mike suggested. Knowing that the breakers on the generator are unique is very helpful thank you.