0
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.
Wiki User
∙ 11y ago
Add your answer:
Earn +20 pts
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 fire on MCB?
loose screws or corroded cables or over current above breakers rating (faulty breaker not tripping when meant to) internal fault with breaker.
What is the derating?
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
Why are electrical cables set to sag?
because of heat cables expand
Single core cables benefits?
One of the single core cables benefits is high current rating. The other benefit is that the operating temperatures of single core cables are least affected by the other cables.
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.
What causes the sound out of the speakers to crackle?
Not always, but often, interconnects, or another word for them, cables.
What causes humming at PA system?
It could be... Signal cables crossing electrical cables , bad earthing on the equipment , a signal loop eg feedback , static , intaferance ( due to poorly shielded cables ) or a bad connection
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.
How is energy lost from power stations to homes?
The resistance of the cables that conduct the electric current away from the substations causes the cables to dissipate some of the electrical energy in the form of heat.
What causes a 2000 ford escort zx2 that has fire not to crank?
Bad battery, starter, cables or switch.
What condition causes data to arrive out of sync in longer IEEE 1284 cables?
A delay causes data to arrive out of sync in longer IEEE 1284 cables. This is due to the late measurements of the clock signal, which results from the time-consuming travel down a long IEEE cable.
What does it mean if you hear repetative clicking when you try to start your truck?
Causes include a weak battery, loose cables, failed starter.
