Criterion 6.1.5.4 Temperature Rating

Criterion text:
Wiring under insulation shall be rated for expected increased temperature conditions.

Comments:
This criteria applies to sensor wiring placed close to components at high temperatures.

Installers should keep sensor wiring away from direct contact with hot piping.

If wiring is next to collector loop piping, it is better to be adjacent to feed line piping since the return line can get reach temperatures of 160 degrees F. These high temperatures can have a detrimental affect on system wiring and in turn on system operation.

Figure 1 illustrates a potential problem if the sensor wiring is installed in direct contact with the hot return line piping.

Figure 1

The solar industry has developed flashing to accommodate both collector feed and return line piping as well as sensor wiring - and keep them separate. This flashing should be used. (Figure 2)

Figure 2

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