Burying a generator vault into a bank

[Sodo]

Winter is coming and the forum is slowing down so here's a project for ya!.
This was done over the last 2 weeks and is not finished yet.

The Cedar log.

Cedar boards 1 1/2" x 13". Appx 160 board-feet. At $5to 10 bucks per bf that stack of Cedar could be worth $800-1600.

Solid cedar generator vault. This whole structure was cut from that one Cedar log in the first photo.

The hole in the bank.

Wrapped the cedar with black plastic. Setting the vault into the bank.

Wiggling the tractor out from between the containers.

Generator vault covered over with dirt.

Trimmed and ready for the doors.

Gonna have questions about grounding. I'm using the generator in a 3-wire configuration. So do I just ground the frame of the generator to a ground rod? It's about 60 feet of 10-2 wire to the one outlet in the building. There is no "panel", it's basically just a 60 foot extension cord to an outlet screwed to a post. It runs four 0.35A LED shop lights off one leg. So 1.4 amps off one leg for lighting.

I dont yet have a plan how to plumb the exhaust and air inlet thru the door. The exhaust seems easy. I'm thinking I will use 6 " or 8" heating duct to plumb the cool air inlet to the generator fan.

 

[RickB]

Don't forget to engineer a way for that cooling air to get back out.

I don't understand the purpose of all that effort, but then I don't have to.
It will be quiet and out of sight I guess, so long as you don't fry it.

 

[coldsteelva]

If your only running LEDs, perhaps a suggestion. Can you install a battery with an inverter? To simply run low draw LEDs, it seems it might be more effective to use the generator and a battery charger to recharge a deep-cycle battery periodically and then the rest of the time you can use your LEDs powered off the battery with silence.

 

[Sodo]

Buried it for the quiet. I use it for power tools and welding. When NOT needing lots of power I use batteries & 12v LEDs, sometimes a little Honda EU2000i. But this generator in the vault is much quieter than the little Honda (if nearby). I like the silent aspect of battery power - just under the excavator boom you can see a solar panel on the tree.

I can put the little Honda in the vault too and run with just one leg (in circles). :laughing: :laughing:

 

[amigauser]

I would also be worried about keeping the generator cool. If that is air cooled they need a lot of airflow to keep from cooking.

 

[Sodo]

Hmmmm maybe need a 120v fan running all the time the gens running to ensure ventilation.

 

[CCWKen]

Yep. You should have put some type of cross ventilation to get good air in and bad air out. Otherwise; the engine will run rich and compound the heat problem. You might want to run the engine exhaust to the outside of your "cave" as well as add some forced air ventilation in the door.

 

[ultrarunner]

A duct to draw in air directed to the fan?

My uncle built a bunker of concrete set into a hillside where only the door was visible... he did have and intake duct and venting duct... little 1960 Winco 2500W gas generator that was military surplus.

It was quiet and always cool being in the hillside.

 

[MossRoad]

If I were using it in that shed, I'd just wheel it around so that the exhaust is pointed directly toward the very open door and run it as is. You have lots of ventilation in the height of the doorway.

Beautiful log, by the way. :thumbsup:

 

[Sodo]

Yes Cedar is beautiful. I sort of "rescued it" out in the woods. I found it bulldozed into a pile of brush, as waste. It had no rot. It felt good to cut it into beautiful boards.

The entire purpose is to reduce the noise of 16HP. Pretty sure venting / cooling ducts / exhaust thru the door is not rocket surgery but I'd like to see how others have done it. Retaining the 'quiet' with holes in the door probably IS rocket surgery.

Wish I knew how the grounding should be done.

 

[MossRoad]

Yes Cedar is beautiful. I sort of "rescued it" out in the woods. I found it bulldozed into a pile of brush, as waste. It had no rot. It felt good to cut it into beautiful boards.

The entire purpose is to reduce the noise of 16HP. Pretty sure venting / cooling ducts / exhaust thru the door is not rocket surgery but I'd like to see how others have done it. Retaining the 'quiet' with holes in the door probably IS rocket surgery.

Wish I knew how the grounding should be done.

What's the manual say about grounding? Nothing. It says the ground is connected to the AC outlet ground and has to be connected to any building properly by an electrician. It says nothing about grounding the generator itself, does it?

 

[MossRoad]

This should help you regarding grounding of a portable generator when not connected to a building....

https://www.osha.gov/OshDoc/data_Hurricane_Facts/grounding_port_generator.pdf

In a nutshell, the generators frame is the ground when you are powering tools directly from it and no ground rod is required.

 

[CurlyDave]

You might need a lot more ventilation than you are being told. I put a ~12000 watt Generac in a shed I built.

The exhaust is piped out through a muffler from a Ford 9N, the fuel is propane from our tank, and I provided ventilation. both a 9" x 16" vent, an open window, ~ 10" x 30" and a HF ventilator fan (Search results for: 'ventilator', blowing out. The HF ventilator is reduced to a 6" diameter duct through the wall with a 8" to 6" cone.

While the generator runs, the temperature inside the shed climbs steadily to over 100 degrees F with the man door closed, even if I set up a box fan blowing in just inside the vent.

If I leave the man door open, the temperature stays reasonable inside the shed, and that is how I run it now.

The problem, of course, is that with the man door open the noise is impressive.

Fortunately I was able to locate this 100' from the corner of the house, more like 150' from our bedroom, so the noise is tolerable, but definitely not quiet.

The way to handle the fans is simply to plug them into one of the outlets on the generator, so that generation running = fans on.

 

[Sawyer Rob]

As long as that door is open, it looks to me like the heat will rise and go out, drawing in cool from down low (where the genset is) to replace it.

I wouldn't worry about it...

SR

 

[PAGUY]

At a friends cabin they built a wood shed and designated a side for the generator to run with the door shut. It has a cement floor with a large eyelet buried in cement to chain it for security. They placed it in such away that the exhaust pointed toward a vent to the outside.They shut the door while it was running so less noise would be heard from inside the cabin. What happened was the vent was made of plastic and screening and melted from the heat of the exhaust. The building was made primarily of metal siding and possibly saved a fire from occurring. They have since installed piping to vent it up and through the roof of the shed. No problems since this improvement. The vent now allows outside air into the shed for the generator to run with ample air.

 

[Sodo]

This should help you regarding grounding of a portable generator when not connected to a building....
https://www.osha.gov/OshDoc/data_Hurricane_Facts/grounding_port_generator.pdf
In a nutshell, the generators frame is the ground when you are powering tools directly from it and no ground rod is required.

The reason for my grounding concern is I use it with 60 feet of "extension cord" (for now). But I will bury a wire and plumb it to the shop, at which point it's similar to "60 feet of extension cord" except 10-2 Romex. I thought I understood that grounding became important to shorten the length of the groundpath? If grounding rods at the building won't help anything, I'd like to know that as I have rocks just a couple feet down.

Utility-safety-alert: The nearest grid is 2 miles away, lets not get too far off-topic into danger to utility workers.:laughing: It will NEVER be hooked to the grid and never a danger to utility workers.

 

[Sodo]

They shut the door while it was running so less noise would be heard from inside the cabin. What happened was the vent was made of plastic and screening and melted from the heat of the exhaust. The building was made primarily of metal siding and possibly saved a fire from occurring. They have since installed piping to vent it up and through the roof of the shed. No problems since this improvement. The vent now allows outside air into the shed for the generator to run with ample air.

For the venting I think I can figure it out (not plastic !! ) . I've seen a friend's setup (much bigger 'room' though) and not as 'thought out' as I will do it.... and it worked (6500W). He did not have an exhaust, the exhaust simply mixed with all the air in the room, and just a "grating" on the door. Which the sound passed thru readily.

A thermometer will tell me if more ventilation is needed, its a balance of noise vs temperature I suppose. I like a challenge. Easy to add fans running off the 110v as Dave said. I'm becoming 'hard of hearing' and not just selectively. Background noise makes it hard for me to understand folks talking so I like to eliminate unnecessary background noise. Also like to listen for trucks etc driving past on "my" road & prefer not to announce (to them) that there's a shop in the woods. Also listen for someone coming up the driveway. And hear myself think. And listen for wildlife. Quiet is good, power is good. Cedar is good. Life is good. All good!

 

[ultrarunner]

Did the KX41 make short work of the excavation?

Only been around two bunker generator installs... both had a duct to supply outside air within inches of the genset air intake.

 

[MossRoad]

The reason for my grounding concern is I use it with 60 feet of "extension cord" (for now). But I will bury a wire and plumb it to the shop, at which point it's similar to "60 feet of extension cord" except 10-2 Romex. I thought I understood that grounding became important to shorten the length of the groundpath? If grounding rods at the building won't help anything, I'd like to know that as I have rocks just a couple feet down.

Utility-safety-alert: The nearest grid is 2 miles away, lets not get too far off-topic into danger to utility workers.:laughing: It will NEVER be hooked to the grid and never a danger to utility workers.

Extension cords are fine for each individual tool. But once you hook it to an outlet box fastened to the building, I'll guess it will no longer meet code, even if you aren't hooked to the grid.

 

[Industrial Toys]

I replaced the gen end on a 10K or so Northern/Yanmar genset. It had been in a special built dog house of sorts and a poorly built exhaust arrangement allowed exhaust into the compartment. High ambient temperatures fried the armature.