Standby Generator and Natural Gas Connection

I have a house with a 22KW standby NG generator. The generator was supplied with the appliance connector recommended by the manufacturer (Generac) (as opposed to a field created CSST connection). My question is, under model codes, does this connector need to be protected via a vented sleeve for the full length (as CSST would); does it need to be fastened / anchored; and what is the maximum length of unsupported tubing allowed? I already see a problem in the installer did not allow proper maintenance clearance, therefore some modification will need to be accomplished. I want to alert the electrician and plumber to any other modifications they will need to make.

Where are the Generac installation manuals? All those items should be specified. If you don’t have the manuals look them up online.

No need to assume it should be CSST. After all the generator is a gas appliance and follows the same rules as every other gas appliance in the home. It’s been my experience the gas distribution system is not properly sized for the home when a generator is added after the home is built. This would be the focus of my inspection however you may want to refer this to a licensed plumbing contractor who is qualified to size the fuel gas system.

Since you mentioned codes why not check your local fuel gas code?


I did contact the state plumbing inspector and to my surprise, found in KY the plumbing department does not address fuel gas piping. They leave that to the local authority having jurisdiction. And, God bless them, those folks are not always as well trained as the public would suspect.

RE: Manuals. The units were shipped with the correct flexible connections. The manuals do not stipulate the fuel gas code requirements, apparently because that may vary from locality to locality. Unfortunately the electrical contractor who had ‘installed’ the units pulled the flex connectors out, and those, as well as the keys to the generator access panel were lost. The proper connectors were eventually found after a great deal of effort on the part of the general contractor’s rep. As an aside the original connection by the plumber used an indoor rated connector of 5/8" diameter, 3’ long. It was rated at 1/3 the capacity the generator required, and the unit would not even start. From this I have reinforced my opinion many mechanics are not as well versed in their trade as would be supposed.

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It’s all about the volume of natural gas going to the generator. A 16KW generator can use over 300,000 BTU per hour. Often this will require a high-pressure gas meter.

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When I had my Generac nat. gas whole house generator installed, they Tapped off the gas meter and attached the CSST to the wall and buried it 48 feet and around a corner and attached it to the house again and connected it to the generator…maybe ~24" away.

Mine was a 16KW generator and no high-pressure gas meter was required but, as I recall, the CSST was 1 1/2" or 2" and it was hair low pressure-wise on the generator so they just turned it up a little at the generator and it works great.

They changed my 200 amp interior service disconnect to a remote distribution cabinet and made the exterior automatic transfer switch the service disconnect.