14-50R Outlet Neutral Bonding

[mongo]

A possible solution is to not connect the ground between the truck and the panel, this would prevent the split current. What sort of danger would this cause? Given that the neutral and ground is still connected at the home panel, a fault in the branch circuit would still flow through the ground back to neutral and trip the branch breaker. A fault at the truck side would still short the shell to ground to neutral through the truck's bond and trip whatever breaker there is. Is that a solution?

That would be worse since the truck would still be sitting at the local neutral potential, but there is only one return path from truck to house so higher resistance and higher voltage.

Removing the neutral connection and putting a 120/240 auto transformer at the house would address the issue. Oh right, that is how Powershare does it, so maybe neutral-ground is always there since the NACS port has no neutral?

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[MeadowShade]

I have not read all of these posts because I would NOT understand IF I did. BUT ... here is what I know.

I tried to hook up the mobile charger to a 30amp RV cord that was connected through a 30 to 50 amp adapter that would plug into a 50 plug for an electric stove. It did NOT work!

Trying to get an answer was nearly impossible but finally, on an RV YouTube, that was discussing charging at camp grounds, they pointed out that there is a special (magic) adapter that is need for charging from a 30amp cord. It is marked for EV Charging and I ordered one from Amazon. Magic! It works!

All I know is it has something to do with the Neutral and the ground. I have installed 3 wall charger and the plug points for 2 more mobile chargers and all have worked just fine. The adapter also works at campgrounds.

As I recall, in the breaker boxes, I hooked the Neutral and the ground on the same buss and the other two went to separate power bars.

 

[mongo]

I have not read all of these posts because I would NOT understand IF I did. BUT ... here is what I know.

I tried to hook up the mobile charger to a 30amp RV cord that was connected through a 30 to 50 amp adapter that would plug into a 50 plug for an electric stove. It did NOT work!

Trying to get an answer was nearly impossible but finally, on an RV YouTube, that was discussing charging at camp grounds, they pointed out that there is a special (magic) adapter that is need for charging from a 30amp cord. It is marked for EV Charging and I ordered one from Amazon. Magic! It works!

All I know is it has something to do with the Neutral and the ground. I have installed 3 wall charger and the plug points for 2 more mobile chargers and all have worked just fine. The adapter also works at campgrounds.

As I recall, in the breaker boxes, I hooked the Neutral and the ground on the same buss and the other two went to separate power bars.

30A travel trailer is 30A @ 120V, hot, neutral, ground
50A stove is 50A @ 240V withtwo phases of hot and may lack a neutral (or ground depending on age).

 

[cybercricket]

Mobile charger definitely checks for grounding, and when the ground isn't present connecting Ground to Neutral will work.

 

[znowstorm]

I was looking at various options when connecting a generator (e.g. Cybertruck, F150 Lighting) with internal Neutral to Ground bond to a home panel that also has neutral to ground bond. This is assuming we cannot break the bond easily on either side (physically or with a neutral breaking transfer switch)

Now, none of these are code compliant, but are meant as "safe-ish" option for temporary use

Option 1 - Connect all wires as normal - Preferred if generator outlet is not GFCI
Accept that returning current from home circuits will split and return to generator via both the ground and neutral wire between home panel and generator. If we use 30 feet of 8/3 wire, a low voltage of up to 0.25V can be induced on ground in home side due to ground wire current voltage drop. As long as that ground wire path is good for the max 20A current. This isn't a bid deal.
Fault between HOT and Chassis would still work and trip breakers
Generator's outlet must not be GCFI protected or it would immediately trip

Option 2 - Do not connect ground wire between generator and home panel - Only option if generator is GFCI protected
Leave the ground wire not connected. No current split as ground is missing.
Fault (HOT to Chassis) on home and generator would still return via their respective ground to neutral bond and trip breakers, which is good.
Generator outlet should have GFCI to prevent shock danger if the neutral line connecting home and generator is broken. Unlikely, but high serious when it occurs.
Generator should not be grounded as it would create unpredictable ground current loop as returning current split at the home panel neutral to ground bond and return to generator from non-wire ground path
Generator frame/ground can float at a non 0 voltage compared to home ground. Measure to make sure it isn't too high <20V first

https://docs.google.com/presentatio...B7hl5sBWe1ss/edit#slide=id.g333a6ac57bf_0_197

 

[habendanio]

I know that the mobile charger works from the 240v outlet in the bed so I am sure that the neutral is definitely bonded to the ground, otherwise the charger would have an error when used to charge other ev’s from the cybertruck.

 

[cybercricket]

I know that the mobile charger works from the 240v outlet in the bed so I am sure that the neutral is definitely bonded to the ground, otherwise the charger would have an error when used to charge other ev’s from the cybertruck.

That only proves it will bond the neutral when such bonding isn't already present. A good test would be as follows :

- Connect neutral to ground on the 14-50
- Enable the 14-50 output
- Remove the neutral to ground jumper while the output is enabled
- Measure the voltage between the ground and any of the hot legs

If there is voltage, then there is no sensing and it just bonds the two unconditionally. If there is no voltage, then it does it automatically only when needed.

 

[znowstorm]

Is it possible (or probable) that it would be smart enough to close a relay and bond neutral to ground when it sense that it isn't already bonded? That would be an interesting case but I find it hard to believe it would be built that way. If that is the case, then it would be nearly impossible to tell, as no matter how you measure it, it would be bonded. If it is not bonded, then it would bond it self. If it is bonded on the other side, it won't bond it self, but when you measure it, it would still be bonded from the other side. Then if you remove the other bond, it would bond itself.

One way to measure is to plug this into a home panel that already has a ground neutral bond (most would). Run some current through it, and use a current meter to measure whether there is any current in the ground wire. Some current would flow on the ground wire (assume the load is not perfectly balanced) if the Cybertruck's neutral/ground is internally bonded.

Can we just ask Tesla?

In any case. If we don't know that it is bonded or not. As long as the outlet is not GFCI protected, the best thing to do is to connect all wires and accept ground current flow between the Tesla and the home panel. Just double check the neutral to ground path on your home panel to make sure it is good enough to handle the max 20A sustained current.

 

[cybercricket]

Is it possible (or probable) that it would be smart enough to close a relay and bond neutral to ground when it sense that it isn't already bonded? That would be an interesting case but I find it hard to believe it would be built that way. If that is the case, then it would be nearly impossible to tell, as no matter how you measure it, it would be bonded. If it is not bonded, then it would bond it self. If it is bonded on the other side, it won't bond it self, but when you measure it, it would still be bonded from the other side. Then if you remove the other bond, it would bond itself.

Would Tesla go through the trouble of adding an extra part (relay) to bond Neutral to Ground instead of just jumping the two pins permanently if they didn' t mean to control it dynamically ?

The above test process I proposed makes the assumption the logic to bond or not to bond is executed once on "output enable." Naturally if it's monitoring the state of the ground continuously it will be significantly more difficult to figure out what it is doing.

Can we just ask Tesla?

Good luck.

 

[znowstorm]

My money is that it is just permanently bonded with a soldered wire...

But what you are saying is that before it first activates, it is not bonded in the Tesla. But on activation, it is going to try to increase the voltage on the neutral, and if it can, it means it is not bonded on the other side and it would then close a rely to bond it within the Tesla. Otherwise, it would leave it open. It would then activate the outlet. That would be an interesting case, and the test you suggest would work. I just don't think they would build all that complexity and logic into it.

 

[mongo]

My money is that it is just permanently bonded with a soldered wire...

I can say that is most definitely not the case.

 

[cybercricket]

I can say that is most definitely not the case.

Exactly. I remember you already pointed that out earlier, which is what backs my suspicion there is logic built-in there for a reason, otherwise they'd just not have an extra part in the system and save $2.

 

[Swamibob]

I was also thinking about using a generator transfer switch and inlet to power their house using the 14-50r in the bed. I plan on using an SSR-50r STW inlet and I have read the same thing you are talking about.

• • Ground-Neutral Bond Conflict: This is a major technical hurdle. Because the truck's 240V outlet likely has an internal neutral-to-ground bond when active, connecting it to a home panel (which also has a bond) creates a "dual bond". This frequently causes the truck's built-in GFCI to trip immediately.
  • Neutral-Switching Transfer Switches: To solve the GFCI tripping issue, some owners recommend using a neutral-switching transfer switch (like certain GenerLink models or specialized manual switches) rather than a simple interlock kit. This completely isolates the truck's neutral-ground bond from the house's bond.

Have you found out if this is true or not? If so, how did you fix it, if you did? Did you try not connecting the ground and did it work? Or did it just work as is hooking it up normally? You and me can't be the only people trying to just plug it in like a generator. Please give me an update.

Update: this guy just jacked it into his 14-50r and it didn't seem like there was a bonding issue and i'm sure his box is neutral -ground bond. right? here is the link

 

[Floridaman]

I was also thinking about using a generator transfer switch and inlet to power their house using the 14-50r in the bed. I plan on using an SSR-50r STW inlet and I have read the same thing you are talking about.

• • Ground-Neutral Bond Conflict: This is a major technical hurdle. Because the truck's 240V outlet likely has an internal neutral-to-ground bond when active, connecting it to a home panel (which also has a bond) creates a "dual bond". This frequently causes the truck's built-in GFCI to trip immediately.
  • Neutral-Switching Transfer Switches: To solve the GFCI tripping issue, some owners recommend using a neutral-switching transfer switch (like certain GenerLink models or specialized manual switches) rather than a simple interlock kit. This completely isolates the truck's neutral-ground bond from the house's bond.

Have you found out if this is true or not? If so, how did you fix it, if you did? Did you try not connecting the ground and did it work? Or did it just work as is hooking it up normally? You and me can't be the only people trying to just plug it in like a generator. Please give me an update.

Update: this guy just jacked it into his 14-50r and it didn't seem like there was a bonding issue and i'm sure his box is neutral -ground bond. right? here is the link

Hey, Bob!

I also used the 14-50 solution to backfeed my house when the power was out in the hurricane last year. It worked like a champ with no additional steps required..

Good luck!

 

[Swamibob]

Hey, Bob!

I also used the 14-50 solution to backfeed my house when the power was out in the hurricane last year. It worked like a champ with no additional steps required..

Good luck!

Thanks Floridaman, I see you're in Tampa, I'm in Lakeland so that makes us Cybertruck neighbors! I'm going to give it a shot myself and see if it works for me.

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