Hardwiring the Generac 4582

Hardwiring a portable generator is no different than installing a permanent generator, except that one has to allow a little "slack" for the generator to move and wiggle. This is one of the reasons while I'll be removing the wheels and the "foot" and resting the chassis on either 2x4's or rubber padding on said 2x4's.

The inside-the-house portion of this project has already been done, and that can be found HERE. What will be documented on this page is the "power tail" from the transfer switch to the outside, replacing the paltry 20A circuit to the old generator.

Getting Started - Wiring

The first step, is to decide where to put the generator, and how feasible it is to wire it up considering everything that's in between. Since I tore out a rusty metal shed a while back, my initial idea was to use the remaining concrete pad as the foundation of a "generator shed". I spent a fair amount of time trying to see how I'd get wiring through the back of the house and trench my way to that concrete pad. Unfortunately, either the back stoop, the patio which is laid over concrete, or the inground pool is in the way. There's a crawl space just underneath a half-bath that I probably could have bored through and gone that route, however I couldn't reach the back wall and there were three sewer pipes inside that wall. One for the toilet in that half-bath, one for the upstairs bathroom, and one that goes to the roof as a vent. All three merge in 28" wide space, leaving very little room to run 1.25" ID conduit in between. I probably could have done it, but I wasn't confidence I'd get the hole in the right place from the outside, and thus have a lot of patching to do to fix the hole and move it over.

The crawl space under the half-bath:

Another picture by sticking my cell phone into the 18"x8" opening to the same crawl space:

And a third picture looking into the crawl space opening. Yeah, that's not really going to work out that well. It's a shame too because this crawl space opening is right behind my server farm and thus I won't have high current wires on the basement ceiling. Oh well, what can you do.

All the way at the other corner of the house, also in the back, this is what I see. A box that feeds the pool pump just outside, and a copper pipe feeding an outside hose fawcet on the other wall (side of the house). The plan is to bore through the back wall and push the conduit and the L-box through that.

Yay, a hole. One amusing thing about old houses is the depth of such holes - including the outside clapboard which is 1/2" thick cedar (and heavily rotted), the hold depth was 7" and completely of solid materials: Two layers of clapboard (1/2" each), one layer of tongue and groove backing slanted to the left (1" thick), another layer of tongue and groove backing slanted to the right (1" thick), and two 2x16 joists side by side, each actually 2" and not the usual 1.5". 1/2 + 1/2 + 1 + 1 + 2 + 2 = 7".

After boring the above 2" hole, I then used my Dremel "Multi Tool" to shave out a rectangular area for the top of the L-Box to reside flush against the first layer of clapboard, which will help me weather seal the area by using the top clapboard as an "awning" in a sense:

And, the L-Box fits nearly perfect. A bit of chalk and this will be a clean install:

Here I'm feeding the romex through the joists in the furnace room, not really an exciting picture but it's at least showing some progress. I'm surprised I got any of this done today considering the number of interruptions - 37 - I counted :)

And finally, the wire is being fed outside. This is very stiff wire and going to be a pain to snake through the conduit. I used to do this for a living using tons of cable grease and either an AC powered cable puller or a gasoline powered one depending on the jobsite. This will take a while since I'll be doing this by hand. Yes, I am using UF-6/3 romex and I'm only running schedule 40 conduit outside. Inside, the romex was fed through some joists, and stapled to the bottoms of others, depending on the area. Since that part of the basement will never be finished, stapling along the bottom of the joists is acceptable.

A couple of people suggested it is illegal to run romex in conduit, and after reading the NEC code extensively, I see nothing to suggest it's illegal, as long as the romex is rated for the wet (UF designation) which this is. It is more difficult to snake through conduit than equally sized individual conductors due to the jacket, but this allows me to skip running 1.25" conduit inside the house which is essentially impossible anyway. Far too much stuff in the way.

Here is the path the underground conduit will follow. There was a row of half-dead, scraggly shrubs here and I hacked them out to make the area cleaner as well as easier to work in.

Cut up shrubs. Seems no matter what project I'm working on, I create more and more brush piles. Sigh.

Here I've dug the trench, it's 19" deep instead of the minimum NEC required 18" depth, and I will be grading the area differently and increasing the depth further by putting more topsoil around the area overall to level of it off.

Here I'm feeding the UF 6/3 cable as well as the 14/2 cable out of the house and into the start of the conduit. This was a real pain in the butt because the 6/3 is very stiff and I wanted to be extra careful not to damage the jacket. If I still owned a cable puller this job would have been very easy and done in about an hour.

And here we have the end result - a piece of conduit sticking out of the ground with two wires, one 14/2 to power the battery charger, and 6/3 to power the transfer switch when the generator is running.

Generator "Shed"

Where is this conduit going? To a generator shed that will be built and located about 30' from the house, in place of a row of really scraggly bushes. This will protect the generator from the elements so it doesn't rust together, and allow me to permanently install the electrical and thus not have 50A cords laying about deteriorating in the weather/sunlight or making them available for people to trip on. Or, dogs chewing on it.

I investigated purchasing such an enclosure however the ones I found were expensive - $900 and up - and were far to small for the Generac 4582. I wouldn't be able to close the lid and there wouldn't be enough airspace to cool the unit (at least I didn't think so). Here is a picture of a commercially available unit through Loews/Home Depot:

In addition to protecting the portable generator from the elements, this type of thing might also be able to reduce noise significantly. While the Generac 4582 I have isn't any louder than my old 4500W Coleman, that's not suggesting in any way that it's "quiet". So my genshed will probably have to incorporate some kind of sound-reducing insulation. Also, notice the electric fan that's in the enclosure and also the "exhaust outside the box" aparatus. Both are very good ideas for generator durability and I'll include those in my build.

Okay, time for my version.

I disconnected the on-ground pool discharge PVC and moved it out of the way, then started bringing back the materials. This 4x4 will be cut to length to form the support posts.

Instead of digging holes, sticking in posts, and pouring in quickcrete, Home Depot had these things which are basically metal post holders with a really long spike on the bottom. Their normal purpose is to hold upright a mailbox post. While they weren't cheap, considering the cost of renting a post hole digger (or spending hours digging through roots) and the cost of the quickcrete, these weren't unreasonable at $16 a pop.

With the four posts inserted into the spiked holders, I was able to cut them to level which is why they appear different heights in the picture - they are - because the ground isn't level.

Here is the base, assembled out of douglas fir 2x4's. I put the joists on 12" centers instead of the normal 16" to compensate for my using 2x4's instead of 2x6's or 2x8's. This only has to support about 500lbs of generator and fuel.

Here I've framed out the sides, back, and top. The top has a 15 degree pitch and I will be installing sheets of asphalt roofing material that was left over from when I re-did the widow's walk. I have about twice what I need and it's a great product, might as well use it. The box fan is sitting there because I was debating using that as an exhaust fan, however the corners are rounded and it's such a flimsy piece of Chinese-made crud I'm not sure I would want to rely on it to cool the generator. More on that later.

It's getting dark early these days (just after Thanksgiving, 2011) so I had to set up my work lights to continue. I have the roof underlayment on as well as the back. The roof underlayment is made of the same type of plywood the floor is made of, which is a tongue-and-groove water resistant plywood. It's meant to be used under "wet" floors, and I used it in the garden shed with great results. Water just pools on it rather than being absorbed. Durable!

Now with the back and the two sides screwed on, I extended the conduit up and glued on a LB fitting, and pushed that through a 2" hole I drilled into the plywood, then fed the wires though the rest of the way which is what you see here. Both are UF-rated wire as required by code just in case the conduit fills up with water - which it shouldn't if I glued the joints correctly since both ends are well above ground. But, you never know :)

Here I've installed the roof flashing. The back one goes on first, then the sides, then the front. They're nailed on and then flashing cement is applied on top of the nailheads.

I had some leftover asphalt shingles from the garden shed I built over the summer, and coincidentally I had enough to cover this shed with one left over.

To ensure the front is well protected, I bent a piece of wide flashing to cover the last eight inches of the shingles, folding it over the front to keep the water out from the front edge.

Mounting of the circuit panel. It's a Square-D unit. The 40A 250V breaker that will feed the house is on the left, and the two 15A single poles are on the right. One of them will power the fans and the flourescent light inside the shed, and the other will power an outlet I will eventually install on the outside for "general" use.

Panel, tri-switch (two fans, one light) and the duplex that's powered from the house which the battery trickle charger will be plugged into.

Flourescent light. This will make it easier to refill the generator without having to wedge a flashlight under my chin.

More wiring progress

Here are the two fans - they're not very powerful but they were cheap. If the temperature inside the generator hut climbs too rapidly during testing, I'll replace these with something much more effective. I just couldn't pass up a pair of new bathroom fans for $20 for the pair.

The result of today's efforts (11/30/2011): wiring is all done except for the main feed not being connected to the panel yet. I also have to install the ducts for the pair of fans.

Since I had a couple of boxes of clapboard left over from something else, I decided to at least attempt to make the generator shed "pretty". I'll be painting this white if the weather holds out and if not, I'll paint it in the spring.

Here are the front doors, with two slide-latches each, to keep them closed and the generator dry and not covered in yard debris. While the plywood was nice and flat when I brought it home, leaving it outside overnight allowed it to warp. Figure, right? That's why I had to install latches on the bottom - the left door bowed out far enough to allow critters in.

Here is the 1/2" ground rod. The NEC specifies the ground rod must be 8' long and 1/2" diameter for non-ferrous ground rods (such as copper, as is the case with this ground rod). I started driving this rod into the ground by hand with a hammer and a block of wood, but it was taking forever so I machined out of mild steel an adapter for one of my air chisels so instead of a chisel point it has a 5/8" diameter "cup". I put the tool on top of the rod, pull the trigger, and the rod is slowly and consistently driven into the ground. I probably should have driven it the last six inches but I wanted the ground wire and clamp to be above ground where I can inspect them regularly. I used a scrap of 6 AWG wire for the ground, as is required. It happens to be green too :)

And here are the "exhaust ports" that will be connected to the two Nutone bathroom fans once I figure out the ductwork. Unfortunately, the corrogated metal-wire-wrapped-in-foil ducts suck and I tore both of them trying to make the tight bend, so I'm going to "remodel" the back of the shed to accomodate a few pieces of stacked plywood, then line up things inside, and use hard PVC to make the connection. More than likely I'm going to have to use a lot of silicone.

PVC Plumbing for the two bathroom fans. To my amazement this fit tight enough that applying silicone to the joints made a tight enough seal.

And, with the covers.

The start of the exhaust extension. I'm going to use ERW conduit because I have a ton of it but will monitor it closely during the several-hour test I plan to do so I can determine if my theory of the exhaust not being hot enough to remove the coating is correct.

With the wheels and "leg" removed, the generator now fits easily inside the generator shelter. I will be fabricating a pair of brackets that will attach to where the wheels used to be and to the floor to ensure it doesn't "walk" during use.

I needed a slight bend at one end to fit on the generator's existing tailpipe, and my bender isn't capable of cleanly bending 1-1/4" tubing so I just hacked up a 90 degree bend and welded it on. And yes, I didn't inhale the highly toxic zinc fumes.

Here is the exhaust pipe going through a box plate with a hole sized just a hair too large, which will allow the exhaust pipe to move around as it gets hot and not bind and possibly break something.

Here is the exhaust pipe sticking out of the shelter, ready to be cut to the appropriate size.

You can see the exhaust in the background, and also that I've attached the ground rod/wire to the generator's ground terminal.

And here's the cut tailpipe with the spark arrester and spark arrester keeper installed over the conduit. Perfect fit, though I have to drill and tap a small hole in the conduit so these parts stay put. During the quick test I did, they both shot off and I had to find them in the yard 20' away. That explains why they were screwed to the original tailpipe :)

The next step is to connect the generator to the panel. I used two 50A L14-50 plugs and a dryer outlet on the wall. Technically, one should reverse the connection on the wall where the socket is on the cord and the plug is on the wall, however Home Depot and Lowes didn't have these parts in stock, nor could they order them apparently. Mostly because I couldn't find someone I could explain what an L14-50 generator port is. For safety reasons I'm going to weld onto the dryer outlet box cover two tabs for wire ties, so that side cannot be unplugged thus the high current will not come in contact with anything, including people and pets. I will reverse it once I find the parts. Here are the two connectors where they will eventually go, so I could measure the necessary wire to go between. I'll be using 6 AWG THWN of course, and put it in a protective sleeve of some kind.

One of the L14-50's wired and ready to be closed.

And here's the other one, and the reason why I snapped a second picture is because it shows the waterproof flexible conduit I used as a cord sheath.

12/13/2011 - I fired up the generator and once the choke was no longer necessary (less than a minute) I closed the doors to the generator hut and let the generator run for 30 minutes, powering only the flourescent light inside and the two NuTone bathroom fans. Here's a picture of the doors being blown open by the fans, showing me that they're working.

Unfortunately, the two fans weren't even close to being sized right to evacuate all the ambient heat the generator produces, so I will have to remove them, close the hose, and install something larger. Significantly larger. I'll be using this fan, which is a roof fan capable of 1200 cfm according to the box. Fun, I get to do the roof over!

"X" marks the spot. Wait, no, this is a "O". Either way, that's what I have to cut out for the new roof fan.

This was very painful to cut, psychologically. A big hole in a new roof where I put a lot of effort to get right. I put a piece of plywood across the top of the generator to ensure nothing dropped onto it, just in case later on dust and dirt gets sucked in.

Here I have the fan "shoved" under the shingles so at least it it rains water won't get inside the generator hut, but I need to move it up more and to do that I'll have to work either a hacksaw blade or a sawzall blade under the shingles to cut a few nails. Hopefullly I won't have to redo the entire roof and maybe I'll get lucky and a little roofing cement might do the trick. If not, I can redo the roof. I have another pack of shingles laying around.