Let's Get Grounded!

Dutch061

I suspect that the fused ground is because in EU they would run this on 220 VAC which would mean 2 x 110 VAC coming in. If this is true, part of what should be done when it is converted to 110 VAC is this fuse should be replaced with a jumper. USA Code doesn't allow fusing on the negative wire or a ground circuit.

Brad

ScottG

The fused "ground" in question is the negative leg of the Alde's 12VDC power supply from the converter/battery. I don't believe that differs between north America and Europe.

That said, I'm not entirely sure how the two power supplies interconnect inside the unit, so the weird fuse on the negative leg remains a bit of a mystery and may very well relate to some adaptation from the European power supply. It's certainly curious that some degree of DC grounding appears to occur through the ground pin on the 120VAC side (see my post of August 3) but admittedly the ability to make sense of all this is getting above my pay grade.

It's also curious that Alde eliminated the 12VDC- fusing in the newer 3020 models. I wonder if they have done the same thing in Europe.  

jkjenn

My 2015 never had a blown Alde fuse. I always attributed that (perhaps in error) to my Progressove EMS.

ScottG

The Alde in my 2015 has never blown a fuse, and I have no EMS. Admittedly, I probably run my Alde much less than you (@jkjenn) did--and even less frequently on shore power. It did seem like an issue that affected some units repeatedly and others not at all.

Whether the fuse-blowing problem in any way related to the issue of bonding (a.k.a. "grounding") the 12VDC system to the chassis remains anyone's guess. It's rapidly becoming a moot point since the newer 3020 units have no fuse on the 12VDC negative leg.   

ChanW

And.... I blew the Alde fuses a number of times, and I also have the Progressive EMS... 😏
I believe haven't blown them in the time since I replaced them with the slow-blow version.

Dutch061

As I have battled through the voltage drop testing and further research, I came a across a pretty handy App for my phone called Electrical Calculations. With this App, you can create scenarios to see projected outcomes based on gauge of wire, length of run, temperature, voltage, and amperage draw.

For those nerds (myself included) that really want to have a better understanding of the Power loss that occurs, I have run several different scenarios based on 12 VDC, either a 10 Amp or 40 Amp draw, and either 22 feet (estimated length of ground wire in our 2020 400 BDL) or 50 feet (estimated length of ground and power feed wires combined). 

Please find that document attached for reference or a headache. I have also posted this in the Corrosion thread.

Brad

MuttonChops

Well, Well I Found my Trailer's Chassis Ground
and it is Open/floating

In an earlier post to this thread I noted my 2018 March-2018 Build 320S did not have a chassis ground placed near the Junction Box as several owners reported.

Today I had need to remove part of the Air-Flow-Belly-Pan and found the Chassis Ground location.
     Drivers side of inside frame,
     aft of the wheel well,
     in the general area of the Power Center and ground bus.

Now my trailer has 35+K towing miles that includes several hundred miles of county gravel roads, a hundred or so miles of dirt (BLM, NFS) roads, and at least three winter snow storm days of wet/salty highway driving.

End result is the Screw Head has failed and the electrical contact post is not looking so great.
I'm thinking an occasional inspection should be added to my routine

BrianZ

Wow, @MuttonChops, that's an important finding!  Is this the A/C bare wire ground that goes into the floor in that area?  I guess you'll try to grip the remains of that screw & try to back it out & replace?  Or else maybe drill a new hole for a new screw.  Also wondering whether we still should have a DC ground on the chasis up front near the J-box.  I guess that ground block is aluminum?

MuttonChops

BrianZ said:

Wow, @MuttonChops, that's an important finding!  Is this the A/C bare wire ground that goes into the floor in that area?  I guess you'll try to grip the remains of that screw & try to back it out & replace?  Or else maybe drill a new hole for a new screw.  Also wondering whether we still should have a DC ground on the chassis up front near the J-box.  I guess that ground block is aluminum?

All good questions . . . afraid all I can say are opinions/guesses.
I've not investigated the routing/connection of this wire - - other projects have my time.

The last time I did any measurements; my DC Ground Bus was directly connected to chassis.
   While how/where was not clear.

Before I fix this connection - - will recheck the DC ground bus - - do expect your idea that this 'floating ground' wire goes to the AC Side of the Power Center is accurate.

Meanwhile, everything works. My "is the frame 'Hot' tester" says no and the Alde is running just fine in our teen's F nights.  So guess I'm ignoring what this open ground could mean . . . . .

Denny16

I would replace the aluminum ground block with brass, bronze or better yet, stainless steel.
 Cheers 

ScottG

@MuttonChops, it's been a while since I've pondered this issue, but I think--as @BrianZ suggested--that is the chassis ground for the 120VAC side of the electrical system. It ensures that the trailer chassis is properly grounded when plugged into shore power, but probably has little effect on the 12VDC side which (by one means or another, depending on model year) seems to have it's own chassis ground.

Bayliss

@MuttonChops, I too believe it is what nuCamp has referred to in the past as the "main" ground to the chassis (see my July 2021 post in this discussion thread.)  In reality, it is, as @ScottG noted, the 120VAC ground.  It appears that the solid copper wire that originates in the power center/converter is connected to the metal lug in your photos.  Interesting find.  Nice to see what it looks like, which is similar to the lug next to the junction box at the front of my trailer (and other trailers, as noted by a few owners on this forum.)  Thanks for posting the info and photos.

KK1L

The poor DC ground situation is exactly the reason for having a fuse on the negative side leg of circuit at the battery/inverter. If 12V chassis ground fails, then the ground could be completed through the components attached to the 12V circuit which could damage them.