ramsy
Roger Ruhle dba NoFixNoPay
- Location
- LA basin, CA
- Occupation
- Service Electrician 2020 NEC
You never heard of Rockwell Automation's Retro Encabulator, and the modial interaction of magneto reluctance and capacitive duractance.
arc fault/dual function breaker tripping.
- Thread starter billydrowne
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kwired
Electron manager
- Location
- NE Nebraska
Why does a GFCI trip immediately if you touch load side neutral to ground even when there is no load connected at the time?
Basic concept of GFCI operations should not trip until there is current but they will trip every time you touch unloaded neutral to ground.
Seem to be having difficulty finding information on this, probably just using wrong key words in the search, but did find this:
They call it neutral to ground fault detection but it would also allow it to detect a fault on the "phase conductor" to another same "phase conductor" in about the same manner.
ptonsparky
Tom
- Occupation
- EC - retired
I always figured you had current flow, but until Gar set me straight, after a great deal of difficulty, I didn’t know how much.
hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
I would think the neutral/ground detection would work seperately from the ground fault circuit, and use a very small amount of current just like an ohmmeter circuit to detect the connection.
ptonsparky
Tom
- Occupation
- EC - retired
That is what I thought, too. I was using my Fluke on the the milliamperes range, neutral to EG, to see at what level they would trip. Most peaked at 4-6 ma. Between Gar and Kwire they got thru my thick skull that I was short circuiting the detection circuit via my meter and I was lucky I hadn’t damaged the meter. Fluke fusing is good. It blew first.
kwired
Electron manager
- Location
- NE Nebraska
Look at drawing I posted. Injected volts is via a CT just in reverse mode from what the detection CT is.
Short the output neutral to ground and the circuit loop goes back through neutral/ground bonding point and back to the GFCI via the input neutral. Same CT that is providing normal current differential detection sees current from this second source flowing one way but not the other so no canceling of magnetic fields and initiates the trip process.
romex jockey
Senior Member
- Location
- Vermont
- Occupation
- electrician
Probably because there's always a dif betwixt N&G ,and more so with distance to the serving Xformer w/ VD
Juxtaposed to not much dif betwixt 5 and 30 millionths of an amp
~RJ~
mbrooke
Batteries Included
- Location
- United States
- Occupation
- Technician
Hmmmm....
What is the difference between ground current and ground fault here?
What is the difference between ground current and ground fault here?
romex jockey
Senior Member
- Location
- Vermont
- Occupation
- electrician
perhaps the 'safety' part of this >>>https://en.wikipedia.org/wiki/Earthing_system helps ~RJ~
kwired
Electron manager
- Location
- NE Nebraska
Install a temp service for construction with a GFCI receptacle adjacent to the service disconnect. No loads in use, neutral and ground are only couple feet maximum length to the main bonding jumper. Short load side of GFCI neutral to ground, GFCI trips. Where is current coming from to drive this?There is no voltage between N & G if there is no current on either one of them.
With the detection accessory I posted you do have a separate voltage source and circuit is completed by connecting load side N to G.
romex jockey
Senior Member
- Location
- Vermont
- Occupation
- electrician
kwired
Electron manager
- Location
- NE Nebraska
Learned about this long time ago, either in trade mag or on this site, but been having trouble finding any online info about it. Can't seem to find where I got that previous image from.
Did find this
Neutral to ground detection starts about middle and goes most the way to the end of the article.
ramsy
Roger Ruhle dba NoFixNoPay
- Location
- LA basin, CA
- Occupation
- Service Electrician 2020 NEC
February 23 2018 By Lee Teschler said:
Yes, I see Kwired reference it testable. Empirical evidence (Observation) appears to confirm Teschler's interpretation of UL 943 test requirements.
The problem is this can't be observed with typical testers in the field. While low-impedance solenoid testers are commonly used by Qualified Persons to trip a live GFCI when probed H-G, trying to probe N-G fails to trip in the same manner.
Qualified Persons may naturally assume, since their tools don't confirm it, the Retro Encabulator's modial interaction of magneto reluctance and capacitive duractance, or some other BS is being sold by internet-trolling carpet baggers.
Qualified Persons wearing proper PPE would need to employ a shorting probe / wire across device N-G, since few solenoid testers, much less standard multi-meters are designed with internal impedance less than 1.6Ω, per Kwired reference to Teschler and the UL 943 standard.
This is also noteable for most AFCI breakers observed with a similar function. N-G probes trip most AFCI's with high-impedance multi-meters, or just by placing Neutral and Grounding conductor in the same hand, with Hot capped off, and switch leg turned off. Wolfram Alpha lists the resistance of a typical human body as 2300Ω to 201kΩ with dry skin. If the UL 1699 standard for AFCI's has a similar test function to trip N-G, I'd guestimate the trigger-happy impedance would be somewhere in that range or higher.
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