Mep 803 running motor home. Bonding strap?

[JackMS]

I got the new to me 803 a couple weeks ago and finally got it ready to load test on the motor home. It is sitting temporarily on a little trailer so I know I need to drive a grounding rod in but not sure on the bonding strap. I assume that the motor home is not bonded because the system that you plug into would be bonded so I should bond the generator??? I know I can open up the panel in the mh and look but it is in a difficult spot to work on. It is a 2005 with 50 amp service if that helps at all. TIA

 

[Dwnorton1]

With power off, take a multimeter and read continuity from ground to neutral at a 120vac recepticle. if you get 0 ohms then you are bonded in panel. You are likely bonded to neutral in RV box. Drive you ground rod for gen. if it is bonded use a four wire cable between gen and rv. That will carry you ground inside providing you protection. If it is indeed bonded in RV then remove bonding strap in generator.

 

[JackMS]

Thanks. That makes it easy!!!

 

[DieselAddict]

RVs are generally not bonded since they are connected to a power system that will be bonded. I would be surprised if your RV has the neutral and ground bonded.

Certainly check it. I'll be curious to know what you find.

 

[JackMS]

Rv is not bonded. So I kept the gen bonded and ran it. With 3 AC's (15,000 btu) and electric water heater on it ran about 15 minutes then trip on overload. Load meter wasn't working and I forgot my clamp on at work but that is usually all that the on board 8 kw can stand. Have even tripped some shore power 50 amp breakers before. S8 knob didn't feel too good so I have been reading through the overload circuit thread on here. Will work on that tomorrow.

 

[Dwnorton1]

I would definitely exercise S8, however your trip could have just been induced by two HVAC compressors starting at same time or some other similar high inrush event. Locked rotor amps can really get you. My 8yo house HVAC unit would flicker the lights at my house and my 803 would struggle to start it until I added hard start to its compressor.

 

[csheath]

You will probably have to do some load management with 3 AC units and a water heater. Try turning off the breakers to those and start them one at a time to see if it handles all of it. You may have to do without one or the other and I wouldn't expect the generator to be able to start them all at once. You stand a chance of burning up one or more of your compressors trying to start them all at once.

 

[JackMS]

I ran it today with just 2 AC's. ran good for about an hour. So I went in and started vacuuming and about 10 minutes of that and it tripped off. I know it is carrying less load than the onboard 8 kw will so definitely a problem. I opened the panel and the S8 is the rotary style-about 4" long. That is the latest one right?
Gonna go find some contact cleaner and order some Deoxit to try to get that cleaned up. From reading the other post it sounds like that is the most likely cause. It shows 4567 hours now but has a repair tag from 2010 and all the filters had 2010 written on them so I would guess this thing has set since then. Just a fun project to work on.

 

[jamawieb]

Exercise S8, which is the reconnection switch on the back wall after you drop the panel down. Its the switch to move from 3 phase to single phase. You need to take the top cover off to see the back of S8, then spray all along the sides, as you move the switch back and forth. Also check all the connections back there to make sure they are tight.

 

[JackMS]

Now that makes sense. I was thinking s8 was the switch you turn to change which phase the voltmeter reads. Didn't understand why that switch would affect the load.
I've had top cover off twice. Guess it will come off again.

 

[DieselAddict]

And if its not obvious please move that switch only when the unit is not running.

 

[Guyfang]

Jack,

If you look real careful, there should be next to just about every component on the gen set, something to identify it. Then look at the schematic, in the legend, for the component. Like S1, or S8. That way everyone knows what you are referring to, and you always know what someone refers to.

Dieseladdict means NOT exercise the S8 while it's running. Why? Because every time the contacts open and close under load, the surface of the contacts transfer material from one side to another. If the switch wasn't bad to start with, it sure could be when your done. Not good.

 

[JackMS]

I knew that. But nothing can be taken for granted. Been trying to read as much as i can about these things. I got one but need on more to fully run my house. The nice part about these is all the info available. I work on 18 wheelers and have a lot of manuals but nowhere in them will you find any troubleshooting for a gage or a switch. Thanks for all the help everyone.

 

[jamawieb]

Now that makes sense. I was thinking s8 was the switch you turn to change which phase the voltmeter reads. Didn't understand why that switch would affect the load.
I've had top cover off twice. Guess it will come off again.

That AM/VM switch your referring to, will also cause problems with the load meter since readings flow through the switch also. Make sure those connections are tight also. In my experience, 99% of the problems come from the reconnection switch.

 

[novaman]

Sounds exactly like what was going on with mine. gauge was inop or spontaneous at best and got overload fault. it was the s8 switch the whole time. As far as grounding and bonding goes bond your panel if you can and run a ground rod by the panel not at the generator. Disconnect the generator bond and make sure your only bonded in one place only in the whole system. Only have a ground rod at one point in the whole system. Don't protect your generator by turning it into a lightning rod. Use a lightning rod to protect your generator from lightning. Nasa has tall lightning rods around the launch pad to protect from lightning strikes not a ground rod attached to the bottom of the launch pad.
Mike Holt explains this in detail. with this video. starts getting to the point around 10 mins but the whole thing is good and specifically talks about ground rods at generators at satellite dishes at 15:30
https://www.youtube.com/watch?v=YuDqXFvRv94

 

[JackMS]

I cleaned s8 and everything else I could get to. The percent load meter started working and I ran 3 ac's and the microwave. Only showed about 40 percent load or a little higher. About right because clamp on meter showed 29 amps on one leg and 18 on the other. Then i ran a 3 phase ac on it. Worked good there also. It's coming along.

 

[Guyfang]

Dude, you're smoking! One step at a time.

 

[m32825]

>Nasa has tall lightning rods around
>the launch pad to protect from lightning
>strikes not a ground rod attached to the
>bottom of the launch pad.

A while back I saw a story about NASA's early attempts to detect the location of strikes so that they could do detailed checks of equipment in a certain building if a strike was close by. They had this prototype detector on a tripod with an antenna and they were trying to collect some data with it. One of the engineers took it home with him and set it up in the yard while he ate lunch. Lightning made a direct strike on the detector. It was kind of expensive, but they knew EXACTLY where that one hit! I would love to have heard the good/bad news call to the boss afterwards...

 

[novaman]

>Nasa has tall lightning rods around
>the launch pad to protect from lightning
>strikes not a ground rod attached to the
>bottom of the launch pad.

A while back I saw a story about NASA's early attempts to detect the location of strikes so that they could do detailed checks of equipment in a certain building if a strike was close by. They had this prototype detector on a tripod with an antenna and they were trying to collect some data with it. One of the engineers took it home with him and set it up in the yard while he ate lunch. Lightning made a direct strike on the detector. It was kind of expensive, but they knew EXACTLY where that one hit! I would love to have heard the good/bad news call to the boss afterwards...

Works great boss! it said it hit at 0° due center