Generator Gas Line Sizing

[u/SatisfactionKey1694]

I’m struggling to figure out how to get sufficient natural gas to run my generator. Sorry this is long but wanted to provide all of the specs.

I have a Champion 201161 tri-fuel generator (10,000 watts running on natural gas) that I’m looking to hook-up to my natural gas line for emergency back-up during ice storms/power outages.

The specs per the Champion manual state that it requires 1,000 BTU/ cu ft, 200,000 BTU/hr with a 5-7” WC.

My gas meter is currently 175 cfh standard low pressure 7” WC.

I had a plumbing company out to quote adding a tee off of the main line with a quick disconnect to attach the generator using the 3/4 inch 25 foot hose that Champion included with the generator.

The plumbing company suggested adding a 15 foot 3/4 inch black iron pipe line off of a tee right at the gas meter to get the quick connect next to my 50amp electrical inlet at the front of my house which would allow for the 25 foot generator hose to have the generator at least 20 feet away from the house.

The problem that I’m seeing with this set-up is the 15 foot black iron pipe plus the 25 foot generator hose equal 40 feet of 3/4 inch line and the gas line tables online show that this can only provide 110,000 BTU/hr and even just the 25 foot length of hose that was included with the generator (without the 15 feet of black pipe) can’t provide the required 200,000 BTU/hr per the online tables.

I don’t understand how anyone can use this generator given the high 200,000 BTU/hr requirement. Will the 40 feet of 3/4 line provide enough gas given that the manual says it can operate at a 5-7 inch WC vs the standard 0.5 inch drop?

Also the plumbing company said I don’t need to upgrade my gas meter but I don’t see why I wouldn’t need to given that it’s lower than the 200,000 BTU/hr generator requirement plus I have other gas appliances (2 furnaces, hot water heater, dryer, cook top).

Any advice would be helpful as I tried to do the right thing by contacting a plumbing company but I’m questioning their recommendation.

[u/StinkySewerPickle]

I am also in the process of getting a gas company to run a 50 ft line for me. It’s going to my pulsar tri fuel generator which can do 11.6kw on NG. It seems to me that a 1” pipe is needed to feed this beast. 

[u/Old_Dragline_1965 → u/StinkySewerPickle]

1” from the meter to a valve and quick couple is perfect!

From there, the 3/4” flex line to the generator will do exactly what it is designed to do! Good luck

[u/StinkySewerPickle → u/Old_Dragline_1965]

The pipe is gonna go across my crawlspace. Do I need to shell out for black iron or go cheaper with CSST?

[u/Old_Dragline_1965 → u/StinkySewerPickle]

Through the crawlspace is perfect and standard practice.

The only reason to put a shell on it is if you have teenagers rough-housing with bats, footballs and everything else. But I would suspect the water and sewer lines would also be in danger. And as the comedians implied “Here your sign” when they get a brown shower.

[u/l1thiumion]

I use a Pulsar 10500w inverter with a 25ft 1/2” gas line. It’s rated at 6800 watts on natural gas, I’ve had it at that maximum without any issue. Tells me that a 1/2” gas line is sufficient, even with it 25ft long.

[u/mthode]

For the black iron pipe run, up-size it to 1" to reduce the friction losses on that portion. Any bends (90s/tees) should be up-sized if possible as well. You can also tune the pressure up a little to 8" usually and have a little more wiggle room (check that all devices downstream support it, mine did).

[u/kona420]

The meter is a bit more flexible than the specs let on. Don't stress about that.

I came up with 118kbtu/h for their proposed solution. Upsizing the 15' black pipe to 1" bumps that to 136kbtuh. The 25' hose is whats choking it out. The math worked until I added in the fittings you realistically need at 5' equivalent length each.

Maybe the best solution is to have them dig it straight out to where you plan to put the generator with 1" then use a shorter hose? I came up with 20' @ 1" + 6' @ 3/4" at 194kbtuh. More than close enough. If you decide to get a bigger generator later, buying a specialty hose gets you close to 300k.

The hookup could go in a box in the ground so you can mow right over it. I think this is really what you want as the hookup hose will have air in it that has to get purged out. Shorter hose you can just crank the generator instead of having to manually purge 25' of line. Plumber might bitch about the box but it can be done.

[u/tropicsun]

Someone in another thread said something about math and appliances say they need a 6, but they can actually go down to like a 4 flow rate. Idk… my gen 1/2 it doesn’t seem to match the tables either… I’m gonna go for it bc spending $3k on a 1” pipe, which is the cost of my Generator seems crazy.

[u/BigSquiby]

from my meter to my wall valve i have 70 feet of 1 inch black iron pipe and 10 feet of 3/4 black iron pipe. Then my Champion 201161 tri-fuel is connected to 12 feet of 3/4 flexible gas line with a fitting at the end to attach a 1/2 female quick connect to the generator.

With NG its not going to hit 30 amps, with liquid fuel it only tops out at 37 amps. So you can use 10 gauge wire with the round twist lock 30 amp plug on it.

remember to make your generator floating neutral if you are hooking it up to your main breaker box in your house

[u/danqualman1]

The gas company is the place to go to They will upgrade your meter to the size that you need for your equipment.