Greenhouse Generator Hook-up

Hello! I hope you’re well. Severe storms have been sweeping through our area this winter, so I thought I’d take a moment and share with you what our generator-to-greenhouse hookup looks like.

Here’s a little detail we learned the way. Our greenhouse has a 4-prong 20amp plug. But our generator has a 4-prong 30amp outlet. They look very similar, but a 20amp plug and a 30amp outlet are not compatible in a “plug and play” kind of way.

We purchased a 10-guage, 30amp generator extension cord from from Harbor Freight. It plugs into the 4-prong 30amp outlet on the generator, but cannot match the plug in our greenhouse.

I went to an electrical supply company to look for a solution and the clerk at the desk collected the parts that we’d need to make a custom adaptor cord to connect the extension cord to the greenhouse.

Upon seeing my bewildered look and learning that I have zero electrical skills, he began opening the packages and assembling the cord at checkout for me. (Something he said he wasn’t really allowed to do.) I watched and tried to soak in everything he was showing me. There’s a little bit of me that is really curious about electrical wiring now— but only a little. Maybe some day I’ll find an opportunity to learn more.

Inside the greenhouse we have a power cut off and transfer switch. In order to change the power supply from the power company’s box on our property to the greenhouse I:

1. Plug the greenhouse into the generator.

2. Turn the generator on.

3. Pull the handle down on the double throw safety switch to the off position to cut off power from the grid.

4. Pull the handle further down to connect to the generator.