Open ground question

[Jbird]

When testing my coach outlets with a plug in tester it indicates " open ground" on all circuits when I am powering with my portable generator. The GFI circuits do not break but show the same open ground. My tester plugged directly into the Honda generator also shows open ground.
A different power source to my coach, all circuits test properly. Can anyone explain why I show open ground in coach and at generator and am I in any danger in coach using generator for power. Thanks to the knowledgeable in advance

[Salvo]

The only argument the pro bonding folks have is code, code, code. That's no argument at all! The RV code is constantly changing. They don't know what the H they're doing. It's perfectly legal to operate an unbonded generator in a RV that's rated something like 4000W or less. Why 4000W? It's arbitrary. Just 20 mA current through the heart will kill you.

The argument against bonding is plain and clear.

1. You can't drive a metal rod 5 feet deep in the ground each time you start the generator. It's improbably RV electronics will survive a lightning strike anyways. Therefore forget the ground rod.

2. Bonding generator neutral to RV chassis serves no purpose. There are no benefits. Since there are no 100 ft high power lines involved, lightning is not an issue. It is significantly less safe. You are just one fault away from electrocution.

3. An unbonded system together with a 3-lite ground fault monitor is virtually bullet proof.

Sal

[MPD56]

SaltiDawg wrote:

MPD56 wrote:
...

But my point is that even connecting a generator to a RV is not a simple play & play event.

I have not so much as expressed an opinion on the subject

As I said in my first post in this thread, "While I do have an opinion, I have zero RV experience and thus no standing to weigh in. However, I could not allow a mistaken Submarine reference be introduced into the mix."

Thanks again for your knowledgeable input. It's what makes this forum great.

[SaltiDawg]

MPD56 wrote:
...

But my point is that even connecting a generator to a RV is not a simple play & play event.

I have not so much as expressed an opinion on the subject

As I said in my first post in this thread, "While I do have an opinion, I have zero RV experience and thus no standing to weigh in. However, I could not allow a mistaken Submarine reference be introduced into the mix."

[MPD56]

SaltiDawg wrote:

MPD56 wrote:
...

A ship at sea is wired to code. When it is on shore power, does the power cord have a ground conductor? The electrical code will also determine that.

Shorepower is ungrounded three phase 450 Volt, 60 Hz, power to a submarine.

Thanks for the reply and information.

The Lake Freighters and Ocean Vessel’s I’ve hooked up get a 575 volt 600 amp 3/phase power cord with a ground conductor and Electrical Inspected. We do on occasion supply a three phase step down transformer (575 to 440) that is grounded and bonded to the electrical code. We used to use 2400 volt overhead cranes to unload and load; this is why it is so important to understand grounding methods.

But my point is that even connecting a generator to a RV is not a simple play & play event.

[SaltiDawg]

MPD56 wrote:
...

A ship at sea is wired to code. When it is on shore power, does the power cord have a ground conductor? The electrical code will also determine that.

Shorepower is ungrounded three phase 450 Volt, 60 Hz, power to a submarine.

[MPD56]

Always an interesting RV forum subject. As I always said “Lots of people can hook up a light bulb or speaker and make it work, but is it safe”?
In Canada the Electrical Safety Authority is the maker and keeper of the Electrical Code. Can they make a code that is 100% safe, well they try? Do they think that they can inspect every RV hooked up to generator before the consumer starts it up, of course not? This is why there is going to be two side on this debate till the end of time on a RV forum. On an Electrical Forum, there would be only one page of posts. It comes down to electrical theory and the best way to make it safe. When you’re wiring a house do you go on a forum to find about if you should ground it.

No one from a keyboard can tell you if your wiring is 100% safe, but then again I’m old and don’t know if some Electrical Inspections can be done on Skype?

A ship at sea is wired to code. When it is on shore power, does the power cord have a ground conductor? The electrical code will also determine that.

[SaltiDawg]

The ungrounded electrical system provides for BOTH enhanced equipment reliability and as an (arguably unintended) consequence also provides for increased personnel safety.

[Salvo]

The UNbonded ship link didn't work for me. Googling this topic gives interesting results. Evidently all ships use an unbonded electrical system. You do NOT want to lose ship power. Bad things happen.

Ships have a 3-lite ground fault detector. This detector will indicate the presence of the first fault. This fault needs to be cleared before a second fault occurs.

This power point presentation is interesting. Slide 4 states they use and unbonded system NOT for safety, but for reliability. Don't know why they say that. Clearly, safety is significantly enhanced. If you got a weak stomach, don't look at the last few slides.

Sal

[Salvo]

Thanks for setting the record straight. As I see it, it's extremely dangerous to bond dc or ac in a metal hulled vehicle or ship.

There are no power poles (telephone poles) on a sub. Hence no problem with lighting strikes. Absolutely no reason to bond. RVs are in similar circumstance.

SaltiDawg wrote:

SCClockDr wrote:
...

That is how I see it. 22 years Naval experience living in a steel pipe (submarine) for 10 of them. The neutral & ground were bonded in that environment.

Retired 24 year submariner here. Generated lots of electricity on three Nukes and two Diesel boats. UNgrounded three phase 450 Volt power on the Nukes, UNgrounded DC on the WWII Diesel Boats. Spent many hours and more hours chasing grounds.

"320-1.2.1.1 System Grounding. All ac distribution systems on U.S. Navy ships are ungrounded." ...
"Ungrounded electrical systems have no intentional
connections between the electrical conductors and the ground (ship’s hull). These systems were chosen for their
higher reliability because grounding of a single conductor will not typically produce enough fault current to
interrupt power. Grounds must be removed as soon as possible to maintain this advantage, however, because a
second ground on another phase will cause a power loss and could endanger personnel."

Additionally, at a 110V Shipboard receptacle the ground connector is connected separately to the hull and is not "bonded" to the other two connectors.

While I do have an opinion, I have zero RV experience and thus no standing to weigh in. However, I could not allow a mistaken Submarine reference be introduced into the mix.

UNgrounded Shipboard Electrical Distribution

[Salvo]

That is not correct. If you grab hot and neutral, there is no difference between an unbonded and bonded system. If there's GFI, you may not get shocked. It doesn't matter if it's bonded or not.

You may want to research how GFI works!

Sal

ktmrfs wrote:

true if you ONLY grab hot OR neutral. If for some reason you get across HOT AND NEUTRAL your going to get at least a nasty shock in an unbonded system with a high impedance to any other ground path, even with a GFI.

[SaltiDawg]

SCClockDr wrote:
...

That is how I see it. 22 years Naval experience living in a steel pipe (submarine) for 10 of them. The neutral & ground were bonded in that environment.

Retired 24 year submariner here. Generated lots of electricity on three Nukes and two Diesel boats. UNgrounded three phase 450 Volt power on the Nukes, UNgrounded DC on the WWII Diesel Boats. Spent many hours and more hours chasing grounds.

"320-1.2.1.1 System Grounding. All ac distribution systems on U.S. Navy ships are ungrounded." ...
"Ungrounded electrical systems have no intentional
connections between the electrical conductors and the ground (ship’s hull). These systems were chosen for their
higher reliability because grounding of a single conductor will not typically produce enough fault current to
interrupt power. Grounds must be removed as soon as possible to maintain this advantage, however, because a
second ground on another phase will cause a power loss and could endanger personnel."

Additionally, at a 110V Shipboard receptacle the ground connector is connected separately to the hull and is not "bonded" to the other two connectors.

While I do have an opinion, I have zero RV experience and thus no standing to weigh in. However, I could not allow a mistaken Submarine reference be introduced into the mix.

UNgrounded Shipboard Electrical Distribution

[ktmrfs]

Salvo wrote:
That's the beauty of an unbonded system. Chances of GFI tripping are really remote! That means, YOU, getting killed from 120V is virtually non-existent.

Think of it as lines of defense. You're dead meat if you make 120V contact if bonded. There is no line of defense. Some receptacles have GFI. Now you got one line of defense, that is as long as the GFI is functional.

In an unbonded system, your first line of defense is the fact that neutral is not bonded to ground. Ground is isolated. You can grab a hold of either hot or neutral and not get fried. You can add GFI to the mix, and now you have a second line of defense.

IMO, anybody who claims the bonded system is safer doesn't fully understand the issues. You can always test if a short occurred between ground and hot/neutral by using a 3-lite tester.

Sal

ktmrfs wrote:

Actually with respect to GFI outlets, the chances of them trippinng when connected to a unbonded generator is pretty remote.

true if you ONLY grab hot OR neutral. If for some reason you get across HOT AND NEUTRAL your going to get at least a nasty shock in an unbonded system with a high impedance to any other ground path, even with a GFI.

[camperpaul]

Just over one hundred years ago, the subject of grounded vs. ungrounded Neutral was debated in North America and other parts of the world.

In most of Europe, the standard is 220 Volts 50 Hz with both sides of the line ungrounded (there is no neutral).

In North America, there are a bunch of standards, e.g.:

1. Split phase 240 Volts with 120 Volts each side of Neutral.

2. "Y" connected three phase 208 Volts with 120 Volts from each hot leg to Neutral.

3. "Delta" connected three phase 240 Volts with no Neutral.

There are a few other obscure US standards.

The safety debate still goes on and on and on …

[Salvo]

That's the beauty of an unbonded system. Chances of GFI tripping are really remote! That means, YOU, getting killed from 120V is virtually non-existent.

Think of it as lines of defense. You're dead meat if you make 120V contact if bonded. There is no line of defense. Some receptacles have GFI. Now you got one line of defense, that is as long as the GFI is functional.

In an unbonded system, your first line of defense is the fact that neutral is not bonded to ground. Ground is isolated. You can grab a hold of either hot or neutral and not get fried. You can add GFI to the mix, and now you have a second line of defense.

IMO, anybody who claims the bonded system is safer doesn't fully understand the issues. You can always test if a short occurred between ground and hot/neutral by using a 3-lite tester.

Sal

ktmrfs wrote:

Actually with respect to GFI outlets, the chances of them trippinng when connected to a unbonded generator is pretty remote.