Transfer Switch Gameplan - Thoughts?

[HammaMan]

Finally came across that old vid from mike holt where they're electrifying the ground rod. Figured some may find it informative.

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[dafish]

Huh. I'd no idea "ground" was such a poor conductor. Hard to believe if I'd not seen it. Am I to believe I've a ground rod driven 80' into the ground at my home? My breakers work!

 

[dafish]

I wouldn't say they're the same. They're bonded, but current shouldn't be on the ground but can be on the neutral as it's returning to the source.

Understood. Was what I intended to imply.

With the typical install of a generator interlock, often done with a 2 pole breaker, any portable generator connected to such wired configuration will be passing the delta of L1 and L2 back to the generator equally on the ground and the neutral. That's not to code, but that's just what you get with a breaker interlock.

Oops! Would you please expand on this a bit? I use a exactly that: 2 pole breaker with a mechanical safety interlock to a generator that does not have (apparently, since I've zero problems) a bonded ground at the genset.

When I went this route after some informal testing, I did not expect, still don't believe, I am carrying any power across the ground. I'm of the belief (and untrained, as we can see) that N is carrying any unbalanced 120V current back to the gen set. Now if I was ground/neutral bonded in the gen set, well OK, now I can see how the two are effectively in parallel. But only then. Was that implied in your above, or do I not understand something?

Let me be super clear: This is NOT me arguing!! I'm trying to find out what I apparently don't know (among the huge list), and doing so by sharing what I thought.

 

[dafish]

DO NOT do that. Don't touch the truck. I wouldn't be modifying generators either. The current is trying to get back to the generator.

Lets agree I don't know much, but isn't your plan of lopping off the ground at the plug and mine of separating N/G at the gen both pushing all the delta current over the "N"? Your way is fully dependent on a fully insulated genset while mine at least extends the house ground to the generator. To this layman that's maybe even a better plan (flame suit on).

Not that I have any idea how to do that on the truck. of course, just that it seems reasonable. Course it would likely F up the truck side GFCI, but then I don't like the damn things anyway.

 

[HammaMan]

Lets agree I don't know much, but isn't your plan of lopping off the ground at the plug and mine of separating N/G at the gen both pushing all the delta current over the "N"? Your way is fully dependent on a fully insulated genset while mine at least extends the house ground to the generator. To this layman that's maybe even a better plan (flame suit on).

Not that I have any idea how to do that on the truck. of course, just that it seems reasonable. Course it would likely F up the truck side GFCI, but then I don't like the damn things anyway.

What does a contiguous ground buy you? The GFI is still in place, so nuisance trips are a possibility.

 

[Hullguy]

“I wouldn't say they're the same. They're bonded, but current shouldn't be on the ground but can be on the neutral as it's returning to the source. With the typical install of a generator interlock, often done with a 2 pole breaker, any portable generator connected to such wired configuration will be passing the delta of L1 and L2 back to the generator equally on the ground and the neutral. That's not to code, but that's just what you get with a breaker interlock.”
If this were true people would be getting killed. The only time there should be current on a ground is during a fault that will cause the breaker to trip.
Most portable generators do use the existing grounding system for safety and stabilization.

 

[Hullguy]

All of the building's wiring is as it should be. You're taking exception to the little PB bypass unit that isn't part of the structure. The ground for that run is in the same spot the utility's ground is with the exception being that it's cord run has GFI protection on it.

I'm still waiting for your failure mode analysis. What is this mystery failure mode you hint at but do not share? I ask about your failure suggestion each time, and it's yet to be answered. I'm turning blue over here waiting on it.

There is absolutely no connection between the Powerboost ground and the utility ground if you cut the ground on the dogbone plugged into the Powerboost. Show me how it is!
Failure mode analysis? None of your plumbing in the house is connected to the Powerboosts ground in your scenario. If there is stray voltage on the pipe you are the path to ground

 

[dafish]

“I wouldn't say they're the same. They're bonded, but current shouldn't be on the ground but can be on the neutral as it's returning to the source. With the typical install of a generator interlock, often done with a 2 pole breaker, any portable generator connected to such wired configuration will be passing the delta of L1 and L2 back to the generator equally on the ground and the neutral. That's not to code, but that's just what you get with a breaker interlock.”

If this were true people would be getting killed. The only time there should be current on a ground is during a fault that will cause the breaker to trip.

Most portable generators do use the existing grounding system for safety and stabilization.

In Hamma's absense allow me to reply vis a vis the second paragraph.

In the case of the Ford, where it is known to have a bonded ground neutral, it is absolutely the case that current will travel over both when connected to home wiring. There should be zero debate on that. In fact, logic should tell us that from the simple evidence of GFCi's popping that there is current on the ground, right? One mans opinion of course, but it's hard to beat physics

Anyway, In a home ground does not normally carry current because (and this is vital) it only bonds at the main panel. Note this is after opposing L1 and L2 currents neutralize. If you bond up or down stream of that the wire in between is effectively in parallel and there will be current on both paths (buy and large relative to their resistance). Code normally prohibits this although there are some edge cases.

The root, and let's recall I'm merely a laymen, is that Ford elected, probably had to, make it support GFCI as well as portable devices (job site etc) directly. That required that Ford include a "ground". Fords is obviously not one to earth, it's a stretch to call it a "ground", but that's the wire it runs over so... How much value that has is up to you..

As to code compliance, I'm of the opinion that code serves two main purposes (safety and consistency), and that it cannot and does not address all situations. BTW, another point Hamma made was "labeling". The wise man does this. EG: I use 14-50 receptacles all the time, even on circuits that don't support 50 amps. Perfectly code compliant (because code doesn't address this at all), so I label.

I grant you some will lean towards code compliance at all costs, others are comfortable getting off the ranch in select cases, and with due diligence. BTW, a substantial number, perhaps close to half, of "electricians" violate code every day from simple ignorance, impatience, and/or profit.

One mans thoughts of course, worth no more than the reader paid for it.

 

[dafish]

I ask you all, if you cut the ground at the truck, where does it connect to the utility ground or the house grounding system? Why has the NEC had a provision that the neutral be bonded only once at the service since the early 20’s if you think it’s not necessary?

Do you see the conflict sir? The truck is attempting to provide a second bonded neutral/ground. Note your last sentence. that's the root of the problem. The GFCI CT is seeing current on the ground where it shouldn't be and tripping. (ok, that's an assumption, I'm new to Ford side of this).

 

[Egilson1]

let me throw some more mud on this discussion. Do you each consider the PB to be a vehicle mounted generator? And if so would 250.34 of the nec then apply? Does that change the discussion?

 

[Snakebitten]

Tiny houses (RV's) are much less controversial with regards to the Mighty Rolling Grid Powerboost.

In 60 seconds you are running the HVAC, hot water heater, water pressure pump, all kitchen appliances, the TVs and internet service, and of course the lights.

That rod shoved deep into the ground doesn't even come into play. ? It sure does complicate things.

 

[Hullguy]

In Hamma's absense allow me to reply vis a vis the second paragraph.

In the case of the Ford, where it is known to have a bonded ground neutral, it is absolutely the case that current will travel over both when connected to home wiring. There should be zero debate on that. In fact, logic should tell us that from the simple evidence of GFCi's popping that there is current on the ground, right? One mans opinion of course, but it's hard to beat physics

Anyway, In a home ground does not normally carry current because (and this is vital) it only bonds at the main panel. Note this is after opposing L1 and L2 currents neutralize. If you bond up or down stream of that the wire in between is effectively in parallel and there will be current on both paths (buy and large relative to their resistance). Code normally prohibits this although there are some edge cases.
If a ground is carrying current it should trip the circuit breaker. I know of no edge cases in the NEC.
The root, and let's recall I'm merely a laymen, is that Ford elected, probably had to, make it support GFCI as well as portable devices (job site etc) directly. That required that Ford include a "ground". Fords is obviously not one to earth, it's a stretch to call it a "ground", but that's the wire it runs over so... How much value that has is up to you..
There is a difference between bonding and grounding. It’s part of the reason Article 250 In the NEC is so large. To be honest, I don’t feel this truck was ever meant to power a dwelling. It can be done but you need the correct UL approved electrical equipment installed by the provisions of the NEC.

As to code compliance, I'm of the opinion that code serves to main purposes (safety and consistency), and that it cannot and does not address all situations. BTW, another point Hamma made was "labeling". The wise man does this. EG: I use 14-50 receptacles all the time, even on circuits that don't support 50 amps. Perfectly code compliant (because code doesn't address this at all), so I label.
The NEC does not address all situation. This is why it is updated every 3 years. Labeling is required by Code. NEC also requires the installation of all electrical equipment to be installed as the manufacturer requires. This is the Listing and Labeling portion of the Code.
You can use the NEMA 14-50 as long as the wiring is sized correctl. But, if you pug as 30 amp supply into it, it must have a 30 amp breaker.
I grant you some will lean towards code compliance at all costs, others are comfortable getting off the ranch in select cases, and with due diligence. BTW, a substantial number, perhaps close to half, of "electricians" violate code every day from simple ignorance, impatience, and/or profit.
“Lean” toward Code compliance? As a Licensed Master Electrician and all other electricIan’s it’s not acceptable to my trade! As far as anyone violating the Code, (who would hire someone to do electrical work who is ignorant, or impatient? They are incompetent!), this is why you have the Authority Having Jurisdiction, ie. the Wire Inspector, to check any and all electrical installations. And this is why I have asked anyone who has cut the ground off the cable from the Powerboost to have it inspected and passed by a wire inspector!

One mans thoughts of course, worth no more than the reader paid for it.

Agreed. But my thoughts are through my training, experience, and continuing education every 3 years required to keep my license.

 

[Hullguy]

let me throw some more mud on this discussion. Do you each consider the PB to be a vehicle mounted generator? And if so would 250.34 of the nec then apply? Does that change the discussion?

Yes it is. And yes it does

 

[HammaMan]

Let's restate everything here so we're clear.

Issue: PB's GFI inverter trips upon connecting to a generator-to-structure receptacle while having no issues when connected to portable generators.

Cause: The structure's electrical system contains a neutral ground bond allowing current to return to the generator on the grounding conductor.

Solution: Use a marked adaptor to float PB's GFI invertor grounding conductor at point before entering structure.

Risks: As of yet none identified. Vehicle is insulated from earth and if such conditions manifest that do earth the vehicle, such conditions would trip the GFI before presenting an electrocution risk to any life (not just that of adults).

Enhanced variables vs traditional breakers / power sources: Instantaneous trip at 32 amps. Unlike a 15 amp circuit breaker that requires 10-100 seconds to trip at 32 amps.

 

[dafish]

Let's restate everything here so we're clear.

Issue: PB's GFI inverter trips upon connecting to a generator-to-structure receptacle while having no issues when connected to portable generators.

Cause: The structure's electrical system contains a neutral ground bond allowing current to return to the generator on the grounding conductor.

Solution: Use a marked adaptor to float PB's GFI invertor grounding conductor at point before entering structure.

Risks: As of yet none identified. Vehicle is insulated from earth and if such conditions manifest that do earth the vehicle, such conditions would trip the GFI before presenting an electrocution risk to any life (not just that of adults).

Enhanced variables vs traditional breakers / power sources: Instantaneous trip at 32 amps. Unlike a 15 amp circuit breaker that requires 10-100 seconds to trip at 32 amps.

Hamma, Let me reword this and see if I'm understanding you correctly:

Issue: PB's GFCI trips upon connecting to a generator-to-structure receptacle. A portable generators, so long as it's floating ground, does has no problems.

Cause: The presence of two neutral/ground bonds allowing current to return to the generator on the grounding conductor.

Solution: Eliminate one of the bonds:
A: Find a way to temporarily disable the panel bond.
B: Eliminate the temporary power supply (PB or bonded generator) bond.
C: Disconnect the ground link at some point between Panel and temporary power supply.

Assuming I do correctly understand and have worded correctly and withing this laymans undertanding, I'm not sure I see a problem with "C". House ground? Still there, still works, devices remain protected. Temporary power supply ground? Not less effective than it ever was (which I sorta question).

"Risk" domain: I don't see one. One side of the adapter see the home ground, the other sees the generator. Make sure the "adapter" is rubber/plastic so there isn't some no-mans land of risk and it seems fini.

Hamma, why use an adapter? Are you thinking a short 14-50F <-> 14-50P dedicated to this use and labeled as same? This instead of altering a longer cord that can otherwise remain multi-purpose?

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