POWER SUPPLY AND WIRING
Conduit, Wire and Fuse Sizing
The use of metal conduit with metal conduit connectors is recommended for all electrical connections. Use the
NEC or CEC to determine the required conduit size for the application.
Refer to the chart below for the minimum allowable wire size for each controller. Note that these wire sizes
are not adjusted for voltage drop due to long cable lengths. Refer to the wire sizing chart in the appendix to
determine the maximum length for the input cable. Refer to the motor manual for maximum output cable length.
The maximum recommended voltage drop on both input and output cable combined is 5%. Standard wire
sizing charts give maximum cable lengths for only input or output cables. Because of this the lengths given in the
table must be adjusted so the total voltage drop does not exceed 5%. For example, if the input wire sizing chart
in the appendix gives the maximum length of 400' and only 100' is used then only 25% of the total voltage drop
(1.25% drop) is used. The maximum output cable length read from the motor's wire sizing chart must then be
adjusted to 75% of its value so that the maximum voltage drop of 5% is not exceeded.
Use only fast acting class T fuses. The wire used for the input power connections on models SPD20300 and
SPD20300F must have a temperature rating of 90ºC minimum. All other wire must be rated 75 ºC minimum. The
chart below shows the recommended sizes for wire and fuses for each controller. Note that the wire sizes were
not adjusted for voltage drop due to long cable lengths.
Voltage
Frame Size
1
2
208/230
3
4
1
460
2
3
Full Load
Model Number
Output Current
SPD20050
SPD20050F
SPD20075
SPD20075F
SPD20100
SPD20100F
SPD20150
SPD20150F
SPD20200
SPD20200F
SPD20250
SPD20250F
SPD20300
SPD20300F
SPD40050
SPD40050F
SPD40075
SPD40075F
SPD40100
SPD40100F
SPD40150
SPD40150F
SPD40200
SPD40200F
SPD40250
SPD40250F
SPD40300
SPD40300F
Nominal HP
17.8
5.0
26.4
7.5
37.0
10.0
47.4
15.0
60.6
20.0
76.0
25.0
94.0
30.0
8.9
5.0
13.2
7.5
18.5
10.0
23.7
15.0
30.3
20.0
37.5
25.0
47.0
30.0
Generator
Fuse Size
Size (VA)
30.0
7700
40.0
11400
50.0
16000
70.0
20500
80.0
26200
110.0
32800
135.0
40600
15.0
7700
20.0
11400
30.0
16000
40.0
20500
50.0
26200
60.0
32400
70.0
40600
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