Description
Special-Purpose Ground-Fault Circuit Interrupter (SPGFCI),
Class C and Class D
Industrial Shock Block (ISB) is a personnel protection device
designed to meet the requirements for special-purpose
GFCIs defined by UL 943C. This standard outlines GFCI
classes specifically designed for use in industrial facilities.
Class C GFCIs are intended to be used on three-phase
systems where the line-to-line voltage is 480 V or less with
a trip level of 20 mA, while Class D GFCIs are intended to be
used on 600 V systems. The Industrial Shock Block includes
DFT harmonic filtering, an automatic self-test feature and
is compliant to the UL 1998 Software in Programmable
Components standard.
Ground-Fault Circuit Interrupter (GFCI), Class A
The Shock Block is available as a 208 V Class A GFCI,
allowing commercial kitchens, construction sites, and other
non-dwelling units with wet areas to meet NEC 210.8(B) for
their three-phase loads up to 60 A.
Equipment Ground-Fault Protective Device (EGFPD)
Industrial Shock Block is also available with adjustable
protection settings as an EGFPD. The EGFPD models can be
set to trip at 6 mA or from 10–100 mA in increments of 10
mA. This offers more flexibility since GFCI devices are not
allowed to have an adjustable trip level.
Ratings and Models
Industrial Shock Block (GFCI & EGFPD) is available for threephase
voltages from 208 to 600 V with a maximum full load
current of either 32 or 60 A. The power system can be either
solidly or high-resistance grounded and the load must be
three phase without a neutral.
The standard enclosure is IP 69K/NEMA 4X and outdoor
rated, suitable for all industrial environments including hightemperature
washdown used in food production. A Class
II, Division 2 option is also available for applications where
explosive dust may be present (future option).
Ground Wire (Load-Ground) Monitor
The Industrial Shock Block also monitors the ground wire
(load-ground) connection between the Industrial Shock Block
and load. This is a required feature for Class C and D GFCI
devices and is recommended for Class A GFCI and EGFPD
devices. If the ground-return path is broken, the Industrial
Shock Block will trip and provide an alarm by changing the
state of the alarm contacts. This monitoring circuit includes
an extra wire (pilot wire) between the Industrial Shock
Block and load. At the load, the pilot wire is connected to a
termination device. The other end of the termination device
is connected to the load ground (typically the enclosure).