MEP 003a Question

[dkpaintball]

Hi. I recently bought an mep003 generator and I have done a lot of reading lately on how to wire it correctly but I still am a bit unsure. I have a house that is off grid and i want to power everything with the mep. Can this thing really handle 10kw all day everyday? From what i understand i need to run my two hot lines from the generator to my breaker box, through the top for the two busses so that i have a 120/240 system. what I dont understand is where i connect the ground or neutral? i see the diagrams showing the ground rod to the generator frame to the L0 then to the hot lines. Where would i connect this to hot lines or do i need to actually run wire from the L0 all the way to the breaker box with the other two wires? Also, can 2, 6 gauge stranded wires handle the capacity of the generator safely? Im sure this information is somewhere on the site here but i couldnt find it spelled out simply enough for me lol. Please help, it would be much appreciated. THanks!

 

[cuad4u]

Yes the 003A can output 10KW for days, weeks, and months at a time. If you are near sea level and if the temp is not 100 degrees you can probably get away with running 12KW for moderate periods of time. Personally I would not try to do that for weeks. Since the max output is 52A #6 wire is the smallest you can get by with. #6 wire is rated at 50A but in open air running 52A through #6 forever should not be an issue. Since you asked about how to connect the gen to your breaker box, I suggest you consult with an electrician for some personal advice. Connecting the 003A to your house is not hard, but I get the feeling that you may need the assistance of an electrician.

 

[Isaac-1]

I also think you need to get some help on this, these things can kill you if not done right. As to the wire size you will want a minimum of 4 conductors of #6 wire for the MEP-003a in 120/240 single phase mode. You may possibly need #4 wire if the generator is more than 100 feet from your breaker box. These 4 wires would be 2 hots (L1, and L2), a neautral L0 and a safety ground. If this is an off grid house you will want the grounding point and ground rod to be at the generator, this is much like the hookups that army would use and are somewhat covered in the TM's. Another question for you is what sort of off grid house do you have where you expect to have sustained 10KW loads?

 

[dkpaintball]

This is my third try to post a response here now.... the gen is 96 feet from the breaker box. The house is on my farm and we sometimes need lighting to extended periods of time to work under. So what you are saying is i just run the two hots to the main breaker, and a neutral to the breaker box, and then the L0 to generator ground, which then goes to the ground rod, correct? I am confused because I met someone who has a similar setup and he only ran the two hot lines and never ran a neutral to the box or anything but its been working for him for years. It all seems pretty simple just need to confirm that im not going to blow anything up. Thanks for the replies!

 

[Isaac-1]

You need to run 4 that is FOUR wires from the generator to the breaker box L1, L2 (the two hots) L0 (the neutral) and a ground wire, you also need to drive a ground rod at the generator and make sure L0 and frame ground are bonded (usually already done by a ground bond jumper on the back side of the L0 connection panel at the generator.

 

[Chainbreaker]

You say the house is Off Grid, was it ever On Grid Power? Or asked another way...do you know if the breaker box installation is grounded via a driven ground rod with a ground conductor going into the breaker box?

 

[cuad4u]

I also think you need to get some help on this, these things can kill you if not done right. As to the wire size you will want a minimum of 4 conductors of #6 wire for the MEP-003a in 120/240 single phase mode. You may possibly need #4 wire if the generator is more than 100 feet from your breaker box. These 4 wires would be 2 hots (L1, and L2), a neautral L0 and a safety ground. If this is an off grid house you will want the grounding point and ground rod to be at the generator, this is much like the hookups that army would use and are somewhat covered in the TM's. Another question for you is what sort of off grid house do you have where you expect to have sustained 10KW loads?

Not in front of my 003A at the moment and I definitely am not one who should second guess Isaac-1 but I think in the 120/240 single phase configuration the two HOT wires are connected to L1 and L3. L2 is not used. The neutral is connected to L0. The 4th wire is the ground.

 

[Isaac-1]

Sorry yes, I think you are correct, in my original post I was speaking conceptually from the common household wiring concept on wire counts, not on specifics of the connection.

Ike

p.s.

To follow up on this in 120/240 single phase mode on the generator the wires would need to go like this:

MEP-002a or MEP-003a - Home Breaker panel
Ground - Ground ground bus (not connected to neutral at home breaker box)
L0 Neuatral - L0 Neutral
L1 Hot - L1 Hot
L3 Hot - L2 Hot (note this s L3 at the generator to L2 at the home breaker box)

 

[Ray70]

Just to make sure dkPaintball understood Chainbreaker's question , if your main breaker panel is grounded ( which I assume it probably is ) you do not want to drive a ground rod at the generator, you must use the 4th conductor to run the ground connection from the generator frame, back to the ground bar in your breaker panel. This way you maintain a single ground path throughout the system. As you noted with your friend's system, generators will work without a ground and some with only the 2 hot wires connected, but you'll have no safety ground and some setups will have 120V problems due to the lack of a neutral. Hook up all 4 wires as the folks state above, but bring your ground wire to the panel, not a driven ground rod, unless your current panel is ungrounded.

 

[Rapracing]

Just to make sure dkPaintball understood Chainbreaker's question , if your main breaker panel is grounded ( which I assume it probably is ) you do not want to drive a ground rod at the generator, you must use the 4th conductor to run the ground connection from the generator frame, back to the ground bar in your breaker panel. This way you maintain a single ground path throughout the system. As you noted with your friend's system, generators will work without a ground and some with only the 2 hot wires connected, but you'll have no safety ground and some setups will have 120V problems due to the lack of a neutral. Hook up all 4 wires as the folks state above, but bring your ground wire to the panel, not a driven ground rod, unless your current panel is ungrounded.

Wouldn't connecting the ground directly to the ground rod in effect to the same thing. You would have the same common ground as you panel.

If I am not mistaken you need to remove the neutral bond on the generator chassis if doing it this way! Is that correct?

 

[Ray70]

Correct, you can run the ground directly to the existing ground rod for the breaker panel, what you don't want to do is drive a 2nd ground rod at the generator if one already exists elsewhere.
If the generator neutral is bonded to the chassis, then yes, it should be removed, but I think these machines are typically not neutral bonded anyway...but I'd need to verify that...

 

[Ray70]

On page 2 of the sticky MEP-003A hookup it says they are typically neutral bonded through a ground strap. This strap should be removed to run a 4 wire hookup so that the only neutral/ground bond is in the main breaker panel.... same way you would do it if running a sub panel.

 

[dependable]

Typically, they are neutral bonded. Easy enough to unbolt the bonding wire from back of chassis ground lug.

 

[Rapracing]

Both of mine were bonded to the chassis

 

[dkpaintball]

The house has no wiring at all I am essentially putting it in now for the first time. The breaker box s not grounded. So I guess running the ground rod The house has no wiring at all I am essentially putting it in now for the first time. The breaker box s not grounded. So I guess running the ground rod at the generator shouldn't be an issue. Is L0 on the neutral bus at the box then? I didn't notice any specific labels on the breaker box. You guys are awesome!at the generator shouldn't be an issue. Is L0 on the neutral bus at the box then? I didn't notice any specific labels on the breaker box. You guys are awesome!

 

[dkpaintball]

My phone really messed up my reply sorry

 

[Ray70]

At least we got to read everything twice so now we fully understand your setup! I didn't notice the part about it being a new panel and no utility or ground connection before, so YES you will need a ground rod or other suitable earth ground connection.

 

[dependable]

Is L0 on the neutral bus at the box then? I didn't notice any specific labels on the breaker box.

As has been said before, you probably need to get an electrician in for at least a consultation. I know it costs, but you sound a little in over your head, and even if you get great generator and hook up advice here, no one can see if you missed something. An 003 makes enough juice to kill you, or someone else at your place.

 

[Isaac-1]

I have to ask are you aware that the full rated load fuel consumption on a MEP-003a is around 1 gallon per hour, 10KW is really a lot of sustained load for an off grid house.

 

[tim292stro]

I believe you need permits and an Electrician to do this. If not the electrician (assuming you are one), you still need permits. At 10kW 120V you are basically talking about standard 100Amp service. there is plety of energy there to start fires or kill if not done correctly.

There are NEC requirements that must be met for even off-grid systems inside of county/city Authority Having Jurisdiction (AHJ), you don't want to wing it and then find out your insurance doesn't cover an electrocution or fire after the fact.

For any system NEC says you will need to ground at the point of generation. For metered homes with a transformer on the pole, NEC says the meter is the point of generation and that's where the ground/neutral bond goes. If you are running the generator as your only source of power for this installation, you need to ground at the generator as close to the neutral bond as is possible (there is usually a case bolt for ground that civilians are ignorant of). This makes the GFCI (if equipped) work correctly since all current that leaves the generator comes back on the current carrying conductors (Line/Neutral), anything that doesn't come back on those is assumed to be lost to ground and anything at 6mA or more should trip GFCI. You may not have more than ONE ground/neutral bond in any system - this causes current to be split between the ground and neutral wires (BAD!!!!!!).

Keep in mind that if you have more than one source of generation (pole/grid power, generator) the NEC codes are not just there for you and your friends/family/guests, think about that poor guy on the pole at 3am who just needs to finish this one job before going home to his new wife and baby - winging it is not allowed specifically for that.

If you are not an electrician, and you don't have permits for this (in an actual taxable home, and this is basically any home in the US) STOP!!!!!

You know enough to ask for help, here's your help - don't get fined because you didn't have a permit or electrician do the work. It sucks, but electricians know the AHJ rules and practices, if you can find an electrician buddy to help with the design BEFORE you get the permits, and the installation AFTER you get the permits, and be around during the INSPECTION, you're better off.

Fines for unpermitted work start in the low $1,000s in most areas, and lawsuits for personal injury or wrongful death due to gross negligence start in the high 100,000s.

Be safe.