What is derating factor of cable?
The derating factor is applied to reduce the cable’s current carrying capacity. For example, if a X-90 cable can carry 40A @90 degrees, there may be additional factors which requires the cable to be de-rated such that it carries only 30A@90 degrees in the installation.
How is cable derating factor calculated?
One is laying depth, the second is the soil temperature and the third is soil resistivity. Total derating factor = 0.95*0.9*0.91 =0.77, Then multiply this value by the cable current. The resulted current should be the current carrying capacity for the cable.
Is standard for cable derating factor?
IEC 60502 is an International Electrotechnical Commission standard, which gives current ratings for medium voltage cables. Derating factors considered are the ambient temperature, depth of laying and soil thermal resistivity for buried cables, and the grouping of cables. …
What table is used when derating cable for more than 3 hot conductors?
Table 310.15
Table 310.15(C)(1) requires conductors to be derated whenever more than three current-carrying conductors are installed together in a raceway, cable, or in a covered ditch in the earth.
What is correction factor in cable sizing?
A correction factor is a multiplier that is calculated and used to adjust the amount of energy pushed through a cable based on the amount of heat that is radiated when the cable is conducting energy.
What is the purpose of derating factor?
In electronics, derating (or de-rating) is the operation of a device at less than its rated maximum capability in order to prolong its life. Typical examples include operation below the maximum power rating, current rating, or voltage rating.
What is derate factor?
The photovoltaic (PV) derating factor is a scaling factor that HOMER applies to the PV array power output to account for reduced output in real-world operating conditions compared to the conditions under which the PV panel was rated.
How do you derate a cable?
Multiply the conductor’s ampacity by the derating percentage. For example: The 12 gauge wire TW wire in the 52 C attic is derated to 76 percent of its maximum ampacity; 25 amperes x . 82 = 19 amperes. Protect the wire with a circuit breaker rated at 19 amps or less.
How much does it cost to derate?
The recommended value is 80% for fixed resistors and 75% for variable resistors. The values at different temperatures are provided by the derating curves. The process follows standards and guidelines from the derating curves provided by the manufacturer, the military, or other regulatory agencies.
How do you use derating factor?
Multiply the conductor’s ampacity by the derating percentage. For example: The 12 gauge wire TW wire in the 52 C attic is derated to 76 percent of its maximum ampacity; 25 amperes x . 82 = 19 amperes.