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[GMCnet] Question for the sparkies. [message #301442]

Thu, 02 June 2016 17:16

BobDunahugh

Messages: 2465
Registered: October 2010
Location: Cedar Rapids, IA

Karma: 11

Senior Member

I reused a GFI breaker in this remodel. It now powers only the Intellicharger that drops my 110 V AC to 12 V DC. It seems that the GFI breaker is bad. I can replace the GFI breaker with a standard breaker. Then just put in a GFI plug. Every circuit is GFI protected now. I'm questing if a GFI plug would be of benefit in this situation. They are cheep. And can't harm anything.Bob Dunahugh
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Re: [GMCnet] Question for the sparkies. [message #301449 is a reply to message #301442]

Thu, 02 June 2016 17:56

jhbridges

Messages: 8412
Registered: May 2011
Location: Braselton ga

Karma: -74

Senior Member

GFI dongles work well, as long as the neutral and ground aren't bonded someplace in the coach. They usually are in the genset, but if you use the standard GMC Plug N Play this won't matter. If you use a transfer switch, it wants to switch the ground as well as the neutral and hot(s).

--johnny

Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons. Braselton, Ga. I forgive them all, save those who hurt the dogs. They must answer to me in hell

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Re: [GMCnet] Question for the sparkies. [message #301451 is a reply to message #301442]

Thu, 02 June 2016 18:03

Matt Colie

Messages: 8547
Registered: March 2007
Location: S.E. Michigan

Karma: 7

Senior Member

BobDunahugh wrote on Thu, 02 June 2016 18:16

I reused a GFI breaker in this remodel. It now powers only the Intellicharger that drops my 110 V AC to 12 V DC. It seems that the GFI breaker is bad. I can replace the GFI breaker with a standard breaker. Then just put in a GFI plug. Every circuit is GFI protected now. I'm questing if a GFI plug would be of benefit in this situation. They are cheep. And can't harm anything.
Bob Dunahugh

Bob,

Why do you think you need a GFI for the converter?
It is a PD number - right? and the only thing that circuit feeds is that PD 92XX?
Just put in a regular breaker.

Matt

Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit

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Re: [GMCnet] Question for the sparkies. [message #301455 is a reply to message #301442]

Thu, 02 June 2016 18:12

Scott Nutter

Messages: 782
Registered: January 2015
Location: Houston/San Diego

Karma: 4

Senior Member

Bob,
Every time I plug my smart charger into a gfi plug it always trips the gfi. If works fine when plugged into a unprotected plug.
You might want to try plugging your smart charger into a gfi plug first to see if you get the same results as I. I'll be courteous to see if it works.
Scott

Scott Nutter 1978 Royale Center Kitchen, Patterson 455, switch pitch tranny, 3.21 final drive, Quad bags, Dave Lenzi super duty mid axle disc brakes, tankless water heater, everything Lenzi. Alex Ferrera installed MSD Atomic EFI Houston, Texas

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Re: [GMCnet] Question for the sparkies. [message #301458 is a reply to message #301451]

Thu, 02 June 2016 18:52

Matt Colie

Messages: 8547
Registered: March 2007
Location: S.E. Michigan

Karma: 7

Senior Member

BobDunahugh wrote

I reused a GFI breaker in this remodel. It now powers only the Intellicharger that drops my 110 V AC to 12 V DC. It seems that the GFI breaker is bad. I can replace the GFI breaker with a standard breaker. Then just put in a GFI plug. Every circuit is GFI protected now. I'm questing if a GFI plug would be of benefit in this situation. They are cheep. And can't harm anything.
Bob Dunahugh

Matt Colie wrote

Bob,

Why do you think you need a GFI for the converter?
It is a PD number - right? and the only thing that circuit feeds is that PD 92XX?
Just put in a regular breaker.

Matt

Guess What?
The LED over his head (only recently upgraded) just went on....

There is a good chance that some of these new things won't work with a GFI (GFCI) breaker.
And there is a simple reason and it has to do with how a GFI (as we geezers still call them) and how the new charging systems work and other power supplies work.

A GFI does its magic be comparing the current going out with the current coming back. If some is missing, it assumes it went were it should not and opens the circuit. That is a good plan, but it just can't work at 60Hz, so they feed another higher frequency signal into the conductor. Works great for a light bulb. But things like a PD 9260 are hardly light bulbs. The first thing that they do with the power you feed them is turn it into DC and then try clean it up so that they can chop it into little pieces that go better through a lighter transformer and someplace in there, it doesn't let the GFI sense signal get back. When that signal doesn't get back then the little processor (yes, they are now processor controlled) says, "OH No!" and Bang.....

So Bob, I guess you are back to a standard breaker for that.

And now I am reading stories of how a ham can pop GFIs all over the neighbor hood when he keys up.

Matt

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Re: [GMCnet] Question for the sparkies. [message #301460 is a reply to message #301458]

Thu, 02 June 2016 18:57

Mike Kilroy

Messages: 80
Registered: July 2006
Location: Farmersville, OH (near D...

Karma: 0

Member

Matt, I too am an old geezer and ham. I take exception to your high freq sent out of the gfi to detect missing current on 'return' leg. it just is not so. 60hz is fine to detect current in wire 1 being different by >30ma than in wire 2. Don't over complicate it.

----- Original Message -----
From: "Matt Colie"
To: gmclist@list.gmcnet.org
Sent: Thursday, June 2, 2016 7:52:32 PM
Subject: Re: [GMCnet] Question for the sparkies.

BobDunahugh wrote
> I reused a GFI breaker in this remodel. It now powers only the Intellicharger that drops my 110 V AC to 12 V DC. It seems that the GFI breaker
> is bad. I can replace the GFI breaker with a standard breaker. Then just put in a GFI plug. Every circuit is GFI protected now. I'm questing if a
> GFI plug would be of benefit in this situation. They are cheep. And can't harm anything.
> Bob Dunahugh

Matt Colie wrote
> Bob,
>
> Why do you think you need a GFI for the converter?
> It is a PD number - right? and the only thing that circuit feeds is that PD 92XX?
> Just put in a regular breaker.
>
> Matt

Guess What?
The LED over his head (only recently upgraded) just went on....

There is a good chance that some of these new things won't work with a GFI (GFCI) breaker.
And there is a simple reason and it has to do with how a GFI (as we geezers still call them) and how the new charging systems work and other power
supplies work.

A GFI does its magic be comparing the current going out with the current coming back. If some is missing, it assumes it went were it should not and
opens the circuit. That is a good plan, but it just can't work at 60Hz, so they feed another higher frequency signal into the conductor. Works great
for a light bulb. But things like a PD 9260 are hardly light bulbs. The first thing that they do with the power you feed them is turn it into DC and
then try clean it up so that they can chop it into little pieces that go better through a lighter transformer and someplace in there, it doesn't let
the GFI sense signal get back. When that signal doesn't get back then the little processor (yes, they are now processor controlled) says, "OH No!"
and Bang.....

So Bob, I guess you are back to a standard breaker for that.

And now I am reading stories of how a ham can pop GFIs all over the neighbor hood when he keys up.

Matt

--
Matt & Mary Colie - Members GMCMI, GMCGL, GMCES
'73 Glacier 23 - Still Loving OE Rear Drum Brake with Applied Control Arms
Now with both true Keyless and remote entry
SE Michigan - Twixt A2 and Detroit

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Mike (AC8V) & Vickie Kilroy
'73 Canyon Land 26' sidebath
455/ceramic filled crossovers

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Re: [GMCnet] Question for the sparkies. [message #301464 is a reply to message #301458]

Thu, 02 June 2016 19:30

Jim Miller

Messages: 501
Registered: March 2008

Karma: 10

Senior Member

On Jun 2, 2016, at 7:52 PM, Matt Colie wrote:
>
> A GFI does its magic be comparing the current going out with the current coming back. If some is missing, it assumes it went were it should not and
> opens the circuit. That is a good plan, but it just can't work at 60Hz, so they feed another higher frequency signal into the conductor.

The world is full of inductive loads - motors, lamp ballasts, switching power supplies in every electronic appliance….and also RV power converters. One thing inductive loads do very well is snub high frequency signals. For this reason there’s no way the described mode of operation would be viable for such a circuit breaker in the modern world because it would constantly be tripping...even on electrically perfect circuits.

A GFI works on the very simple principle of a differential current transformer - the current going through the hot wire must be equal to the current returning in the neutral with an allowable delta of only 0.01 amp or thereabouts.

73, Jim N8ECI
--
Jim Miller
1977 Eleganza
1977 Royale
Hamilton, OH

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Jim Miller 1977 Eleganza II 1977 Royale Hamilton, OH

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Re: [GMCnet] Question for the sparkies. [message #301500 is a reply to message #301464]

Fri, 03 June 2016 09:01

Matt Colie

Messages: 8547
Registered: March 2007
Location: S.E. Michigan

Karma: 7

Senior Member

Jim Miller wrote on Thu, 02 June 2016 20:30

On Jun 2, 2016, at 7:52 PM, Matt Colie wrote:
>
> A GFI does its magic be comparing the current going out with the current coming back. If some is missing, it assumes it went were it should not and
> opens the circuit. That is a good plan, but it just can't work at 60Hz, so they feed another higher frequency signal into the conductor.

The world is full of inductive loads - motors, lamp ballasts, switching power supplies in every electronic appliance....and also RV power converters. One thing inductive loads do very well is snub high frequency signals. For this reason there's no way the described mode of operation would be viable for such a circuit breaker in the modern world because it would constantly be tripping...even on electrically perfect circuits.

A GFI works on the very simple principle of a differential current transformer - the current going through the hot wire must be equal to the current returning in the neutral with an allowable delta of only 0.01 amp or thereabouts.

73, Jim N8ECI
Mike Kilroy wrote on Thu, 02 June 2016 19:57
Matt, I too am an old geezer and ham. I take exception to your high freq sent out of the gfi to detect missing current on 'return' leg. it just is not so. 60hz is fine to detect current in wire 1 being different by >30ma than in wire 2. Don't over complicate it.

Jim and Mike,

I have no interest in over complicating the situation, but, if I am correct, Bob has a complicated situation. If this explains it, then he has a non-issue to deal with that does not require attention other than eliminating the GFI.

There is a problem explained to me by an engineer at one of the manufactures years ago....
That problem is that 60hz is too slow (16ms per cycle) to collect enough signal in a low drain situation in the time required by the regulation. Yes, it could be doable at 60Hz, but the practical matter is that it just is not (or was not then). Big drains are no issue. It seems that they did use both the line frequency and the added signal for safety. I had button holed the poor guy while at an engineers event, so I got him a replacement beverage and asked more. I did ask specifically about inductive loads and the high frequency. His response was that they did not matter. They did not absorb enough of the test signal and so did not need to return any. I do not remember the entire discussion and I did not ask about switching power supplies as they were not yet common. He did mention that they had had some difficulty with small appliances that used a bridge at the input to drive a small dc motor. They advised the manufacture of these to put a little cap on the line input. They told them GFI trip was a result of spikes fed back into the line by the cheap motor. I believe that Bob has a higher technology version of the same issue. Some of those manufactures did do this, the others just told the angry buyers to not use the device in the kitchen or bathroom. I believe that Bob has a higher technology version of this same issue.

Matt

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Re: [GMCnet] Question for the sparkies. [message #301501 is a reply to message #301442]

Fri, 03 June 2016 09:16

JohnL455

Messages: 4447
Registered: October 2006
Location: Woodstock, IL

Karma: 12

Senior Member

To put what Matt is saying in another way (my heads way). There may be some phase (time) shift between the H and N waves so though the amplitudes may match, they are no longer equal/opposte signals and you get a nuisance trip.

John Lebetski
Woodstock, IL
77 Eleganza II

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Re: [GMCnet] Question for the sparkies. [message #301504 is a reply to message #301501]

Fri, 03 June 2016 09:33

Mike Kilroy

Messages: 80
Registered: July 2006
Location: Farmersville, OH (near D...

Karma: 0

Member

To be clear, there is not a high freq sig injected, nor is there any
phase shift.

When you have two wires, one sending current out, other bringing it
back, they are the same and cannot have phase shift between them.

But to exonerate Matt's comment, he is sorta right on some of the
fancier GFCI units nowadays... these have a second detection unit
inside that does inject a small 120hz sig to detect for neutral to
ground shorts downstream.

Very easy to understand full description:
http://www.rhtubs.com/GFCI/GFCI.htm

On 6/3/2016 10:16 AM, John R. Lebetski wrote:
> To put what Matt is saying in another way (my heads way). There may be some phase (time) shift between the H and N waves so though the amplitudes may
> match, they are no longer equal/opposte signals and you get a nuisance trip.

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'73 Canyon Land 26' sidebath
455/ceramic filled crossovers

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Re: [GMCnet] Question for the sparkies. [message #301512 is a reply to message #301500]

Fri, 03 June 2016 14:04

Dave Mumert

Messages: 272
Registered: February 2004
Location: Olds, AB, Canada

Karma: 0

Senior Member

Hi All

Actually both of you are correct.

Most of us think the GFCI only monitors an imbalance in the line and neutral wires, as Jim says, this is done with a simple current
transformer.

The more difficult job the GFCI must do is protect against a neutral to ground fault. This is where the higher frequency is used.
Many manufacturers use the 120 Hz output from the bridge rectifier, but some use a higher frequency oscillator to inject a small
current into both the hot and neutral lines. Any ground to neutral fault will cause the neutral wire to have excess current which
will trip the breaker.

http://www.idea2ic.com/GFI/GFICs.html
http://www.idea2ic.com/GFI/LM1851.pdf
https://www.nema.org/Products/Documents/NEMA-GFCI-2012-Field-Representative-Presentation.pdf

Dave Mumert

> -----Original Message-----
> From: Gmclist [mailto:gmclist-bounces@list.gmcnet.org] On Behalf Of Matt Colie
> Sent: Friday, June 03, 2016 8:01 AM
> To: gmclist@list.gmcnet.org
> Subject: Re: [GMCnet] Question for the sparkies.
>
> Jim Miller wrote on Thu, 02 June 2016 20:30
>> On Jun 2, 2016, at 7:52 PM, Matt Colie wrote:
>>>
>>> A GFI does its magic be comparing the current going out with the
>>> current coming back. If some is missing, it assumes it went were it
>>> should not and opens the circuit. That is a good plan, but it just can't work at 60Hz, so they feed another higher frequency
signal
> into the conductor.
>>
>> The world is full of inductive loads - motors, lamp ballasts,
>> switching power supplies in every electronic appliance....and also RV
>> power converters. One thing inductive loads do very well is snub high frequency signals. For this reason there's no way the
> described mode of operation would be viable for such a circuit breaker in the modern world because it would constantly be
> tripping...even on electrically perfect circuits.
>>
>> A GFI works on the very simple principle of a differential current
>> transformer - the current going through the hot wire must be equal to the current returning in the neutral with an allowable
delta of
> only 0.01 amp or thereabouts.
>>
>> 73, Jim N8ECI
>> Mike Kilroy wrote on Thu, 02 June 2016 19:57
>>> Matt, I too am an old geezer and ham. I take exception to your
>>> high freq sent out of the gfi to detect missing current on 'return' leg. it just is not so. 60hz is fine to detect current
in wire 1 being
> different by >30ma than in wire 2. Don't over complicate it.
>
> Jim and Mike,
>
> I have no interest in over complicating the situation, but, if I am correct, Bob has a complicated situation. If this explains
it, then he has
> a non-issue to deal with that does not require attention other than eliminating the GFI.
>
> There is a problem explained to me by an engineer at one of the manufactures years ago....
> That problem is that 60hz is too slow (16ms per cycle) to collect enough signal in a low drain situation in the time required by
the
> regulation. Yes, it could be doable at 60Hz, but the practical matter is that it just is not (or was not then). Big drains are
no issue. It
> seems that they did use both the line frequency and the added signal for safety. I had button holed the poor guy while at an
> engineers event, so I got him a replacement beverage and asked more. I did ask specifically about inductive loads and the high
> frequency. His response was that they did not matter. They did not absorb enough of the test signal and so did not need to
return
> any. I do not remember the entire discussion and I did not ask about switching power supplies as they were not yet common. He
did
> mention that they had had some difficulty with small appliances that used a bridge at the input to drive a small dc motor. They
advised
> the manufacture of these to put a little cap on the line input. They told them GFI trip was a result of spikes fed back into the
line by
> the cheap motor. I believe that Bob has a higher technology version of the same issue. Some of those manufactures did do this,
the
> others just told the angry buyers to not use the device in the kitchen or bathroom. I believe that Bob has a higher technology
version
> of this same issue.
>
> Matt
> --
> Matt & Mary Colie - Members GMCMI, GMCGL, GMCES
> '73 Glacier 23 - Still Loving OE Rear Drum Brake with Applied Control Arms Now with both true Keyless and remote entry SE Michigan
-
> Twixt A2 and Detroit
>
> _______________________________________________
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> Unsubscribe or Change List Options:
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