Syn-Tech Systems FuelMaster FMU-2500 Classic Installation Manual page 43

Conduit Requirements
All wires and cables used by the FuelMaster
approved by, and installed in accordance with, the National Electric Codes (NEC), NFPA 70. This is
a common requirement among reputable manufacturers of fuel management systems.
If it is not possible to comply with the requirement for rigid metal conduit, contact Syn-Tech Systems.
Acceptable workarounds may be available.
Conduit Size
. The recommended conduit size is 3/4 inch. Wire sizes and quantities permitting, a
limited number of 1/2 inch conduit may be used. The FMU pedestal bulkhead can accept up to ten
3/4-inch conduits and four 1/2-inch conduits. Larger and smaller conduit may be adapted to fit the
FMU pedestal bulkhead.
The number of required conduit will be dependent upon the application, and the number of connected
Satellite FMUs, EIUs, fuel dispensers, and options. If the number of conductors exceeds the conduit
fill capacity, additional conduit must be used.
Conduit Fill Capacity
If the conduit terminates in a seal-off, seal-offs cannot exceed 25% fill capacity. Table 1 shows the
available area within different size rigid metal conduit at full, 40%, and 25% capacity. Table 2 shows
the cross sectional area of different wire sizes used with an FMU or EIU installation. You can
estimate the NEC requirement by adding the cross sectional area of all the wires you intend to pull
through a conduit, then comparing it to the maximum (40% or 25%) fill capacity of the conduit being
used. If you are exceeding the fill capacity, additional or larger conduit will be necessary.
Table 3-2. Typical Wire/Cable Cross Sectional Area
FuelMaster
®
. The NEC states conduit will not be filled to greater than 40% fill capacity.
Total
Conduit Inside
Size Area
1/2 0.314
3/4 0.549
1 0.887
1-1/4 1.526
1-1/2 2.071
2 3.408
Table 3-1. Rigid Metal Conduit Fill Capacity
Wire/Cable
18 AWG TFFN
16 AWG TFFN
14 AWG THHN
12 AWG THHN
10 AWG THHN
Belden 8723
Belden 5541P1
Belden 9552
Installation Manual
equipment must be routed through rigid metal conduit
®
40%
Area
0.1256
0.2196
0.3548
0.6104
0.8284
1.3632
Diameter
0.0841
0.096
0.111
0.130
0.164
0.160
0.239
0.368
41
25%
Area
0.0785
0.1373
0.2218
0.3815
0.5178
0.8520
Area
0.0055
0.0072
0.0097
0.0133
0.0211
0.0201
0.0449
0.1064