DP
O
E™
Power System User Manual
Part Number: PN380C
Rectifiers
1
2
3
Feed 1
Feed 2
AC In
N+1 DC Out
Feed 3
Figure 2: Individual AC Feed Wiring Architecture
Each individual AC feed should be protected using a circuit breaker as listed in
Table 4: Recommended
AC Circuit Breaker and Wire Sizes.
Table 4: Recommended AC Circuit Breaker and Wire Sizes
Type of
Feed
Number of
Rectifiers
on an AC
Feed
Part Number
Maximum
Input
Voltage
Maximum
Rated
AC
Current
(A)
Circuit
Breaker
Minimum
value (A)
90° C
Minimum
Wire
Gauge
(AWG) to
use at 30°
C ambient
Individual
AC
Feed
1
DPOEPWRR500 90
7
15
14
DPOEPWRR500 180
3.5
15
14
DPOEPWRR1250
90 17.6 20 12
DPOEPWRR1250
180 8.8 15 14
DC Output Wiring Sizing
There are two main considerations for sizing DC wire, ampacity and voltage drop.
Ampacity
refers to the
safe current-carrying level as specified by U.S.-based organizations such as Underwriters Laboratories
and the National Fire Prevention Association, which publishes the National Electric Code (NEC).
Voltage
drop
is simply the amount of voltage loss in a length of wire due to ohmic resistance of the conductor. DC
wire may be sized for either ampacity or voltage drop depending on branch load loop length and
conductor heating. In general, ampacity considerations will drive wire selection for short loop lengths (less
than 50 feet) and voltage drop will drive wire selection for long loop lengths (greater than 50 feet). The
National Electric Code table 310.16 provides ampacity values for various sizes, bundles, and insulation
temperature rated wire.
4
