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Old 05-31-2015, 12:35 PM   #131
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Originally Posted by TheLovelyBus View Post
Wanted to chime in since grounding and bonding is a big chunk of what I do for a living.

“Grounding” is the connection of an electrical system to earth. “Bonding” is the connection of two conductive things together to make them electrically common. 99% of what we call “grounding” is actually “bonding”....

Hope this is helpful to somebody, I know it's a bit long winded, sorry! Best of luck setting up your electrical systems, it’s a confusing subject for everyone!
Very good post which sums up a lot of what I write about in these forums. And note the I'm the author of the EC&M article you linked to above where I named the RPBG (Reveres Polarity Bootleg Ground) miswiring condition that's so dangerous. http://ecmweb.com/contractor/failure...esting-exposed

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Old 05-31-2015, 12:56 PM   #132
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Originally Posted by jmsokol View Post
Very good post which sums up a lot of what I write about in these forums. And note the I'm the author of the EC&M article you linked to above where I named the RPBG (Reveres Polarity Bootleg Ground) miswiring condition that's so dangerous. http://ecmweb.com/contractor/failures-outlet-testing-exposed.

Mike Sokol

Thanks! I'm glad to know I got it right, it means a lot coming from an expert such as yourself! I had no idea you were the author of that article, I came across it awhile back doing unrelated research and have had it bookmarked since. Small world, huh?
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Old 05-31-2015, 06:50 PM   #133
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Thanks! I'm glad to know I got it right, it means a lot coming from an expert such as yourself! I had no idea you were the author of that article, I came across it awhile back doing unrelated research and have had it bookmarked since. Small world, huh?
Yes, it is indeed a small world. I started writing my No~Shock~Zone blog because a few of my pro-sound buddies said they had been shocked from their tour bus, and nobody could answer why. I took on the project as an intellectual challenge and found that the majority of electricians and technicians didn't really understand the basic differences between bonding and grounding.

While designing the schematic for a high-current 3-light ground tester I discovered that a bootleg ground condition with the polarity reversed would not be detected by traditional methods, but would still appear to operate normally. However, the entire chassis of the gear would be energized to 120 volts with a low-impedance connection capable of supplying 20 or 30 amps of ground fault current. I named this mis-wired outlet condition an RPBG for Reverse Polarity Bootleg Ground, but had trouble getting the test gear manufacturers to believe that it operated as I described it. They claimed their test gear could discover an RPBG, but after building the test rig as I showed in my demonstration schematic, they all admitted they had never thought about this condition and had not included it in any of their testing or documentation.

I'm seeing the same sort of confusion from the generator manufacturers over the issue of Neutral-Ground bonding and why it's necessary for RV electrical systems, but not for home electrical systems. Seems like a very simple concept to me, which is why I came up with the Neutral-Ground bonding plug as a solution for using a portable inverter generator such as a Honda EU2000i for power their RV. I've had literally hundreds of emails from RV owners who've built and use my G-N bonding plug successfully, but none of these same generator manufacturers want to admit that it works. That's why forums such as this are so important to spreading this basic knowledge. For reference here's the link to my G-N bonding plug article. Generator Ground-Neutral Bonding | No~Shock~Zone

Mike Sokol
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Old 05-31-2015, 07:50 PM   #134
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Thanks for the link! We will end up making something like that if we use a portable generator. Making sure all of the electrical stuff is safe and efficient is another reason we are building a skoolie instead of buying an RV!
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Old 07-02-2015, 10:54 AM   #135
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AC ground to bus chassis

Mr Mike,

I have all my AC grounds isolated from my chassis ground. I will have ground from the campsite when plugged in, and I do verify that the campground is wired correct before per your example.

Now my question is my inverter is grounded to the chassis, so when I'm using it, my outlets are grounded to the chassis. Right now I'm manually plugging and unplugging the two. I want to put a switch in but all the ones I find only switch neutral and hot, not ground. Should I remove my inverter AC ground from chassis?
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Old 07-06-2015, 12:59 PM   #136
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Mr Mike,

I have all my AC grounds isolated from my chassis ground. I will have ground from the campsite when plugged in, and I do verify that the campground is wired correct before per your example.

Now my question is my inverter is grounded to the chassis, so when I'm using it, my outlets are grounded to the chassis. Right now I'm manually plugging and unplugging the two. I want to put a switch in but all the ones I find only switch neutral and hot, not ground. Should I remove my inverter AC ground from chassis?

From post #130 (worth reading in it's entirety):
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...You DO need to have your ground wire, NOT your neutral wire, securely bonded to the metal frame/skin of the RV.
The consensus is that you should always have an AC ground connected to your bus at a single point. If you do not then you risk having a hot skin condition. For instance, say you are plugged into shore power, have a circular saw connected into a bus outlet and are working outside with the tool. If that circular saw happens to have a fray in the wire it could electrify the skin of the bus without tripping the GFCI. That's a bad situation..
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Old 07-06-2015, 01:21 PM   #137
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Originally Posted by wmkbailey View Post
Now my question is my inverter is grounded to the chassis, so when I'm using it, my outlets are grounded to the chassis. Right now I'm manually plugging and unplugging the two. I want to put a switch in but all the ones I find only switch neutral and hot, not ground. Should I remove my inverter AC ground from chassis?
Check or test whether the inverter has an internal ground-neutral bond. If it does: you'll need to disconnect the inverter ground and neutral from the bus when using shore power, so that you don't create an extra ground-neutral bond in the shore power system you're plugging into. If the inverter does not: you should add a switchable ground-neutral bond to be installed when using the inverter and removed when using shore power.
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Old 07-06-2015, 02:57 PM   #138
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From post #130 (worth reading in it's entirety):


The consensus is that you should always have an AC ground connected to your bus at a single point. If you do not then you risk having a hot skin condition. For instance, say you are plugged into shore power, have a circular saw connected into a bus outlet and are working outside with the tool. If that circular saw happens to have a fray in the wire it could electrify the skin of the bus without tripping the GFCI. That's a bad situation..
All my AC grounds are connected together and not grounded to the Bus. When I'm on short power I get my ground from there. When connected to my inverter it is grounded to the bus through the inverter. I do this manually but plugging and unplugging them. I want to put in a switch but none of them switch the ground.

Sound like I need to keep my ground through the inverter, but need to find a switch that also switches ground. I'm surprised RV and Marine switches don't do this, they expect to have the grounds connected. If you don't check the shore power you could end up with 115 vac on the skin of the bus.
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Old 07-06-2015, 03:15 PM   #139
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Quote:
Originally Posted by wmkbailey View Post
All my AC grounds are connected together and not grounded to the Bus. When I'm on short power I get my ground from there. When connected to my inverter it is grounded to the bus through the inverter. I do this manually but plugging and unplugging them. I want to put in a switch but none of them switch the ground.

Sound like I need to keep my ground through the inverter, but need to find a switch that also switches ground. I'm surprised RV and Marine switches don't do this, they expect to have the grounds connected. If you don't check the shore power you could end up with 115 vac on the skin of the bus.
Perhaps I'm misunderstanding something here, but it sounds like you are saying that when you are connected to shore power your outlets are grounded through the shore power, but the bus skin is not grounded through the same shore power.

If this IS the case, then the scenario I described above is very possible. When on shore power you could potentially have a frayed wire touching the skin of the bus (pinched in a door, perhaps?) which will electrify it. No electrical safety devices will trigger.

Think of your bus as a washing machine for a moment. There are a bunch of live electrical components inside of a big, metal box. If those electrical components are insulated from the box and aren't somehow grounded to that metal box then if a wire comes loose from vibration or malfunction and that wire touches the box it will remain electrified. There is no path to ground to trigger the electrical safety devices.

On the other hand, if the metal box has a single connection to ground and a live wire contacts the metal box it will trigger the electrical safety devices and disable the appliance.
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Old 07-06-2015, 04:40 PM   #140
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Perhaps I'm misunderstanding something here, but it sounds like you are saying that when you are connected to shore power your outlets are grounded through the shore power, but the bus skin is not grounded through the same shore power.

If this IS the case, then the scenario I described above is very possible. When on shore power you could potentially have a frayed wire touching the skin of the bus (pinched in a door, perhaps?) which will electrify it. No electrical safety devices will trigger.

Think of your bus as a washing machine for a moment. There are a bunch of live electrical components inside of a big, metal box. If those electrical components are insulated from the box and aren't somehow grounded to that metal box then if a wire comes loose from vibration or malfunction and that wire touches the box it will remain electrified. There is no path to ground to trigger the electrical safety devices.

On the other hand, if the metal box has a single connection to ground and a live wire contacts the metal box it will trigger the electrical safety devices and disable the appliance.
This is very confusing. I thought I read a lot about never having your AC ground to your bus chassis when using shore power. If there is a miss wire you could end up with 115 vac on the bus skin. I guess I miss understood. Now I have no idea what to believe. I guess I will reread everything and hope I figure out out.
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