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Specifically designed for motion picture production, Shock Stop GFCIs offer a reliable alternative to
finicky hardware store devices. In fact, since revisions to the 2020 National Electrical Code (NEC) now
require GFCI protection on all outdoor receptacles of 250V or less to ground, 50A or less (Section 210.8(B)(4)),
Shock Stop GFCIs offer the most economical means of providing reliable ground fault protection on location.
Many HMI, Kino, and LED power supplies generate residual currents that will nuisance trip hardware store
GFCIs. The reason is that these residual currents, which consist of high frequency harmonics
generated by the load, are returned to the power source by the system equipment-grounding conductor (EGC).
These trips are a nuisance because the residual currents themselves pose no shock hazard and are therefore
totally unnecessary from a safety standpoint. A second reason hardware store type GFCIs are prone to tripping
with motion picture lights is that they employ a trip curve designed for household appliances and power
tools. Fast acting and with a low trip threshold, hardware store GFCIs will trip immediately when used to
power many motion picture lights with electronic power supplies (HMIs, Kinos, and LEDs).
To prevent nuisance tripping with electronic power supplies, Shock Stop GFCIs employ inverse-time trip delay
and narrow band pass filters to attenuate high frequency harmonic currents. Attenuated by the filter, the
noise generated by electronic power supplies won't cause them to trip. Inverse-time trip delay means they can
withstand switch-on surges. More accommodating trip curves, plus harmonic filtration, equals nuisance
free operation. It's simple math.
Shock Stop GFCIs offer the most economical means of providing reliable ground fault protection when filming on location
Available with 60- and 100A Bates connectors, as well as 400A 3-phase Cam connectors, Shock Stops
can be installed inline after generators and branch circuits. Such tiered ground fault protection
offers many benefits over a blanket approach, especially when it comes to the unusual requirements of
motion picture production. For instance, should a ground fault occur in a blanket system the entire distribution system will go down leaving the crew figuratively "in the dark"
on where the leak occurred while the entire set may be left literally in the dark further inhibiting their ability to get the lights back on. A tiered ground
fault protection system, ensures that only the part of the distribution system affected by a fault will shut down.
To meet the new 2020 Code requirements and avoid nuisance tripping from accumulated residual currents, the Shock Stop 60-100 IL can be used
just upstream of a 100A Lunch Box. To provide ground fault protection for larger lights, while avoiding
nuisance tripping from residual current accumulated over multiple branch circuits downstream, a 400A 3-Phase Shock Stop
with a higher trip threshold can be used upstream closer to the source of power.
Unlike hardware store GFCIs, the 20A Shock Stop 20-15IL will not be overloaded by a M18 HMI or 2k Tungsten light.
Specifically tailored to the type and size loads used in motion picture production, Shock Stops provide reliable ground fault protection for larger
lights, or more smaller lights, than has ever been possible (use this link for a detailed explanation on how to protect your crew from electrical shocks .)
For rental or sales information contact ScreenLight & Grip, Ph: 617-224-8534, email: rentals@screenlightandgrip.com