NFS-320/E/C Installation Manual —
P/N 52745:M2 7/1/14
29
UL Power-limited Wiring Requirements
Installation
3.9 UL Power-limited Wiring Requirements
Power-limited and nonpower-limited circuit wiring must remain separated in the cabinet. All
power-limited circuit wiring must remain at least 0.25 inches (6.35 mm) from any nonpower-
limited circuit wiring. All power-limited and nonpower-limited circuit wiring must enter and exit
the cabinet through different knockout and or conduits. To maintain separation, group non-power
limited modules together, i.e., group modules on the same side of the enclosure or in separate rows.
Figure 3.13 shows one configuration that meets these UL requirements. Equipment is configured
with at least a 0.25 inch (6.35 mm) separation between power-limited and nonpower-limited
wiring; AC and battery wiring is routed away from power-limited wiring.
64
0-
2-
PW
R
L
M
T
WI
R-
IS
O2.
w
m
f
Figure 3.13 Typical Wiring for UL Power-limited Wiring Requirements
(Shown with relays as connected to power-limited modules)
NOTE:
AC and battery wiring are not power-limited. Maintain at least 0.25 inches (6.35 mm)
between power-limited and non power-limited circuit wiring. Install tie wraps and adhesive squares
to secure the wiring. Use a power-limited source for relay output on terminals
TB5 and TB4.
See Figure 2.2, “NFS-320 and Power-Supply: Wiring Connections” on page 13 to identify power-
limited and non-powerlimited circuits.
NOTE:
Drawing is not to scale; proportions and angles are exaggerated to show wire-placement
more clearly.
NOTE:
If additional knockouts are added to the backbox, proper separation of power-limited and
nonpower-limited wiring should be maintained.
Power-limited Circuits*
Nonpower-
limited
circuits
To cabinet-mounted batteries
(nonpower-limited)
Power-
limited
circuits
NPL
NPL
Maintain vertical
separation where
circuits appear to
“cross”
