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9
IO-70065
01/2020
ASCO 335 Surge Protective Device (SPD)
Electrical
Branch Circuit Overcurrent
Protection and Disconnect Means
Location of Surge Protective
Device (SPD)
HAZARD OF ELECTRIC SHOCK, EXPLOSION, OR ARC FLASH
• Use conductors rated for the Overcurrent Protection Device (OCPD) per
applicable codes.
• Use conductors rated for the application per applicable codes.
Failure to follow these instructions will result in death or serious injury.
A branch circuit Overcurrent Protection Device (OCPD) either in the form of
a circuit breaker or fuse must be provided for the ASCO 335 Type 2 device.
The branch circuit OCPD should either provide or include a disconnecting
means.
Since the current drawn by the ASCO 335 device during normal operation is
negligible, the ASCO 335 device can be connected to a dedicated, separate
branch circuit or connected to a suitable existing branch circuit.
When connected to a separate, dedicated branch circuit, the OCPD setting
must be selected to protect the conductors feeding the ASCO 335 device
per applicable state and local building codes.
UL 1449 Type 2 SPDs must be installed on the load side of the main Over-
current Protective Device (OCPD). All installations should either provide or
include a disconnecting means.
Locate the SPD as close as possible to the circuit mains being surge-limited
to minimize the wire length and optimize SPD performance. Avoid long wire
runs so that the device will perform as intended. To reduce the impedance
that the wire displays to surge currents, the phase, neutral, and ground
conductors (wye and high-leg delta configurations), or phase and ground
conductors (delta configurations), must be routed within the same conduit
and tightly bundled or twisted together to optimize device performance.
Avoid sharp bends in the conductors. See Figures 2 and 3.
DANGER
