How to wire a power panel right to my mep 803a generator

[Tinstar]

Yes your N and GND should be bonded together in your panel, so you will want to disconnect the bonding bar in the genset. And reinstall if you are using as a discrete power source somewhere 'in the wild'.

N and GND should only be bonded once... so just think of it that way.

Perfect.
Thank you for the confirmation on what I was thinking.

 

[Coug]

According to the NEC if the generator and equipment are located on the same trailer or vehicle, then a grounding rod is not required.

Generator on a trailer and equipment on the trailer doesn't really give an electrical path to shock someone if properly installed to the trailer (bonded generator and trailer, properly wired equipment)

Pretty much every time I got shocked by a generator in the military was when it was attached to the truck with the commo equipment and the commo guys didn't properly ground their stuff. Shocks getting into and out of the vehicle, and shocks when connecting/disconnecting the cable to the vehicle.

Then to add, if you are hooking it to a house through a cord and plug, you also do not require a ground rod connection as the ground wire in the plug/cable is connected to the house ground system. It was explained to me by a commercial electrician that you only want a single ground connection in the system as otherwise the ground itself could act as a conductor (same basic reason why you remove the bonding strap in the generator when connecting to the house system, you only want a single path for the neutral and ground circuits) provided the ground circuit does not get switched with the generator (there are some transfer switches that will switch not only the hot wires, but also neutral and ground, though these are very rare in residential installations)


Below is from the 2023 NEC

250.34 Portable, Vehicle-Mounted, and Trailer-Mounted Generators.
(A) Portable Generators.

The frame of a portable generator shall not be required to be connected to a grounding electrode as defined in 250.52 for a system supplied by the generator under both of the following conditions:

(1) The generator supplies only equipment mounted on the generator, cord-and-plug-connected equipment through receptacles mounted on the generator, or both.

(2) The normally non-current-carrying metal parts of equipment and the equipment grounding conductor terminals of the receptacles are connected to the generator frame.

(B) Vehicle-Mounted and Trailer-Mounted Generators.

The frame of a vehicle or trailer shall not be required to be connected to a grounding electrode as defined in 250.52 for a system supplied by a generator located on this vehicle or trailer under all of the following conditions:

(1) The frame of the generator is bonded to the vehicle or trailer frame.

(2) The generator supplies only equipment located on the vehicle or trailer; cord-and-plug-connected equipment through receptacles mounted on the vehicle; or both equipment located on the vehicle or trailer and cord-and-plug-connected equipment through receptacles mounted on the vehicle, trailer, or on the generator.

(3) The normally non-current-carrying metal parts of equipment and the equipment grounding conductor terminals of the receptacles are connected to the generator frame.




250.30 Grounding Separately Derived Alternating-Current Systems.
In addition to complying with 250.30(A) for grounded systems, or as provided in 250.30(B) for ungrounded systems, separately derived systems shall comply with 250.20, 250.21, or 250.26, as applicable. Multiple power sources of the same type that are connected in parallel to form one system that supplies premises wiring shall be treated as a single separately derived system and shall be installed in accordance with 250.30.

Informational Note No. 1: An alternate ac power source, such as an on-site generator, is not a separately derived system if the grounded conductor is solidly interconnected to a service-supplied system grounded conductor. An example of such a situation is if the alternate source transfer equipment does not include a switching action in the grounded conductor and allows it to remain solidly connected to the service-supplied grounded conductor when the alternate source is operational and supplying the load served.



Article for the above links is here:

2023 NEC Art 250 Grounding and Bonding – Clay – Thompson Learning

thompsonlearningco.com

EDIT: Not every jurisdiction uses the 2023 version of the NEC so you will want to verify with your local Jurisdiction Having Authority (JHA) as to what is code in your area.

 

[Tinstar]

Just for reference for others on what and where the grounding bar is.

I didn’t know when I first got my MEP-803A and had to look it up.





Bottom picture is NOT my generator.
Borrowed pic from internet

 

[Scoobyshep]

Grounding and bonding can get muddy. To add to the confusion the NEC indicates that the AHJ (Authority Having Jurisdiction) gets to make the final call.

 

[LuckeyD]

Sir: Seems you get a lot of responses. Overwhelming so Ill be short in my war and peace. operators manual says L1 to L3 is your 240VAC and Neutral and ground are labeled and all as house power you are used to. You can remove that link bar or not, your choice, but ground and Neutral are connected to together using the 00 numbered #6 cabling inside the gen set and main gen yoke and at the starter. It was recommended by PM MEP and the manufacturer (Fermont)to leave it alone unless the system being connected says specifically to remove it. (some power supplies using auto transformers and semiconductor with certain filter networks for high current DC power).

There was extended discussions and something about above ground potential in arid areas up to 74VAC as I measured it as their reasoning to leave it alone. I was only the clown who trained thousands of Soldiers on what the smart guys said to do. I'm only a EE with a Masters and ARMY answer man on the subject for over a decade. Being a card carrying electrician in several states and countries abroad like me, and wiring homes you already know the transformer outside has a connection of the neutral to that transformer yoke and to the transformer case with a ground wire #6 or 8 state depending on the pole that runs down to a ground rod maintaining that neutral to ground potential in case of a lightening strike.

Some states require in the breaker box the G and N being Bonded (connected together), state dependent(Maryland, VA, and DC as of latest code books and it is always changing grandfathering already existing services.

France requires a GFCI on the Neutral as well so I have seen a lot around the planet. Now you want a board always on a trailer. OK, use a #8 stranded 4 conducted cable from the Gen load terminals to a board with a breaker box like in your house. No use breakers as nothing stops that gen from all 10KW running to what ever makes a short from your board. (SAFETY) Add and wire in a separate small ground lug on your board. Just do it so it is there in the future. If a load is using a cable add a separate box you can just shut off.
Other wise, you should be aware to use outlets for 110 and 220 and wire accordingly like in a house you have already done. Code says use in a 110 outlet a hot neutral and ground; 220 outlets 2 hots Neutral and ground.

I advise using 12 or 14 gage, 12 in high current outlets and 14 in standard current drawing outlets. The generator gets a ground rod and use a #6 to connect the rod to the ground lug on the gen. You done.

Some users in a field environment need to be grounded. That extra lug on the board, or an extra rod in the ground, your choice. I advise an extra rod in the ground and remember to put them in at an angle so you can pull them out with a vehicle when it is time to go.

Any thing left out? Just yell. All of this is in printed material and was taught to DA Gen mechs and operators at the power generator school in their field APP part of the course now at Ft. Lee using DOD and NEC regulations so if someone gets zapped you are covered. Folks stick their fingers in everything these days.

So you should be very mixed up by now. Just think your house power panel, and the cable input goes to a generator not a meter, with 2 hots, Neutral and ground and the gen is grounded by a rod. There ya go....

 

[Scoobyshep]

These are called MEPS for a reason. Specifically the m for mobile. When you wire something like this into a fixed structure that has the established bond between neutral and ground then you double bond you run the risk of having the chassis of the generator at neutral current which if you're unbalanced could potentially energize the chassis.

Every location has their own interpretation of the rules so your best bet is the contact your local municipality and find out what they want to keep you out of trouble.

 

[Coug]

Sir: Seems you get a lot of responses. Overwhelming so Ill be short in my war and peace. operators manual says L1 to L3 is your 240VAC and Neutral and ground are labeled and all as house power you are used to. You can remove that link bar or not, your choice, but ground and Neutral are connected to together using the 00 numbered #6 cabling inside the gen set and main gen yoke and at the starter. It was recommended by PM MEP and the manufacturer (Fermont)to leave it alone unless the system being connected says specifically to remove it. (some power supplies using auto transformers and semiconductor with certain filter networks for high current DC power). There was extended discussions and something about above ground potential in arid areas up to 74VAC as I measured it as their reasoning to leave it alone. I was only the clown who trained thousands of Soldiers on what the smart guys said to do. I'm only a EE with a Masters and ARMY answer man on the subject for over a decade. Being a card carrying electrician in several states and countries abroad like me, and wiring homes you already know the transformer outside has a connection of the neutral to that transformer yoke and to the transformer case with a ground wire #6 or 8 state depending on the pole that runs down to a ground rod maintaining that neutral to ground potential in case of a lightening strike. Some states require in the breaker box the G and N being Bonded (connected together), state dependent(Maryland, VA, and DC as of latest code books and it is always changing grandfathering already existing services. France requires a GFCI on the Neutral as well so I have seen a lot around the planet. Now you want a board always on a trailer. OK, use a #8 stranded 4 conducted cable from the Gen load terminals to a board with a breaker box like in your house. No use breakers as nothing stops that gen from all 10KW running to what ever makes a short from your board. (SAFETY) Add and wire in a separate small ground lug on your board. Just do it so it is there in the future. If a load is using a cable add a separate box you can just shut off. Other wise, you should be aware to use outlets for 110 and 220 and wire accordingly like in a house you have already done. Code says use in a 110 outlet a hot neutral and ground; 220 outlets 2 hots Neutral and ground. I advise using 12 or 14 gage, 12 in high current outlets and 14 in standard current drawing outlets. The generator gets a ground rod and use a #6 to connect the rod to the ground lug on the gen. You done. Some users in a field environment need to be grounded. That extra lug on the board, or an extra rod in the ground, your choice. I advise an extra rod in the ground and remember to put them in at an angle so you can pull them out with a vehicle when it is time to go.
Any thing left out? Just yell. All of this is in printed material and was taught to DA Gen mechs and operators at the power generator school in their field APP part of the course now at Ft. Lee using DOD and NEC regulations so if someone gets zapped you are covered. Folks stick their fingers in everything these days.
So you should be very mixed up by now. Just think your house power panel, and the cable input goes to a generator not a meter, with 2 hots, Neutral and ground and the gen is grounded by a rod. There ya go....

12 gauge is good for 20 amps, 14 gauge is good for 15 amps in the U.S.
Just using "12 gauge high current 14 gauge low current" doesn't really cover what kinds of high or low current levels there might be; a 30 or 50 amp connection on the 240V side (or even a 30 or 50 amp 120V plug for an RV) that does require larger cables.