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Derating factor depends on ambient temperature & how u r
laying the cable ie., in Air,Duct,Burried.
normally the current carring capacity of a perticular cable
is calculated at 40*c, but if u lay the cable in air then
it includes the temparture around it,if it increases more
the 40*c then the conductor gets heated up by increasing
the resistance in it thus the current carring capacity of a
given cable decreases, so we will derate the cable
The derating factor of induction motor is the ratio of the
calculated output power to the rated power
Wiki User
∙ 12y ago
Wiki User
∙ 9y agoTo derate means to reduce the power of. This would apply, for example, if someone was turning the horsepower down on an engine.
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How many current carrying conductors are allowed in a raceway before derating?
You can put three ccc's in a conduit (any size conduit) before you derate. Keep in mind that for single phase loads (lighting, receptacles) the neutral is also counted as a current carrying conductor. This derating factor does not apply to nipples 24 inches long or less. See NEC Table 310.15(B)(2)(a) for full details on derating regarding ccc's.
What are the causes of derating of cables?
1. We consider cable de-rating factor, because the method of laying of cable either in air, duct or trench, affect the current carrying capacity as dissipation of heat in air is more than in duct or trench. Now the factors that causes derating are 1. ambient temperature (this is the average temperature of the plant). If surrounding temperature is higher than cable temperature at which it is designed then that increase the resistance of cable conductor which decreases the current 2. Number of cables in cable tray either they are touching each other or at a distance. If cables are touching each other, they created dielectric field around them which in case of touching causes interference with one another that causes resistance to increase. 3. No. of cable trays in a tier.
In the UK what cable should you use for a domestic ring main?
The cable usually used is 2.5mm2 three core (live, neutral and earth). In circumstances where the cable runs are long or derating is required due to temperature 4mm2 is used. The ring main is usually protected by a 32A circuit breaker. In older installations a 30A fuse was used.
What is derating factor of battery?
batteries derating factor will change ,depends upon the temperature& cable size which arelinked with batteries bank.
What is current value after derating factor considered?
Once derating factor is considered the size of cable for perticular electrical load increased by the multipling factor.i,e if 2.5MM2 cable is capable to carry 14amp. of current in general then with 40% of derating fator it can carry only 8.4amp.
The calculation used to determine amperage of a conductor based on the total number of conductors in a conduit is called A derating B voltage drop C conduit fill D conductor fill?
derating
What is derating factor in case of diesel engines?
air flow speed
How many current carrying conductors are allowed in a raceway before derating?
You can put three ccc's in a conduit (any size conduit) before you derate. Keep in mind that for single phase loads (lighting, receptacles) the neutral is also counted as a current carrying conductor. This derating factor does not apply to nipples 24 inches long or less. See NEC Table 310.15(B)(2)(a) for full details on derating regarding ccc's.
Definition of derating?
The verb derating means to assess the value of (some types of property, such as agricultural land) at a lower rate than others for local taxation; operation of a machine at less than its rated maximum power in order to prolong its life.
What is the meaning of derating factor?
A transistor rating that tells how much the maximum allowable value of PD decreased for each 1°C rise in ambient temperature.
What is derator?
In electronics, derating a device means using it without turning its power all the way up. People derate electronic devices to make them last longer.
Can you run a 12 amp heater on 125 feet of 12-3 wire?
depending on the insulation type. Most 12 AWG wire will carry that current capacity either. Unless you are running it in the desert or some place extremely hot where derating becomes a factor.
What are the causes of derating of cables?
1. We consider cable de-rating factor, because the method of laying of cable either in air, duct or trench, affect the current carrying capacity as dissipation of heat in air is more than in duct or trench. Now the factors that causes derating are 1. ambient temperature (this is the average temperature of the plant). If surrounding temperature is higher than cable temperature at which it is designed then that increase the resistance of cable conductor which decreases the current 2. Number of cables in cable tray either they are touching each other or at a distance. If cables are touching each other, they created dielectric field around them which in case of touching causes interference with one another that causes resistance to increase. 3. No. of cable trays in a tier.
In the UK what cable should you use for a domestic ring main?
The cable usually used is 2.5mm2 three core (live, neutral and earth). In circumstances where the cable runs are long or derating is required due to temperature 4mm2 is used. The ring main is usually protected by a 32A circuit breaker. In older installations a 30A fuse was used.
If ther are more than conductors in the raceway the ampacity of the conductors must be derated?
Ampacity must be derated depending on the number of conductors and the ambient temperature. In the Canadian Electrical Code Table 5C denotes derating for the number of conductors. 1-3 conductors = 100% load 4-6 conductors = 80% 7-24 conductors = 70% 25-42 conductors = 60% 43 or more conductors = 50%
