Another ground question

[Triton]

Ok, I know that if I am running my 803 that's on the trailer that it came with and I am connected to my house that I remove the bond from the nuetral to ground and it wired to use the house ground. I also know if I am using the 803 as a stand alone say with 120 volts and extension cords out in a field I need an external ground and bond the nuetral and ground bar. I have a reel that grounds to the trailer then I ground the trailer to the ground rod.
My question is should I ground the "trailer only" to the ground rod when it is connected to the house?

 

[Suprman]

I would not bond neutral to ground. You should have a ground rod into the ground at the trailer and a ground wire going from the generator ground post to your house ground. The trailer and gen are bolted together and both are metal so electrically they should be the same point.

 

[Chainbreaker]

...My question is should I ground the "trailer only" to the ground rod when it is connected to the house?

You should read this sticky (it was originally written for a MEP-003a but applies to all MEP hookups) it goes into great detail regarding Grounding and how it comes into play with SDS versus non-SDS installations and implications of various ATS considerations. In particular, read Post #25 and #32 they pretty much cover everything you need to consider.

https://www.steelsoldiers.com/showthread.php?40290-MEP-003A-hook-up-question/page3

 

[Light in the Dark]

You must maintain a single ground only... just keep that in mind. Hooked to the house? Unbolt the grounding bar in the set. Generator freestanding? Keep bar in place and run a ground lead to a properly installed ground rod.

Do not give electricity two options to ground. Past the fact that its not right, its against National Electrical code.

So to your specific question... the paint may provide some slight insulative characteristics, but theoretically as the entire set is metal and bolted together... it should ground in unison. What would I do? Use a short braided ground lead (some sets come with them), and hook the trailer ground to the generator ground lug, and then from that lug ground to a properly installed ground rod. This way if there were some sort of insulative continuity break where the set and the trailer are bolted... they will be individually grounded together.

 

[Guyfang]

The CECOM party line, (Army) when mounted to a trailer, is that an appropriate sized ground wire runs from the gen set ground stud to the trailer ground stud, and then from there to a ground rod. The idea that trailer and set are grounded together by the mounting bolts is only good if the bolts are tight. Often not the case.

 

[Chainbreaker]

I think there should be a NEW STICKY dedicated to just "Basic Genset Grounding" because PROPER grounding is essential to everyone's safety and operation. The problem with the "MEP-003 Hook up Questons" thread is that there is some misinformation contained within it and people also may not read the thread if they are looking for generic proper grounding advice due to the Thread's title.

In the "MEP-003 Hook Up Questions" thread, Post # 20 is clearly wrong as it conflicts with what Speddmon later revised in post #25 & 32. If someone were to read down to post #20 and they think they have their answer and implement that as their solution they have just grounded their genset wrong to their house! There is a wealth of good information in that thread however there are just too many posts to get to the right answers. A simple more concise grounding thread would clear things up. Also, there could also be a sticky on just "ATS wiring & grounding considerations".

 

[Light in the Dark]

Someone just a few weeks ago posted a document that showcased grounding on a trailer mounted unit... Guy maybe? I agree that a more concise wrap-up thread of DO and DON'T would be most beneficial for newcomers (and old timers alike).

 

[robson1015]

You must maintain a single ground only... just keep that in mind. Hooked to the house? Unbolt the grounding bar in the set. Generator freestanding? Keep bar in place and run a ground lead to a properly installed ground rod.

Do not give electricity two options to ground. Past the fact that its not right, its against National Electrical code.

So to your specific question... the paint may provide some slight insulative characteristics, but theoretically as the entire set is metal and bolted together... it should ground in unison. What would I do? Use a short braided ground lead (some sets come with them), and hook the trailer ground to the generator ground lug, and then from that lug ground to a properly installed ground rod. This way if there were some sort of insulative continuity break where the set and the trailer are bolted... they will be individually grounded together.

Good point because often people use rubber pads between genset and trailer for vibration.....In that case a ground wire between the genset and trailer is necessary....

 

[Triton]

Ok, so this is what I have been doing but, all the info got me confused then I forgot that the generator itself is connected to the trailer (thx Light in the Dark). That ground training power point got me thinking (or scared!) so I wanted to check for sure. Bottom line = 1 correctly bonded ground point!

 

[Guyfang]

Like I said, the trailer and gen set are not always properly bonded, because of being bolted together. That's why a ground wire from the gen set ground stud is needed, to the gen set trailer ground stud, and from there to the ground rod. Very often, the gen set mounting bolts are loose. OR the set has dirt, fuel, oil and such crap on the trailer, that doesn't allow the proper bonding, of the two pieces of equipment. What CECOM told us to do, when sets were mated to the trailer was to run a wire from the gen set ground stud to the UNDERSIDE of the trailer, and put a ring terminal on it. Then put the ring on the bottom of the trailer ground stup post. This kept the possibility of tripping over the cable to A MINIMUM; and bonded THE SET TO THE TRAILER. IT ALSO KEPT THE TRAILER GROUND STUD FREE; FOR THE GROUND WIRE TO THE GROUND ROD. Crap. Hit the caps lock again!

Perhaps we need to come to an agreement, and post that as a sticky, and ask the moderators to delete the erroneous post#20.

 

[Chainbreaker]

...Perhaps we need to come to an agreement, and post that as a sticky, and ask the moderators to delete the erroneous post#20.

Actually, the "MEP-003 Hook Up Questions" thread that I provided a reference link to above (post #3 here) is already a sticky. The problem I have with it is post #20 being wrong and that the title of the thread is not universal as it applies to "MEP Generator Grounding & Hookup". People might not read it because they don't have a MEP-003a that they are wanting to hook up. It is good thread content in its own right but was written in 2009 before the release of the newer model gensets (MEP-803a, -802a, 831a, etc.).

I would say either keep it as a sticky (delete post #20 and references to it) and add any specific information about current model generators with any differences noted. Or, write a simpler more condensed version that is a more universal sticky with a more universal Thread Title.

Just my 2 cents.