2011 Mep 803 wiring for house

[fpchief]

According to the TM, it looks like Terminal L2 is not used unless it is 3ph power. The pics are what i have and i need to move the lead from L2 to L3 and the rest is good to go. Please take a look and tell me what you think. I just got it off trailer and set up today. The last pic is my use of mechanical advantage getting that heavy girl off the trailer by myself. The breaker box pic just shows the cutout for generator power only and also the plug installed that drops down below the box.

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[AfghanVeteran2010]

Yes L1 L3 is what you want to use in 120/240 configuration. Might want to put a grounding rod on it if you haven't. Very nice setup

 

[fpchief]

Yep, the rod is going down after supper. Thank you for your help!!

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[jimbo913]

If it is connected to the house panel and grounded there, you do not need or want a second ground by driving a ground rod.
The ground rod is for stand alone power generation where the unit is not connected to another ground.

 

[fpchief]

I did not know that nor ever heard of that. So the ground it is getting via the plug mounted on my house is sufficient grounding? I did not get to ground mine anyway. I expended myself taking generator off the trailer.

 

[jimbo913]

It is my understanding that if the ground path is uninterrupted, as with most interlock setups, then it is properly grounded for powering the house.

And, if you wanted to power something remotely that is not on the house circuit then it needs to be wired differently, have the ground rod driven and the bus bar in place.

Looks to me like you need to remove the bus bar at the bottom of the gen panel.

I am no licensed electrician but went through this during my install and have been running successfully for some time. I am sure the electrical guys will happen along and explain much better than I can.

 

[Daybreak]

Howdy,
MEP-803A 10 KW connection to house.
Your wire size looks a little small.
use proper rated wire. 6/4, with all 4 wires connected. ( 2 hots, 1 neutral, 1 ground) Actually if you are permanently installing it, you would be better off running conduit and using 6awg THHN wire. 6/4 SOOW is rated at 45 amps, the higher amperage rated wire would be 6/4 W-type cord, rated 87 amps.




The MEP-803A 10kw does 52 amps at 120/240

* all 4 wires connected and bonding strap removed.

 

[Guyfang]

If it is connected to the house panel and grounded there, you do not need or want a second ground by driving a ground rod.
The ground rod is for stand alone power generation where the unit is not connected to another ground.

So what happens when you have a damaged cable. Say the ground wire is cut? Or for some reason the ground wire is removed? The gen set is no longer grounded, that's what. And yes, having seen something like that, it can happen. I would say the probability is small, but not out of the question totally.

 

[fpchief]

Howdy,
MEP-803A 10 KW connection to house.
Your wire size looks a little small.
use proper rated wire. 6/4, with all 4 wires connected. ( 2 hots, 1 neutral, 1 ground) Actually if you are permanently installing it, you would be better off running conduit and using 6awg THHN wire. 6/4 SOOW is rated at 45 amps, the higher amperage rated wire would be 6/4 W-type cord, rated 87 amps.

View attachment 688211


The MEP-803A 10kw does 52 amps at 120/240

* all 4 wires connected and bonding strap removed.

My cable is 10 AWG 300v. So step it up to be safe? It is what i had when i had a different portable generator being used to run the house but i can understand using larger wirew due to possibly running more loads at a time now.

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[csheath]

I am not a licensed electrician but here is my opinion:

Looks like you already have the panel interlock so you are good there. You need to upgrade your panel breaker, generator receptacle, and house generator wiring to 50 amp which is quality 6 gauge. I would install a 50 amp RV box on the side of the generator then get a good 50 amp generator cord. Having a 50 amp plug on the generator makes it easier to connect an external load device for testing. If you have space to store one a used electric range will make a decent load device. A 50 amp range cord will plug right into a 50 amp RV receptacle.

It is my understanding that you need to disconnect the ground bonding strap on the generator when properly connected to the house. When testing with an external load bank I was told to reconnect the bonding strap so I just loosen mine at the lower connection and swing it up some for house use. I would put a grounding rod on the generator.

I think you will get a lot of vibration putting this on a rigid pad like concrete. If I were you I would either get a rubber stall mat from tractor supply and put under it or just take the blocks out from under it. I put mine right on the ground and I don't sense any vibration. The aluminum skids should hold up fine in the dirt.

 

[DieselAddict]

My cable is 10 AWG 300v. So step it up to be safe? It is what i had when i had a different portable generator being used to run the house but i can understand using larger wirew due to possibly running more loads at a time now.

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10 gauge is too small. You will trip your 30a panel breaker if you try to take advantage of the 10kw rating of the generator. You need to run all new stuff from the breaker panel out to the generator. A new 50a breaker, 6 gauge wire, and 50a plugs are the minimum. As mentioned before run a conduit out to the generator and use THWN wire. It is better suited for the heat rise of your application.

A ground rod at the generator is a fine idea. Be sure to remove the bonding jumper (bottom right of your terminal image). That is a code requirement for your application.

 

[Csm Davis]

You only want one ground in any situation, be it standalone with a rod driven nearby or your house which already has a rod driven nearby. I don't remember the exact reason but it is explained in one of the many how to hook my generator to my house threads and code also says only one. I trust most of what I find on here but you really should at least have a certified electrician stop by and check your work before you power it up the first time. I bought my buddy a beer and a burger and he helped me actually build my cable hookup.

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[DieselAddict]

You only want one ground in any situation, be it standalone with a rod driven nearby or your house which already has a rod driven nearby. I don't remember the exact reason but it is explained in one of the many how to hook my generator to my house threads and code also says only one. I trust most of what I find on here but you really should at least have a certified electrician stop by and check your work before you power it up the first time. I bought my buddy a beer and a burger and he helped me actually build my cable hookup.

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Its easy and common to confuse ground and bonding. Its normal and desirable to have multiple grounding points in a system (so long as they are all connected together and at the same reference potential). In the case of a backup generator it is not unusual to have a ground rod at the generator. You'll want to connect the generator with a 4 wire setup so you can connect the ground at the generator with the ground for the connected electrical system. With my setup at home I have a ground rod driven where I park my trailer mounted generator. I have a ground strap connected and stored on the trailer just for that purpose. Before going into service with the backup I'll connect the ground strap to the ground rod, slip off the bonding jumper on the terminal board, then I'm good to go.

Depending on your soil conditions you may be required to have multiple ground rods in your system. If you put in a lightning arresting system you are guaranteed to have multiple ground rods and likely even a ring of ground rods with nice heavy wire between them.

The part that this is confused by is the bonding location. You can only have one bonding location in a system. The bonding location is where the neutral and ground are connected. This is why we remove the bonding jumper at the generator if its being connected to a system that already has a ground-neutral bonding point.

In summary - multiple ground points connected into a common circuit is good. Multiple ground to neutral bonding locations is bad.

To totally cover your bases its always good to refer to a local inspector and/or electrician to see if there are any special rules for your area. The setup shown by the OP will certainly fail an inspection. I recommend installing it to code.

 

[csheath]

You only want one ground in any situation, be it standalone with a rod driven nearby or your house which already has a rod driven nearby. I don't remember the exact reason but it is explained in one of the many how to hook my generator to my house threads and code also says only one. I trust most of what I find on here but you really should at least have a certified electrician stop by and check your work before you power it up the first time. I bought my buddy a beer and a burger and he helped me actually build my cable hookup.

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I think that is where disconnecting the bonding strap comes in. You don't want the neutral and ground bonded in two locations. As far as I have read having another ground rod on the generator is okay as long as the bonding strap is disconnected and would be required when testing the unit while it is not connected to the house.

I don't see an advantage to hard wiring a unit through conduit and it makes load bank testing more time intensive to get it disconnected. Installing a good 50 amp receptacle on the generator and using a 50 amp generator power cord is the best way to go IMO.

 

[DieselAddict]

I don't see an advantage to hard wiring a unit through conduit and it makes load bank testing more time intensive to get it disconnected. Installing a good 50 amp receptacle on the generator and using a 50 amp generator power cord is the best way to go IMO.

That is acceptable but to get to a true 50a cord is going to push you to 4 gauge. 6 gauge cord isn't rated for 50a due to the limited heat rise allowed in those cables. If you could find a 90c rated cord then you would be good. I've not seen anything like that available in the normal commercial channels.

Having a short piece of #6 cord with the rest of it being THWN is the best combination to get you what you want in reliability and convenience.

In the spirit of full disclosure I'm running 100' of 6 gauge SOOW cord between the generator and the house with a 50a inlet plug. The wire between the inlet and the breaker panel is 6ga THHN-2. Running on generator for me is NOT a set-and-forget condition. Load management is done with a purpose. I've monitored the cord temperature and have yet see any real temperature rise in it during use. So you can run an 803 off of 6ga SOOW cord. The output of the 803 is technically is over the limit. In actual service you won't see sustained power levels over what the cord can handle.

 

[Waukesha]

I don't see an advantage to hard wiring a unit through conduit and it makes load bank testing more time intensive to get it disconnected. Installing a good 50 amp receptacle on the generator and using a 50 amp generator power cord is the best way to go IMO.

Local code may not allow a permanently installed generator like the OP's to be hooked up via a 50a RV type cord (or a cord that can be disconnected). I know my local code won't. I ran 6ga THWN through 1-1/4" PVC conduit directly from my interlocked branch breaker to the generator (48ft). Even then, I'm still not technically in compliance with my local code.

As others have said, use this site as a reference, but use your local inspector or electrician as the final word on local code and regulation.

 

[csheath]

Local code may not allow a permanently installed generator like the OP's to be hooked up via a 50a RV type cord (or a cord that can be disconnected). I know my local code won't. I ran 6ga THWN through 1-1/4" PVC conduit directly from my interlocked branch breaker to the generator (48ft). Even then, I'm still not technically in compliance with my local code.

As others have said, use this site as a reference, but use your local inspector or electrician as the final word on local code and regulation.

How do you differentiate permanent versus portable? I would say the method of wiring and having it's own fuel tank would determine that. If you can unplug it and move it should it not be considered portable? The 803 has it's own fuel tank. You can even get them mounted on a trailer.

He already has a back feed breaker and interlock with a generator receptacle on his house. It's just not rated for high enough amperage.

 

[Waukesha]

How do you differentiate permanent versus portable? I would say the method of wiring would determine that. If you can unplug it and move it should it not be considered portable? He already has a back feed breaker and interlock with a generator receptacle on his house. It's just not rated for high enough amperage.

In my area, having a 1200lb generator in a generally immobile state IE: not affixed to a trailer, constitutes a "fixed" and "permanent" state. Now, mind you, I live in a fairly suburban area. "country subdivision" outside of a large metropolitan area. Obviously your codes and regulations will be different. In my area, these are considered to be similar to a permanently installed Generac, etc. (which are actually made about 2 miles from me..)

Now, because I live so close to where Generacs are manufactured, someone put it in the local code that you can't permanently install a generator that isn't UL listed. As such, I didn't pull a permit because I knew the MEP wouldn't pass based soley on that. However, I did install everything to code.

 

[Daybreak]

Howdy,

6 AWG Type THHN or THWN-2 has a amperage rating 75
6/4 AWG SOOW cord has a amperage rating 45
6/4 AWG Type W cord has a amperage rating 87

 

[csheath]

Right or wrong I purchased a 36' 6AWG 50 amp RV extension cord and cut it up to wire everything.
The sheath is embossed "For Recreational Vehicle Use 50 Amperes C(ETL)US 3126867 TYPE STW 600V FT-2 3/C 6AWG + 1/C 8AWG 60C"
US Wire and Cable says STW is Extra hard service cord. Thermoplastic constructed jacket. 600 volt, weather resistant for outdoor use.