GFI Problems in Beauty Parlor

[flashlight]

I have to jump in here and say that hairdryers do not have GFCI's as we know them...


Try placing either the clippers OR the hairdryers on the surge strip, and put the other straight into the receptacle. I'm willing to bet that will solve the problem.

The way they are setup now the clippers are all on the surge strip. However, it is mounted underneath a shelf and low to the ground, so I could not get a good look at it during initial call-- maybe it is simply a power strip with no surge protection features. Will check all this out next week. Thanks for info about "immersion protection," did not know that.

 

[ELA]

I have to jump in here and say that hairdryers do not have GFCI's as we know them.

They have an "Immersion cutoff" device which is supposed to cut the power if the hair dryer falls into liquid. Most hairdryers of that kind have a two-prong plug (which is the first clue that it's not a GFCI) and the power cord's third wire (which would be an egc normally) or shield wire is the immersion devices' "sense" line. ANY sensed voltage (above whatever threshold the device is designed for) will trip the IC device. It DOES NOT look at current imbalance at all.

I believe some have IDCI's and some have GFCI's. Either way they can be sensitive to noise, perhaps one more than the other.
For more on IDCI:

http://books.google.com/books?id=nZzOAsroBIEC&pg=PT2283&lpg=PT2283&dq=IDCI+%2B+immersion+detection&source=bl&ots=by4J4vSK1M&sig=D7DMHa4uu25R1Lm-JSyRVjIc-qA&hl=en&ei=M46GS8W0HYnUM_SFkaMM&sa=X&oi=book_result&ct=result&resnum=4&ved=0CA4Q6AEwAzgK#v=onepage&q=IDCI%20%2B%20immersion%20detection&f=false

 

[ramsy]

you ..suggest ..a neutral to ground voltage might ..cause ..tripping
..there was no functional use of the EGC relative to the GFCI operation.

No EGC sensing is required for GFCI's to sense current imbalance across neutral.

In post #9, Ohms law was used to show "current passes thru GFCI (N-G)". Problem solved.

Must proper tribute be so painful? If nobody else has explained this, perhaps a few of those icons that bow would be in order.

 

[mtnelect]

"GFCI" & "AFCI" - Phantom Tripping

"GFCI" & "AFCI" - Phantom Tripping

Check out my recent post ... it might help !

Mountain Electric Company
Michael E. Olson
Since 1976

 

[ramsy]

Example: Multi Wire Branch Circuit (MWBC)

Found it here.

 

[gar]

100306-1719 EST

ramsy:

I really do not understand your #9 and #23 posts.

If I put 1,000 V between the neutral and the EGC terminals on a Leviton 7899 GFCI device this will not trip the GFCI. Note: because there is a voltage difference between neutral and the EGC does not mean there is any current flow. If there was current flow you would need to define if it was to the input or output side of the GFCI.

If I have zero volts between the neutral and the EGC and I unbalance the GFCI output current by a minimum of approximately 5 MA between hot and neutral on the 7899, then it will trip. The output side means either the receptacle sockets or the output terminals.

What is a simple way to create this unbalance? Simply the internal method used in the GFCI for testing.

I suggest you buy a Leviton 7899, experiment with it, take it apart, and study the circuit and the mechanical mechanism.

.

 

[ramsy]

I do not understand your post..

After finding a few appliances tripping GFCI's lately, which Megger-tested below 1-MegaOhm to ground, and perhaps measuring receptacle continuity (N-G), I must have forgot this (N-G) continuity was a function of the building wiring, main-bonding jumper, not the GFCI.

My fault. Post #5 only applies in cases where a defective device that plugs into the receptacle has shorted the path (N-G), and imbalance is sensed by the GFCI.