Transfer Switch

[Danface]

This is a wild overreaction not based on reality. There is nothing to get anyone killed, and nothing to start a fire. If you're going to make such outrageous claims, back it up with factual examples or data. And not some completely absurd edge case that would burn the house down with or without the hookup.

There are lots of things that are in the name of safely doing what needs to be done in an emergency. This is one of them.


Circuit breakers in the panel will continue to operate just as they always have before. NOTHING about this changes the existing breaker's ability to function properly. This includes normal overload, GFCI, and AFCI type breakers. Fault current will get back to the source over the hot and neutral legs from the panel to the truck, just like it does when going back to the source on the utility pole outside the house. There isn't a separate grounding conductor going out to the transformer either. So to claim this is starting fires is non-sense.

By leaving the ground intact through the generator cable up to the female plug, you're protecting the cable itself from ground faults. Like if you run it over with a lawn mower or it gets water into it. The truck (or generator) overload and GFCI will handle it because it's bonded at the truck.

There is NOTHING to start a fire and NOTHING is unprotected. The only thing that is unprotected, is the page of the code book that says the bond needs to be at the first disconnect, which technically is the truck's built in circuit breaker. The end.

Cite code all you want if you're that much in love with it. I get it. We all get it. It's not the perfect code compliant method. We all get that a transfer switch is better. We all get it. And we're all still going to do what is safe, practical, prudent, and temporary in an emergency.

Meanwhile, there's millions of occupied and approved homes with knob and tube wiring or ungrounded outlets and no AFCIs and no GFCIs all across America that are actual fire risk that kill people. I'll worry about this safe and practical temporary emergency hookup when someone starts worry about actual dangers first.

Agree ... but to that point, I know here that that isurance company increases the rate when a house has knob and tube. We used to ride in cars without seat belts (the auto companies fought for years for that .... I mean it was going to add $50 more to the car), rode bikes without helmets etc etc. Let's not forget the single most important thing of our current times in the US of A, lawsuits.

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[Henry Ford]

There is NOTHING to start a fire and NOTHING is unprotected. The only thing that is unprotected, is the page of the code book that says the bond needs to be at the first disconnect, which technically is the truck's built in circuit breaker. The end.

Your method bypasses the GFCI protection the truck provides. You might be fine with that but it should be mentioned when you are giving advice online

Cite code all you want if you're that much in love with it. I get it. We all get it. It's not the perfect code compliant method. We all get that a transfer switch is better. We all get it. And we're all still going to do what is safe, practical, prudent, and temporary in an emergency.

Not everyone is going to do what is safe, practical, prudent, and temporary. Some people are going to do what's easy and cheap. And they might cut corners. And what they do might be safe as long as they install it like you described. But two or three or ten years from now their memory might be a little fuzzy or maybe they aren't living in the same home anymore and someone else screws it up. Then it's unsafe, impractical, imprudent, and permanent.

 

[Runaway Tractor]

Your method bypasses the GFCI protection the truck provides. You might be fine with that but it should be mentioned when you are giving advice online

There is no GFCI protection on the main breaker or the utility pole outside either. And virtually all portable generators also don't have a GFCI on the 240v outlet. You haven't given up a safety feature that existed every other day of the week when it comes to powering a house.

I cannot even imagine the amount of nuisance tripping that would occur with main power on a very sensitive GFCI. Which would just encourage people to bypass grounds at the devices which is actually dangerous...

Not everyone is going to do what is safe, practical, prudent, and temporary. Some people are going to do what's easy and cheap. And they might cut corners. And what they do might be safe as long as they install it like you described.

Yep. If someone does something else completely different, that's not on me and has nothing to do with the method I'm suggesting . The same could be said about the code compliant sub panel method, which can also be done totally wrong and dangerous. Which would totally not be your fault either. I've seen some horrifying sub panels that make you wonder how it hasn't burned down yet for real.

But two or three or ten years from now their memory might be a little fuzzy or maybe they aren't living in the same home anymore and someone else screws it up. Then it's unsafe, impractical, imprudent, and permanent.

This is very valid. This is why I suggested labeling the snot out of the cable and using it only for the V2H. That said, I think in the future I should elaborate that the cable cannot be used for other things like powering tools at a job site.

I was going to put a box on the end of the cable just before the female end with a safety covered toggle switch that disables the ground for that reason. Makes it much less likely for someone to make that mistake. But ultimately decided to put hat switch on the generator inlet when I redo it all this summer. That way the cable can be fully intact end to end.

 

[Henry Ford]

There is no GFCI protection on the main breaker or the utility pole outside either. And virtually all portable generators also don't have a GFCI on the 240v outlet. You haven't given up a safety feature that existed every other day of the week when it comes to powering a house.

I cannot even imagine the amount of nuisance tripping that would occur with main power on a very sensitive GFCI. Which would just encourage people to bypass grounds at the devices which is actually dangerous...

You said nothing is unprotected, I pointed out what is unprotected.

Yep. If someone does something else completely different, that's not on me and has nothing to do with the method I'm suggesting . The same could be said about the code compliant sub panel method, which can also be done totally wrong and dangerous. Which would totally not be your fault either. I've seen some horrifying sub panels that make you wonder how it hasn't burned down yet for real.

One method could pass an inspection, the other can't.

This is very valid. This is why I suggested labeling the snot out of the cable and using it only for the V2H. That said, I think in the future I should elaborate that the cable cannot be used for other things like powering tools at a job site.

I was going to put a box on the end of the cable just before the female end with a safety covered toggle switch that disables the ground for that reason. Makes it much less likely for someone to make that mistake. But ultimately decided to put hat switch on the generator inlet when I redo it all this summer. That way the cable can be fully intact end to end.

This is the problem. Any future user of the "pull the ground" method has to know what the installer was thinking. The code is written so the thoughts of the installer are taken out of the equation.

I've told this story before but I'll tell it again. My father installed a DIY generator inlet that was wildly non-code compliant. Then he died and took his knowledge of it with him. He left behind some notes in the panel but there is one person left on earth who knows what he was thinking and it isn't my mother, who is the person who needs to know how to use it. If I don't get around to fixing it before I'm gone it's someone else's problem. Had my father done it right from the beginning there would be no issue.

 

[Runaway Tractor]

You said nothing is unprotected, I pointed out what is unprotected.

It's not unprotected it is just as protected as it was 30 seconds ago on main power if not more. It was never GFCI protected before and it still won't be now. You could say it isn't adding a whole new and unnecessary level of protection that no home on the planet has either?

One method could pass an inspection, the other can't.

What inspection? When does the county come inspect a homeowner's extension cord??

This is the problem. Any future user of the "pull the ground" method has to know what the installer was thinking. The code is written so the thoughts of the installer are taken out of the equation.

My generator inlet and interlock are code compliant and UL listed.

I've told this story before but I'll tell it again. My father installed a DIY generator inlet that was wildly non-code compliant. Then he died and took his knowledge of it with him. He left behind some notes in the panel but there is one person left on earth who knows what he was thinking and it isn't my mother, who is the person who needs to know how to use it. If I don't get around to fixing it before I'm gone it's someone else's problem. Had my father done it right from the beginning there would be no issue.

So your father installed a dangerous non compliant system that has absolutely nothing to do with what we're talking about? If it is so bad, I suggest you do something about it before someone gets hurt instead of posting about it online. Practice what you preach.

 

[Henry Ford]

It's not unprotected it is just as protected as it was 30 seconds ago on main power if not more. It was never GFCI protected before and it still won't be now. You could say it isn't adding a whole new and unnecessary level of protection that no home on the planet has either?

When you take power from a Lightning it has GFCI protection unless you override it. This is worth mentioning when giving electrical advice online.

What inspection?

It a Generac switch were inspected it is possible for it to pass. Pulling the ground from your PIB could not pass inspection. Some people might want the ability to pass an inspection. The ability to pass inspection is a benefit in my estimation.

When does the county come inspect a homeowner's extension cord??

I was going to put a box on the end of the cable just before the female end with a safety covered toggle switch that disables the ground for that reason. Makes it much less likely for someone to make that mistake. But ultimately decided to put hat switch on the generator inlet when I redo it all this summer. That way the cable can be fully intact end to end.

The bolded section doesn't sound like an extension cord to me.

My generator inlet and interlock are code compliant and UL listed.

Maybe today but your plan is not code compliant, unless I'm misunderstanding what that plan is.

So your father installed a dangerous non compliant system that has absolutely nothing to do with what we're talking about? If it is so bad, I suggest you do something about it before someone gets hurt instead of posting about it online. Practice what you preach.

Eventually I'll get around to fixing it but that's not the point. The point is not every idea that works is a good idea. My father's setup is an extremely bad idea and no one should emulate it.

To be clear, I'm an idiot on the internet and no one should take advice from me about anything. Internet ideas should be be scrutinized by actual experts. Loss of property, severe injury, and death are all possibilities when you are messing with electricity.

 

[Runaway Tractor]

Eventually I'll get around to fixing it but that's not the point.

It's the entire point since you are telling everyone else how it should be. When you put your money where your mouth is and fix that horrible dangerous system, I'll stop pointing out the hypocrisy of your comments every time it comes up.

 

[CyclopsThere]

I appreciate both of your comments. Ya'll have some competing viewpoints but I for one am learning lots from both of you. FWIW

It feels like an internet fight to each of you perhaps but IMO it's 2 people with differing informed opinions and priorities. You're both clearly well informed and experienced.

 

[Henry Ford]

It's the entire point since you are telling everyone else how it should be. When you put your money where your mouth is and fix that horrible dangerous system, I'll stop pointing out the hypocrisy of your comments every time it comes up.

I didn't install the horrible dangerous system, my Dad did and he's dead. I'm saying don't do that to your heirs or the future owners of your house. I'm not sure how that is hypocritical.

You are advocating for a code violation. I'm happy to debate the safety merits of pulling the ground on an extension cord or PIB. You seem to think there are none. I disagree.

 

[Runaway Tractor]

The merits, pros, and cons have been discussed. I never said there are no cons, nor do I think that. You've made some good points that I will add to my comments when this comes up in the future, such as the future impacts to other people who don't know about the work arounds. And making clear that the modified cable shouldn't be used for anything else. I will continue to be a reasonable and prudent person when it comes to safely doing what needs to be done in a temporary emergency.

 

[adoublee]

I think my middle ground between @Runaway Tractor and @Henry Ford is that there is some added risk of lifting the ground pin on a generator inlet, but doing it or an iteration of it is probably still best for cost-conscious, reasonably-safe resilience. Here are my own factors:

1. Downstream outlet GFCI's and the truck internal GFCI will de-sensitized when powered from the truck if the ground in the inlet is lifted. This is because a phase wire accidentally touching the metal case of an appliance would not cause current to flow on the ground and back to the source (truck), preventing the GFCI from sensing there is current escaping from the neutral return path. This poses some additional shock hazard, but is how things were in normal conditions before the advent of a ground wire to every outlet/appliance, and then the advent of so many required people-protection (highly sensitive) GFCI's.

2. The truck is power and current limited, much more so than what comes in from the utility. This somewhat mitigates the risk of a phase to neutral fault causing a wire to overheat and create a fire, in comparison to utility source.

3. I want back-up power available to every circuit of my home, where I will manage it's use. Small back-up devices that break the neutral and power a small handful of loads don't offer this.

4. Short of a very major project to route my service conductors through a 4 pole transfer switch sized for the ampacity of my whole home service JUST for the purpose of breaking/disconnecting neutral to ground bond, I know of no other solution for addressing the technical issue other than a change to the truck's inverters which isn't happening. Lifting the permanently installed neutral to ground bond during emergency use feels like a much higher risk long term as reconnection might not be made well for normal operation.

Therefore, I do feel having the ground lifted on the inlet is probably the most reasonable solution for emergency back-up circumstances. Ways that I might mitigate risk would be to:

1. Install a labelled toggle switch beside the inlet to purposefully lift the ground only when required. In an inspection, move, etc this could become a junction box and the switching/lifting capability could be easily removed.

2. Install in a more interior location of garage where someone wouldn't naturally ever connect a "combustion generator" and don't call it a generator inlet. That might be the furthest distance from the garage door, as many people purchase the smallest connection cord they can. Of course there are never guarantees what some other party might do. I'm noting that the 2023 NEC requires small "generators" inlets to be located outdoors now, that the NEC does not define the term generator, and that common definition of generator would be something that converts mechanical energy to electrical energy (NEC text assumes a generator has a "prime mover" for example). I'd suggest the truck be considered a "power supply" and not a generator, noting that an iPhone and a cordless vacuum aren't powered by "generators".

*Nothing here should be considered advice or considered to be evaluated against construction codes.

 

[Runaway Tractor]

All my thoughts exactly except two points below. The safety cover protected switch (think missile launcher arming) to lift the ground pin on the inlet is the "least imperfect" way. In it's normally closed position, the ground is intact with no user intervention needed. You would have to lift a safety cover and flip the switch on purpose to lift the ground pin. Combined with a little sign that says what it does, it's probably the best we can do.

1. Downstream outlet GFCI's and the truck internal GFCI will de-sensitized when powered from the truck if the ground in the inlet is lifted. This is because a phase wire accidentally touching the metal case of an appliance would not cause current to flow on the ground and back to the source (truck), preventing the GFCI from sensing there is current escaping from the neutral return path. This poses some additional shock hazard, but is how things were in normal conditions before the advent of a ground wire to every outlet/appliance, and then the advent of so many required people-protection (highly sensitive) GFCI's.

I think you might be overthinking this one. This would be no different than on normal utility power since there is no GFCI on the main breaker or utility pole. Put another way, any fault of any kind on any branch circuit in the house will behave the same way it would on utility power. Fault current will travel down the branch neutral or branch ground to the panel bond, and the branch circuit breaker will do whatever it is going to do (thermal, overload, gfci, afci, etc).

2. The truck is power and current limited, much more so than what comes in from the utility. This somewhat mitigates the risk of a phase to neutral fault causing a wire to overheat and create a fire, in comparison to utility source.

Same as above regarding fault current still being able to trip the panel breaker. But yes, it becomes very difficult to overload anything to the point of fire in typical modern home wiring when you're limited to a grand total of 30 amps on a very sensitive overload.

 

[adoublee]

All my thoughts exactly except two points below. The safety cover protected switch (think missile launcher arming) to lift the ground pin on the inlet is the "least imperfect" way. In it's normally closed position, the ground is intact with no user intervention needed. You would have to lift a safety cover and flip the switch on purpose to lift the ground pin. Combined with a little sign that says what it does, it's probably the best we can do.


I think you might be overthinking this one. This would be no different than on normal utility power since there is no GFCI on the main breaker or utility pole. Put another way, any fault of any kind on any branch circuit in the house will behave the same way it would on utility power. Fault current will travel down the branch neutral or branch ground to the panel bond, and the branch circuit breaker will do whatever it is going to do (thermal, overload, gfci, afci, etc).


Same as above regarding fault current still being able to trip the panel breaker. But yes, it becomes very difficult to overload anything to the point of fire in typical modern home wiring when you're limited to a grand total of 30 amps on a very sensitive overload.

I'm not saying that a whole home electrical system is protected by GFCI, what I am saying is that circuit-level GFCI's installed in the home (in the bathroom for example) are not able to perform their function if there is not a path for ground faults to return to the source via the equipment ground conductor instead of the neutral conductor. With the ground conductor back to the source lifted, there cannot be any current on the ground wire back to the source. So a phase conductor touching something that is "grounded" will not produce current in the ground wire and will therefore not be sensed by the GFCI. It's just the nature of an ungrounded system which is what is created when lifting the ground pin. Now, you could also argue that an ungrounded current/energy limited system is less likely to hurt a person if they came in contact with the phase voltage since simultaneously touching something "earthed" would produce a path for current to cross the body, but that is where overthinking really starts to take hold. Long story short, it is ideal of GFCI devices are able to do their job.

 

[luebri]

All my thoughts exactly except two points below. The safety cover protected switch (think missile launcher arming) to lift the ground pin on the inlet is the "least imperfect" way. In it's normally closed position, the ground is intact with no user intervention needed. You would have to lift a safety cover and flip the switch on purpose to lift the ground pin. Combined with a little sign that says what it does, it's probably the best we can do.

I have not done anything yet, but after listening and consuming the Information from other regarding Ground Pin removal to use a whole panel interlock and generator inlet...

For my scenario with an existing 50A inlet and interlock, I was thinking if I did need to do this (for whatever reason could not or did not want to use my 12,000 watt portable generator) was to not to modify my 50amp generator inlet, nor my expensive 30' 50amp generator cord, but to simply remove the ground from the inexpensive 50amp to 30amp adapter I have. This adapter could easily then be labeled with a "warning" sticker. GROUND PIN REMOVED - ONLY FOR USE WITH FORD PRO POWER OUTLET.

Very little work involved, very little cost to replace or throw away if no longer needed.

EDIT - Posted pic of wrong adapter originally

 

[Maquis]

1. Downstream outlet GFCI's and the truck internal GFCI will de-sensitized when powered from the truck if the ground in the inlet is lifted. This is because a phase wire accidentally touching the metal case of an appliance would not cause current to flow on the ground and back to the source (truck), preventing the GFCI from sensing there is current escaping from the neutral return path. This poses some additional shock hazard, but is how things were in normal conditions before the advent of a ground wire to every outlet/appliance, and then the advent of so many required people-protection (highly sensitive) GFCI's.

This is totally incorrect. Since the ground and neutral are bonded in the main panel, the GFCI in the house (either breaker or receptacle) will trip. So will a non-GFCI breaker if the fault current is high enough.

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