Enclosure for a Generator

This Instructable is all about building a box for my new generator. We couldn't really afford an inverter type generator to run the stuff we want to (airconditioner, fridges and freezers), so it a standard older type wired into the house. The box's main purpose is to help redirect/muffle the sound a little and also to help protect it from the weather. I chose to pour a concrete slab for it to sit upon and make the walls out of concrete blocks with the cores filled in with concrete to help make it denser and should reduce the noise a little.

Things I also had to consider included; placement, how well blended in it would be, airflow around the generator, weatherproofing and exhaust gases.

This unit is designed to be wired into the fuse box of the house, I hired an electrician to do this part and put the input power outlet near where I was putting the box. Its on the beam in the corner behind the box, you may see it in some pics.

The end result is as per the attached picture.

Stuff you will need:

Slab:
Cement, sand, aggregate and water
wheelbarrow or cement mixer
shovel
concrete smoothing device such as trowel and piece of wood
form-work
something to hold the form-work, stakes, pegs etc

Box part:
blocks to make walls
wood of some sort to make door and roof
ventilation type fans
hinges

Generator parts:
Generator
earthing rod (available from electrical supplies shops)
some cable to wire to the earth
handles, hinges

Safety gear:
Dust mask - cement powder can be a little nasty
Gloves - again with the cement powder, I didnt use them, but I had a hose and washed off anything that got on me
Water - needed for the concrete mix, but also good to replace fluids as you work
Tarp - shade, rain protection etc

Step 1:

A great way to start something like this is with a plan.

First up, choose a site. I had this little corner near the house that was the furthest point from both our house and the next door neighbours. It was also sheltered a little under the eave of the house. It also had no plants of note (save for an elephant ear plant that was nice and easy to cut down), and was kind of neglected. Perfect!

Next, measure up the generator. It was 800mm x 600mm. So that gives a nice easy rectangle to work with. I drew this as on paper so that Id have the measurements all the way through. After that I figured that 100mm of gap between the generator and wall sounded like enough, so added that and drew another box. Finally, after a quick trip to the place that makes concrete blocks, I picked a block type that was 90mm wide. So I added a final box around that. Sadly I seem to have thrown this piece of paper out, so imagine three drawn boxes on a piece of paper with the dimensions scribbled in. these dimensions will vary depending on the size of bricks you choose and the size of your generator.

This then gives the dimensions of the slab that will be required. Make sure that it will fit in the area you want to put it.

I went with enough bricks to make the box about a metre high. In the plan I also included a layer of half height blocks sideways at the bottom to allow for airflow intake with the plan being to have the top exhausting air to give a positive airflow path that should keep the temperature down and also vent the exhaust gases safely into the atmosphere.

*** Edit*** Found the plans! Attached as per pictures 3-6. Photos only Im afraid, but they are easy enough to read :)

Comments

[juanangel]

I bet your generator is using a lot of fuel. The two fans is a great idea but; use one of them to feed clean cool air to the generator, as heat raises it will not need much help to get out. Use a clothe drier duct to get clean air to the carburetor. You do not need to wrap it around the carburetor or make any removal of parts. On the exhaust fan use the same kind of duct tube but this time use an "s" figure to prevent some noise from escaping out the exhaust fan. (By the way i used plastic plumbing {PVC} for mine) Make sure it is placed on the top part, not hanging down or the hot air stays inside.

[tinker234]

wow that is amazing could it be made of metal

[northernmenace]

Definitely! I used brick filed with concrete to try and absorb the sound a bit. A thin later of metal may only amplify the sound. Perhaps a layer of carpet or sound absorption foam thats heat proof. Plastic or wood should work as well, though again, may need something else to help the sound blocking.

[tinker234]

oh thanks i meant on the outside to protect the engine

[northernmenace]

Oh, yep for sure!

[rocketman221]

Good idea. I will probably make one when things finally dry up.
How well does the concrete muffle the noise?

[northernmenace]

Its not too bad, I havent had a test where Ive had to sleep as yet, but it is a noticeable difference from inside the house. The plastic on top is letting a bit escape though so will have to find something else for that. I knew Id get some out the fans due to their size, but expected less. Im thinking I might whip something up with wood and see how it goes.