Setting up an MEP-003A as a permanent stand-by Generator

Mr4btTahoe

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Hey alls,

Now that I've got the unit somewhat buttoned up and load tested, it's time to put it in place and prepare it for use. In this thread, I'll detail how I'm doing just that... a lot of which I've never done.

Anyways... lets get started. First, I needed a solid location for the unit to sit. I have a firewood storage "building" (without walls) roughly 100' from our house. I decided to place the unit on the far end of this structure and to extend the roof over the unit. This will be two-fold. The roof and structure will protect the unit from the elements while the mass of firewood will be nice sound barrier between the house and the unit.

So.. we started by pouring a pad. Pad is roughly 5" poured by hand.. mixing in buckets. It went fairly smoothly. We also integrated some "footers" into the pad just to add a bit of strength. Formed it up with treated 2x6s and gave it a shot. This is the first time I've poured concrete. We were short on mix so we couldn't fill the form. Kinda sucks.. but we managed to get it fairly level and it doesn't seem to hold water now. It isn't perfect... but it'll serve it's purpose for sure.
 

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Mr4btTahoe

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Next was to move the unit from the garage where its been to get repaired.. to the back and onto the pad without a tractor. We got creative. With a couple of 4x4 posts... a 4" piece of C Channel... some 2" straps and 2 come-a-longs.. we turned the truck into a crane of sorts. Not ideal.. but worked great. Now it's wrapped up until the weekend where I'll get the roof extended and start laying in electrical.

I'll be doing the electrical install as per our current NEC schedule (we're still on 2012). The system will be installed as a non-separately derived system. We'll be dropping 2-2-2-4 alu. urd. in conduit. The unit will have a ground rod at the pad but will be bonded to the main service grounding system. We will also verify that the neutral and ground are un-bonded at the generator as our method of transfer will only switch the power conductors.. not the neutral or ground. Stay tuned.
 

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Scoobyshep

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Looks good, Make sure you use NOALOX on the connections. If it were me I wouldn't drive a rod at the generator because now you are adding a ground point to the ground network using a smaller ground conductor (code calls for 4 copper), That being said it also depends on your local codes.

Looks great though.
 

Mr4btTahoe

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Looks good, Make sure you use NOALOX on the connections. If it were me I wouldn't drive a rod at the generator because now you are adding a ground point to the ground network using a smaller ground conductor (code calls for 4 copper), That being said it also depends on your local codes.

Looks great though.
I liked the idea of adding a rod for lightning protection more than anything... but not necessary. May not do it then. If you dont mind, what code calls out #4 copper as minimum? I'd like to read up on it. 250.66 says #6 is fine for anything under 1/0 aluminum. Perhaps I'm taking it wrong.
 
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Scoobyshep

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I liked the idea of adding a rod for lightning protection more than anything... but not necessary. May not do it then. If you dont mind, what code calls out #4 copper as minimum? I'd like to read up on it. 250.66 says #6 is fine for anything under 1/0 aluminum. Perhaps I'm taking it wrong.
I am not in the office, so I cant look it up. 250.66 is for the service, and the last time I ran into this situation we had to match the service size because when you are running on utility the ground is still in play and would need to be able to take the full force of the possible fault current applied to it.
 

Mr4btTahoe

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I am not in the office, so I cant look it up. 250.66 is for the service, and the last time I ran into this situation we had to match the service size because when you are running on utility the ground is still in play and would need to be able to take the full force of the possible fault current applied to it.
If you get time, check please. The wording on 250.66 has changed multiple times. Last change Id seen had changed the wording to say that no LARGER than #4 aluminum or #6 copper was required unless going to an encased rod, etc.. or an engineer specifies larger.
 

Chainbreaker

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I've gone back-and-forth on whether a driven ground rod is necessary for generator's chassis ground when hooked up to house service panel. Here is my thinking...

1. If you ever plan to unhook genset from house service panel and run generator off any kind of load bank (garage type heater or what have you) you will need a driven gnd rod and will need to re-bond neutral to frame gnd. In other words, when running as a Self Derived System (SDS mode).

2. If by chance your gnd conductor in the cabling to house service panel were to ever be disrupted (intermittent gnd terminal continuity, cut or disconnected gnd wire) then you are left with no gnd to your genset chassis. I would not want to grab onto my generator and somehow inadvertently become the ground path if my unit experienced an electrical fault at generator with no actual grounding on a rainy night during a storm due to a bad gnd connection to house.

Here is how I set up my genset to handle both scenarios (house gnd & SDS field gnd) while always maintaining a chassis gnd for genset & trailer. See last picture in Post #1. Note: I have the genset's driven gnd rod placed about 30' from service entrance gnd, to prevent any gnd loop potential.
 

islandguydon

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Good looking, unit.

I don't know if you had a thread about the rebuild/recondition to this point of install, I just came back into the fold. My passion is atlernative fuels for the MV, and power generation. I have poured many a pad in my day for stand by generators so in my "humble opinion" I wanted to chirp in on your thread. I hope you don't mind.

I assume your going to trench 8 x 4 romex 12"-18" down in the ground for the 100' run to the structure your going to power up therefor, I did not notice any PVC conduit capped off in the concrete form to run the power to your transfer switch on the structure, and a ground rod sticking up. Remember, ground, ground, ground..!!!

I would also use 4 1/2" x 4" concrete lags on 4 points to secure the MEP to the concrete. Any hardware store will have them in the fastener section. All you need is a 1/2" masonry bit and a 1/2" box wrench and a hammer to beat the lags into your Pre drilled holes.

Funny fact, Once, I forgot to secure the unit and it vibrated off the pad, the conduit kept the unit from completely vibrating off the pad.




What is the plan for power delivery to the structure......?
 
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Mr4btTahoe

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Good looking, unit.

I don't know if you had a thread about the rebuild/recondition to this point of install, I just came back into the fold. My passion is atlernative fuels for the MV, and power generation. I have poured many a pad in my day for stand by generators so in my "humble opinion" I wanted to chirp in on your thread. I hope you don't mind.

I assume your going to trench 8 x 4 romex 12"-18" down in the ground for the 100' run to the structure your going to power up therefor, I did not notice any PVC conduit capped off in the concrete form to run the power to your transfer switch on the structure, and a ground rod sticking up. Remember, ground, ground, ground..!!!

I would also use 4 1/2" x 4" concrete lags on 4 points to secure the MEP to the concrete. Any hardware store will have them in the fastener section. All you need is a 1/2" masonry bit and a 1/2" box wrench and a hammer to beat the lags into your Pre drilled holes.

Funny fact, Once, I forgot to secure the unit and it vibrated off the pad, the conduit kept the unit from completely vibrating off the pad.




What is the plan for power delivery to the structure......?
Thats in the last part of post 3. We're dropping 2-2-2-4 in conduit. I'm not 100% on how I'm going to anchor the unit to the pad yet. I don't have a good way to move it so drilling the pad for the holes that are in the frame. I may utilize the tie down rings. We'll see. I'm also considering isolating the unit from the concrete using some treated 2x under the runners just to reduce vibration and such. I'm also not 100% on hard wiring the unit. That's why I didn't run the conduit through the pad. I'm considering running the service entrance large twist lock outlet depending on cost. Haven't priced components yet.

I'll be digging the trench this weekend and dropping the main line in.
 

Mr4btTahoe

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I've gone back-and-forth on whether a driven ground rod is necessary for generator's chassis ground when hooked up to house service panel. Here is my thinking...

1. If you ever plan to unhook genset from house service panel and run generator off any kind of load bank (garage type heater or what have you) you will need a driven gnd rod and will need to re-bond neutral to frame gnd. In other words, when running as a Self Derived System (SDS mode).

2. If by chance your gnd conductor in the cabling to house service panel were to ever be disrupted (intermittent gnd terminal continuity, cut or disconnected gnd wire) then you are left with no gnd to your genset chassis. I would not want to grab onto my generator and somehow inadvertently become the ground path if my unit experienced an electrical fault at generator with no actual grounding on a rainy night during a storm due to a bad gnd connection to house.

Here is how I set up my genset to handle both scenarios (house gnd & SDS field gnd) while always maintaining a chassis gnd for genset & trailer. See last picture in Post #1. Note: I have the genset's driven gnd rod placed about 30' from service entrance gnd, to prevent any gnd loop potential.

Pretty slick setup.

I'm not overly worried about disconnecting the unit as I'm going to integrate the "load bank" into the load center at the house. In the near future, I'll be building a solar water pre-heater for the house water supply. I'll be using a large heavily insulated tank as the heat exchanger and am going to integrate a few submersible 240v heaters in that tank. That way, when exercising the unit on a monthly basis, I can apply a decent load to the unit and not just waste the energy.. but add heat to our heat exchanger tank.

I do like your switched neutral bond. Pretty slick setup which I may look into anyways as a "just in case" measure.
 

Scoobyshep

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Thats in the last part of post 3. We're dropping 2-2-2-4 in conduit. I'm not 100% on how I'm going to anchor the unit to the pad yet. I don't have a good way to move it so drilling the pad for the holes that are in the frame. I may utilize the tie down rings. We'll see. I'm also considering isolating the unit from the concrete using some treated 2x under the runners just to reduce vibration and such. I'm also not 100% on hard wiring the unit. That's why I didn't run the conduit through the pad. I'm considering running the service entrance large twist lock outlet depending on cost. Haven't priced components yet.

I'll be digging the trench this weekend and dropping the main line in.
can always drill the anchors in at a slight angle.

Be aware if you install a twistlock (or any other cord and plug disconnect) you will loose your grounding when disconnected.
 

Mr4btTahoe

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can always drill the anchors in at a slight angle.

Be aware if you install a twistlock (or any other cord and plug disconnect) you will loose your grounding when disconnected.
If I went that route, I would likely have a rod at the pad where the unit stays connected all the time.. and the twist lock would bond the rod and gen frame to the house grounding system when connected. That way, the unit always has a ground path no matter how it is being used.
 

Scoobyshep

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Florida
I've gone back-and-forth on whether a driven ground rod is necessary for generator's chassis ground when hooked up to house service panel. Here is my thinking...

1. If you ever plan to unhook genset from house service panel and run generator off any kind of load bank (garage type heater or what have you) you will need a driven gnd rod and will need to re-bond neutral to frame gnd. In other words, when running as a Self Derived System (SDS mode).

2. If by chance your gnd conductor in the cabling to house service panel were to ever be disrupted (intermittent gnd terminal continuity, cut or disconnected gnd wire) then you are left with no gnd to your genset chassis. I would not want to grab onto my generator and somehow inadvertently become the ground path if my unit experienced an electrical fault at generator with no actual grounding on a rainy night during a storm due to a bad gnd connection to house.

Here is how I set up my genset to handle both scenarios (house gnd & SDS field gnd) while always maintaining a chassis gnd for genset & trailer. See last picture in Post #1. Note: I have the genset's driven gnd rod placed about 30' from service entrance gnd, to prevent any gnd loop potential.

If youll never unhook the generator then a rod isn't necessary

If there is any chance the generator will be run while completely disconnected then a rod is needed.

Keep in mind the generator is only a Separately Derived System IF there is no switching action at the neutral (its rare to see one wired as a switched neutral but they exist). Truth be told if you are loadbanking and you arent using alot of 120 volt the neutral to ground bond isnt critical. The neutral to ground bond is only to establish neutral at 0 volt. the loadbanks should be well balanced to the point where it would keep the output balanced as well.
 

Mr4btTahoe

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If youll never unhook the generator then a rod isn't necessary

If there is any chance the generator will be run while completely disconnected then a rod is needed.

Keep in mind the generator is only a Separately Derived System IF there is no switching action at the neutral (its rare to see one wired as a switched neutral but they exist). Truth be told if you are loadbanking and you arent using alot of 120 volt the neutral to ground bond isnt critical. The neutral to ground bond is only to establish neutral at 0 volt. the loadbanks should be well balanced to the point where it would keep the output balanced as well.
Well after pricing quality water-tight 60a connectors, it'll be getting hard wired. Lol

Now I'm looking for ideas on running conduit to the terminal box on the unit. I don't want 2-2-2-4 coming out of conduit and just loosely being stuck into the box. I'm leaning towards drilling to box and running conduit to the box for a secure/clean setup.

I'm having trouble finding pictures of these units setup as permanent installations.
 

Scoobyshep

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Well after pricing quality water-tight 60a connectors, it'll be getting hard wired. Lol

Now I'm looking for ideas on running conduit to the terminal box on the unit. I don't want 2-2-2-4 coming out of conduit and just loosely being stuck into the box. I'm leaning towards drilling to box and running conduit to the box for a secure/clean setup.

I'm having trouble finding pictures of these units setup as permanent installations.

Thinking aloud here (so to speak) you could drill into the front or top of the connection box and pipe into it with a piece of sealtite or carflex.
 

Zed254

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I'm having trouble finding pictures of these units setup as permanent installations.
Good install thread on a permanent MEP-803A installation for home backup here:
 

islandguydon

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Remember, The gen head & unit is grounded to the frame, hence if the pad is grounded by a 8' rod, & its steel FRAME is lagged to the concrete, your covered all the way around, IMHO.

Btw, there should always be a bond from the unit to the rod, I always just secure it in the pad, ground,ground, ground.

IGD
 
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