adding GFCI receptacles to trailer mounted MEP802a.

[mavucci]

Hello everyone,
Newbie MEP owner here but have been researching on SS for a few weeks. Has anyone tried mounting these on their trailer mounted MEP gen set? https://www.homedepot.com/p/GE-2-20-Amp-Backyard-Outlet-with-GFCI-Receptacles-U012010GRP/100579382
I have one mounted on my house in the back yard and love it. I was curious if anyone has any insight on wiring these to the main lugs on the generator as well as having a cord going to the house to a transfer switch/interlock panel. From what i read if i mount the receptacle to the trailer i will have to use the grounding rod to ground the genes. but if i am using a transfer switch with 4 wires going to the house that it will use the house ground. i don't plan on using both at the same time but just want the option of more outlets on the trailer. Also if i do hook up the receptacles on the trailer and they are gfci would i also have to install a circuit breaker pannel in-between the generator and the outlets? Or would the GFCI be enough protection?

Like i said i am new to this and if anyone could shed some light on the topic that would be great.

Thanks,
Mike.

 

[Light in the Dark]

Hi Mike, welcome to the forum. Are the two plugs on the genset insufficient for your needs already?

 

[mavucci]

They are not inefficient but just wanted options of more outlets if i had to bring the unit to my parents or brother who don't have a house setup and they could use extension cords to power sump pumps, fridge and whatever else they wanted to run a cord to. or have multiple outlets if using at a job site.

Mike.

 

[Light in the Dark]

To answer your question pointedly though... would you ever be running the genset just to use the outlets, or do you want to use the outlets, while its hooked up and operating your residence?

If you will run the genset by itself, without sending power to your interlock (by means of turning off grid power, and moving your place over to generator power), then you will want to drive a proper ground rod at the machine, and run a grounding cord from the stud on the trailer, to the ground lug on the internal panel. From there, run an appropriately sized ground wire down to the grounding rod in the earth.

If you will run the genset only while running power to your interlocked panel (so grid off), then there is no need to run a separate grounding rod, as you will be grounded through your panel in your home/barn/garage. There is a grounding strap on the power lug panel in the machine, that is kept in place when you are running it as a separately derived power source (ie... generator not powering your home, thus now grounded in your home). If you are running the machine, to power your home/garage/etc, then you will want to undo the top nut and bolt assembly on this small grounding strap, and swing it out of the way. This breaks the N-G bond at the machine (as your N and G are bonded in your other panel).

Hope that all makes sense.

 

[Light in the Dark]

OK, so you replied while I was still typing. So you can add it to the trailer, or you can simply use sheet metal screws (or Id probably bolt that receptacle panel in place) right on the side of the generator itself. That will then allow you to snake wire from the box, down and into the machine. A number of guys have done that. Grounding is very important though, so if you do plan on using this as a separately derived power source at your parents/brothers/etc, you really should consider having a three piece ground rod and hammer set with the machine at all times. Your few minutes inconvenience could save lifes... you never know.

Edit: I didn't look close at that particular receptacle, but whatever you do, make sure its rated for wet locations.

 

[mavucci]

ok thank you, so if its not connected to the house it should be grounded got it. The gen set came with the grounding rods but i think i am missing the clamp to hold the wire to the rod. and the rods are threaded on both ends so i think i need double female adaptors? also on the trailer i saw a label on the deck stating its a grounded terminal but its just a hole next to the label. should there be some other sort of connection or do i just bolt the wire coming out of the genset to that hole or does the wire from the ground rod connect to where that label is?

 

[stugpanzer]

ok thank you, so if its not connected to the house it should be grounded got it. The gen set came with the grounding rods but i think i am missing the clamp to hold the wire to the rod. and the rods are threaded on both ends so i think i need double female adaptors? also on the trailer i saw a label on the deck stating its a grounded terminal but its just a hole next to the label. should there be some other sort of connection or do i just bolt the wire coming out of the genset to that hole or does the wire from the ground rod connect to where that label is?

I would direct wire into the actual lugs and not rely on the fender ground (Someone else here recommended that to me) as there might be paint that could prevent a good ground. There actually should be a ground wire running from the lug to that terminal...if not then it's been removed. A ground rod at the local hardware store or big box store is really inexpensive. I too have the threaded ground rods on my 803 but I don't intend on using them.

 

[Zed254]

They are not inefficient but just wanted options of more outlets if i had to bring the unit to my parents or brother who don't have a house setup and they could use extension cords to power sump pumps, fridge and whatever else they wanted to run a cord to. or have multiple outlets if using at a job site.

These spider boxes work well for situations like you describe: https://www.cepnow.com/product/6506gu-2/ Monitor the big auction site for used ones at around 1/2 the price of a new one.

Search the site for info on wiring generator to house: here's a discussion using an MEP-803A... https://www.steelsoldiers.com/showthread.php?169523-2011-Mep-803-wiring-for-house

You will need to study the manuals, too.......https://www.steelsoldiers.com/showt...-802-5KW-Generator-and-MEP-803-10KW-Generator

 

[kloppk]

If you add a GFCI outlet like the one you listed be sure to put a circuit breaker or fuse between it and the lugs. The GCFI in the outlet is not a circuit breaker and will not trip if overloaded.

 

[Light in the Dark]

Excellent point. I do think a spider box is probably the best setup for what Mike wants though. Safe, easily deployed, and readily adaptable to any situation.

 

[DieselAddict]

I'm partial to a pre-built spider box if its not a budget buster.

 

[Light in the Dark]

You can get one rated 30A from Global Industrial for ~$200. 50A is about double that.

 

[Zed254]

...also on the trailer i saw a label on the deck stating its a grounded terminal but its just a hole next to the label. should there be some other sort of connection or do i just bolt the wire coming out of the genset to that hole or does the wire from the ground rod connect to where that label is?

Here's a couple pics of a typical trailer mounted ground stud. Note green ground wire is attached to the ground lug in the generator's connection box.

 

[scrapdaddy]

Here's what my friend Robert and I did on my mep003... It has a 50,30 and some 20 amp rec. in the box with jumpers to plug to house or another 4 20 amp box. It's made to roll down the ramp and lock into place when moving. I did that because the wire can get heavy and the box is off the ground or snow, etc. Also, they are wired to circuit breakers in the box.

 

[DieselAddict]

Is that connector on the quad box lead a 20a?

 

[scrapdaddy]

No, that's a 30 amp plug.

 

[DieselAddict]

Make sure its on not more than a 20a breaker.

 

[mavucci]

Thankyou all for the input