Using the truck bed 240v outlet to power an RV

[chl]

also, here's a conundrum I just experienced:

While my LIGHTNING's ProPowerOnboard worked easily and perfectly for my last camper, a typical 30amp 120v model, my new camper causes the truck to 'detect' a possible GROUND FAULT and shuts it off. Strange. But, probably not uncommon, as the WIRING for certain GFCI outlet circuits can 'fight' with the truck's own GFCI internal Ground Fault detection.

So, in the end, no matter how I tried to provide power to the camper, whether thru the 30amp 240v Twist-Lock with an adapter, or via one of the bed 20amp 120v outlets, the system just would NOT accept the power, and would fault... EXCEPT when I completely REMOVED the GFCI circuit from the camper's main panel, including the ground AND the neutral wires, after shutting off the breaker.

The GFCI circuit was causing the Ground Fault interruption.
Interestingly, this single GFCI circuit provides power for ALL of the camper's outlets, both inside and out, with the main outlet RESET unit being in the bathroom.

Although replacing the GFCI outlet with a standard outlet is the answer to allow ProPower to work, I suspect the RV industry would frown on such modifications. This is not an uncommon problem, though, as trying to use my home's exterior GFCI outlet to power the camper was also defeated when the home's GFCI outlet tripped. Using one of my home's 'regular' outlets worked just FINE.
GFCI outlets tend to 'fight' each other, at times. It could be the outlet, or it's internal wiring, or it may just be the wiring scheme within the camper's own Main Breaker panel, too.

Hard to know. and aggravating.

There must be a grounded neutral in the camper causing the problem.

A transfer switch that switches the neutral and hots would solve it like the Generac 6853 for example, about $400 on Amazon.

From the manual page 183:
---
Grounding Type Neutral Bonded

The neutral of the inverter generator is bonded to system ground.
Connecting loads that also have neutral bonded to ground causes the ground fault detection
to trip.

Note: If additional grounding measures are required, consult with a qualified electrician.
---
With two paths to ground on the neutrals, the GFCI trips. The solution is a transfer switch that eliminates the double grounding of the neutral.

From a generator manufacturer's web site I think:

---
If the current flowing through two circuit conductors differs by a very small amount, the GFCI instantly interrupts the current flow to prevent a lethal amount of electricity from reaching the consumer. The consumer may feel a painful shock, but will not be electrocuted.

With ground and neutral bonded, current can travel on both ground and neutral back to the main panel. If the load becomes unbalanced and ground and neutral are bonded, the current will flow through anything bonded to the sub-panel (enclosure, ground wire, piping, etc.) and back to the main panel. Obvious shock hazard!

---
For separately derived systems, manufacturers also offer transfer switches that switch the neutral conductor together with the phase conductors. Using a switched neutral isolates the ground conductor of the unconnected power source to avoid ground current pathway problems. Again, a switched neutral is shown in Figure 1.

----
It's a common problem for generators with grounded neutrals (bonded neutrals) and the Lightning pro power output is a generator (see manual page 183 reference above).

Sponsored

 

[hturnerfamily]

Has anyone tried to run the the air conditioning in the trailer[camper] with Lightning power while driving down the road?

yes, it works fine.

but, there are also some details to note:

A) the air conditioner's Amperage will play heavily into your success, as roof a/c units that are typical of campers are 13.5k, and some are larger 15k units... meaning you'll have a large 'start up' power spike, although they are both typically on 20amp breakers, resting in the 12-15 amp range while running.

B) 'How' you mange to get the power to the camper will differ, also, as some will try to run their camper's 30amp shore cord directly to the truck, while others of us will use an extension cord, with an adapter, from one of the truck's 20amp outlets. You'll need flexibility between the camper and the truck, over the hitch, if using the ProPower while under tow...

C) the EXTENSION CORD you will use will need to be able to handle this larger amperage, such as a heavy-duty construction-grade 20amp type.

D) ProPower can handle the power, but the GFCI within the camper, and the truck's Bonded Neutral, can cause issues with nuisance 'Ground Fault Interruption' tripping.

I've just experienced my newer camper's internal wiring interfering with the truck's ProPower output... if I use my home's GFCI external outlet, the camper trips the GFCI. If I use the truck, the camper trips the truck's GFCI. But, if I plug the camper into a 'regular' outlet, it works just fine. This may have to do more with the camper's 'Bonded Neutral' screw within it's Breaker panel, rather than the camper's own GFCI circuit, but it's hard to tell without a LOT of investigation.
It's certainly known well in the RVing community that even trying to use a campground's 20amp GFCI outlet will many times not work, as the camper's own GFCI circuit, itself, causes issues, or 'fights' with the other GFCI external outlet.

Most of the time we have our camper in tow, it is provided power from the bed, to run fans, keep the converter charging the battery(s), and the 120v fridge cooling(the main reason)...
but, most of the time we've also used the roof air conditioner was when PARKED, leaving the truck on, while near the beach, or overnight between destinations, etc.
We have to MANAGE power usage, though, when the a/c is in play, as trying to use the microwave WHILE the a/c compressor is running would likely not play well with the extension cord's max amperage. Turning off the a/c compressor for a few minutes is not really an issue, though.

 

[hturnerfamily]

There must be a grounded neutral in the camper causing the problem.

likely true... I'm investigating the issue, both with my home's external GFCI outlet, AND the truck's outlets... and, have arrived at a similar feeling that this may be exactly what the GFCI external outlet and the truck are fighting with...

will check back tomorrow with an update... the RV Breaker Panel manafacturer, WFCO, doesn't go into any details about any 'bonding' screw within their units, but I see one in the middle of the Neutral bar that makes me think that it is there... it is unlike the other neutral screws, as they are 'allen wrench' type screws, whereas this one is phillips, and is a different color.

 

[chl]

there's no reason not to charge your Lightning from your RV's own 120v exterior outlet if you are going to go thru the motions of trying to adapter your EVSE to a 120v 30amp campground outlet - the results are the same: 8-12 amps, at most, of 120v charging, which will take forever, but is feasible if that's what you wish.

In my camping experience, I would use the 50 amp 240v outlet for the LIGHTNING, and use an adapter for the RV to the 30amp 120v outlet, as the RV uses MUCH LESS power than the LIGHTNING, for sure... most ANY camper or RV can survive very easily on 'only' 30 amps, and most campgrounds ONLY have 30 amps.

True, you CAN use a dogbone adapter on the 30A 120v campground outlet

there's no reason not to charge your Lightning from your RV's own 120v exterior outlet if you are going to go thru the motions of trying to adapter your EVSE to a 120v 30amp campground outlet - the results are the same: 8-12 amps, at most, of 120v charging, which will take forever, but is feasible if that's what you wish.

In my camping experience, I would use the 50 amp 240v outlet for the LIGHTNING, and use an adapter for the RV to the 30amp 120v outlet, as the RV uses MUCH LESS power than the LIGHTNING, for sure... most ANY camper or RV can survive very easily on 'only' 30 amps, and most campgrounds ONLY have 30 amps.

Yes, you CAN plug a 50A trailer/camper into a 30A campground out let IF:

1) you don't have any 240v requirements inside the camper/RV and

2) you won't exceed the 30A limit, i.e., you don;t need the full 50A of the other outlet

This is what the wiring is (att-30 plug at top to 14-50 receptacle at the bottom).
As you can see, you only 120v not 240v.

See: https://www.rvtravel.com/hooking-up-50-amp-trailer-to-30-amp-service-at-campground/

 

[chl]

likely true... I'm investigating the issue, both with my home's external GFCI outlet, AND the truck's outlets... and, have arrived at a similar feeling that this may be exactly what the GFCI external outlet and the truck are fighting with...

will check back tomorrow with an update... the RV Breaker Panel manafacturer, WFCO, doesn't go into any details about any 'bonding' screw within their units, but I see one in the middle of the Neutral bar that makes me think that it is there... it is unlike the other neutral screws, as they are 'allen wrench' type screws, whereas this one is phillips, and is a different color.

You might see two bus bars/terminal bars, one for ground wires (usually green or bare) and one for neutrals (usually white) and a metal piece that connects the neutral bus to the frame of the panel. That is the bonding piece.

If you are going to unbond the panel neutrals, ONLY do that BEFORE you will be powering it by the Lightning or other bonded generator. Do not do it, bond or unbond the neutral bar, while the panel is powered - risk of accidental shock.

If inside the panel the white (neutral) wires and the green/bare (ground) wires are connected to the same bus bar/terminal bar, then you will have to rewire it so they are on separate bars, and then unbond the bar with the whites - usually only one bus/terminal bar can be unbonded.

Definitely seek guidance from the manufacturer and/or a licensed electrician.

Here is an image of an panel before wiring or breakers have been put in showing a typicaal split phase arrangement:

The next pic shows the neutral bus bonding jumper - you'd have to remove that to unbond the neutrals in the panel, the put it back to bond the neutrals in the panel.

Some times, it may not be possible to unbond the neutrals. In that case, the solution is a transfer switch as mentioned before.

 

[chl]

PS:

You would never UNBOND your home main service panel! The above main service panel is only for illustration. Just like you should never unbond the Lightning ProPower generator output receptacle neutrals.

You should however unbond the neutrals permanently a sub-panel to which the main panel is wired in an unattached building for example, per the NEC.

Your RV panel may not be wired as neatly as the above, alas. So getting to the neutral bonding jumper could be difficult, it may be obscured/blocked by wires.

You want to put a warning somewhere on the panel that is has been unbonded when you do that.

Bonding and unbonding the panel could become tiresome.

 

[hturnerfamily]

RV Breaker Panels don't look like the typical home panel, so your photos don't really go into the same detail RV owners would want to see...but, yes, there are TWO bonding bars: Grounds, and Neutrals, which are separated.
Factories typically wire these like a 'home' panel would be - with separate Grounds and Neutrals on separate bars, as though it is the 'Primary' shut-off panel, like your home's...
BUT, when you think about it, RVs are mobile, and can use either Utility power, such as at a campground or home, OR they can use a generator source...

so, the question then begs: does the typical RV camper panel need to be Neutral-bonded, or not... and, does the answer depend on the SOURCE or power, and whether IT is already neutral-bonded?
Since then these RV camper panels would be considered 'sub-panels' when on Utility power thru an already bonded main panel, the separated Grounds and Neutrals would already be correct... the only question is about the Neutral bonding within the RV camper.

Now, for background - I've had several campers, all similar, and all with the same 'type' of RV Breaker Panel, but possibly from different manufacturers. The prior two campers had no problem with my truck's ProPower, even running everything including the roof air conditioner. This 'new' camper, though, is giving me fits.

FIRST: plugging into my home's GFCI exterior outlet is a problem. Nuisance tripping either when I plug in, or if it DOES stay powered after several tries, it immediately trips if I try to use either the microwave, or the roof air conditioner.
SECOND: plugging into my truck's ProPower typically causes a 'Ground Fault Interruption' and shuts it down. On several occasions I've been able to get the truck to stay powered, but AFTER I removed the camper's own GFCI outlet from the breaker panel wiring, thinking that this was causing the fault.
THIRD: I not only removed the camper's own GFCI outlet, but replaced it with a standard outlet, which then allowed the truck's ProPower to provide constant power. Unfortunately, though, and again, trying to use the microwave or the roof air conditioner immediately caused the same 'Ground Fault Interruption' from the truck.
FOURTH: I also then removed the Neutral-bonding screws from the camper's breaker panel. This, though, made no difference in the actions between the camper and the truck. Sad.

So, it feels like I can get power from the truck to the camper, yes, but only on a minimal basis - meaning powering the camper's breaker panel, for outlets and the battery converter, but that's about it. It seems that if I try to power anything with a grounded plug, I lose power. I have plenty of amperage headroom, so it's not a situation of tripping because of power, but tripping because of a Ground Fault.


My next try is going to be similar to providing ProPower to my home: remove the ground from the cord between the truck and the camper. If this resolves the home's issue with a bonded-neutral at the main panel, it seems to make sense that it might work the same for the camper's bonded-neutral panel.

 

[hturnerfamily]

SOLVED:

A) REMOVED the GROUND wire from the extension cord between the truck's 120v bed outlet and the camper's shore cord.

B) I had also previously REMOVED the GFCI outlet/circuit from the camper, replaced with a standard outlet. This had been done to allow the testing of ProPower, or the home's external GFCI outlet, not to 'fight' the camper's own GFCI wiring... a known problem with many owners in the RVing/camping world.

C) the 'bonded' Neutral in the camper's breaker panel remains in place. No change.

This SUCCESS allowed not only the 'basic' electrical power to the outlets, but ALSO to run the microwave and roof air conditioner(15k), successfully, from the truck's ProPower. The pull from the a/c unit while running was about 1,200 watts, maybe 10 amps or so, with a few fans, and the battery converter, also. This was all with 120v power from one of the bed outlets.

I will ultimately also try this with the 240v 30amp outlet in the truck's bed, but for now, with both the microwave AND the a/c unit running successfully from the bed's 120v outlet, it seems like this is not really any urgent need.
While we've tested the output of the truck bed's outlets at all being up to 30 amps, too, using the 240v outlet for a 120v camper probably is unwarranted.

Now, removing the Ground from the wiring between the truck and the camper might seem unsafe, or dangerous, but let's go back a few years when even the standard HOME, itself, did not have outlets with Grounds.
We all know that this was added later to provide a better level of safety, yes, but it's not inherently 'dangerous', any more than your 'older' electric dryer in your home that also does not have a GROUND(three wire type).
The electrical industry has now added them to newer home's wiring schemes, of course, but older homes still use ungrounded dryers everyday, and ungrounded outlets, and can continue to do so.

This 'ungrounded' power usage to the camper is also relatively infrequent. It is only when needed while traveling, under tow, and also periodically if needed while parked, with no utility power source available.


so, in the end, it seems similar to providing 'whole house' power between the truck's 240v outlet and the home's main neutral-bonded panel: the GROUND is what is causing the 'Ground Fault Interruption' tripping of the truck. Without the ground wire, everything works perfectly, in both situations.

Sponsored