Download Effects of smart meter RF on GFCI units

Caroline Storm
Sponsored by: Dr. David Wetz, Simon Donahue
Introduction to GFCIs
Introduction to Smart Meters
Introduction to GFCIs
The Problem
 Construction sites power lines are exposed to the
weather , for safety they have GFCIs on the line
 The GFCIs are installed close to the Smart Meters
 Due to the proximity the GFCIs are tripping
Hypothesis
 The RF created magnetic field is causing the differential
transformer to detect extra current on the hot side relative
to the neutral side
 Where does the interference originate?
 Magnetic coupling on the hot line
 Magnetic coupling with the differential transformer
 RF transmission being picked by internal wiring in the smart
meter
 Magnetic field effecting the solenoid
Discoveries thus far
 Two identical GFCIs,
except the material used
for the hot line
 When copper is used for
the hot line, GFCI does
not trip
 Covering the hot line in
copper also keeps the
GFCI from tripping
Discoveries thus far
 Eaton’s studies found
that placing ferrite beads
on the lines between the
GFCIs and the Meter
solves the problem
 However, connecting the
GFCIs to a separate
power supply has no
effect
Inferences
 Direct interaction with differential transformer or RF
transmission in the internal wiring are not the cause
 Most likely the faulty tripping is caused by magnetic
coupling with the hot line or the hot conductor in the
GFCI
Further avenues to explore
 What is the strength of the magnetic field coming
directly off the wire
 Does the placing of the ferrite bead affect the impact
of the ferrite bead on the fault
 What is the threshold voltage of at which the
differential transformers sends the trip signal
Questions?