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What is the adjustment factor for a raceway or cable that has 7-9 current carrying conductors?
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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%
What is the current carrying capacity of a 18 awg stranded wire rated to 105 deg c 600 volts with PVC insulation?
The 2005 NEC allows 14 amps for 18 AWG wire in conduit, 18 amps in free air. Solid or stranded does not matter. There is no table that allows more current with higher insulation temperature rating. These values are good only up to 86 deg F ambient temperature, and must be derated according to table 310.16 or 310.17 if the ambient temp is above 86. You must also derate for more than 3 conductors in a raceway. I have not seen a PVC insulated wire rated to 105C. Is there such a thing?
How can we calculate cable size for 800A breaker?
Wire sizing is based on the load that the conductors carry. The breaker is then sized to protect the wire. To get to an amperage the wires are going to have to be paralleled. The calculations are already sized in the electrical code books, CEC and NEC. These are code books used by North America electricians. A 500 MCM conductor with an insulation factor of 90 degrees C is rated at 430 amps. Four 500 MCM conductors paralleled will give you an ampacity of 1720 amps. The breaker will need to have a 500 MCM 4 barrel lug to receive the conductors. The same thing with the load end, it will also need a four barrel 500 MCM lug.
What means RAFT in blast furnace?
It is Raceway Adiabatic Flame Temperature present in the front of tuyears.
Can you run AC and DC cables in the same conduit?
In California and I believe the NEC states " no low voltage can share conduit with high voltage". Also it's not recommend to even run "with" or alongside conduit w/ AC in it. The interference will kill you transmission speed.Answer:The above answer is very true. While Cat5 can intersect with AC wire at 90 degrees to the AC wiring, it should not be run parallel with it, unless it's at least a foot or so away.
How can you know cable size for a given current?
NEC code book table 310.15. Find the current you want to send through the conductor, look up which size conductor can handle that amperage. If you are pulling more than three current carrying conductors (hots and neutrals) in the same pipe you need to derate the listed ampacity of the wire. The percentages that you derate to are listed a couple pages before in the code. 4-6 current carrying conductors in the same raceway i believe is derated to 80% and i can't remember right off the top of my head the others.
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.
Do you derate for a three phase line and load conductors in the same conduit?
Yes, there will be a de-rate applied to this type of installation. In the electrical code book the amperage rating of conductors is for allowable ampacities for not more than three copperconductors in raceway or cable. This is based on an ambient temperature of 30 degrees C. If the ambient temperature of the conductors where the raceway is installed is over 30 degrees C the conductor amperages have to be reduced. Where the number of conductors are from 4 to 6 conductors in a raceway, the conductors amperage has to be reduced by .8
In general conductors from the same circuit in nonparalleled installations are required to be what?
in the same raceway or close proximity
What raceway is designed to extend conductors across a floor without embedding it in the floor are called?
Pancake raceways.
The ampacity of a No. 12 aluminum wire with RHW insulation installed in a raceway that has 19 other wires is?
A #12 copper conductor with an insulation factor of 90 degrees C is rated at 20 amps. A #12 aluminium conductor with an insulation rating of 90 degrees C is rated at 15 amps. These conductors ratings only applies to three conductors in a raceway. To apply the derate to the conductor requires the size of the raceway. From 7 to 24 conductors in a raceway, both aluminium and copper conductor's ratings have to be reduced by .70, so 15 amps x .7 = 10.5 amps and 20 amps x .7 = 14 amps respectively.
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%
The ampacity of a number 12 aluminum wire with rhw insulation installed in a raceway that has 19 other wires is?
A #12 copper conductor with an insulation factor of 90 degrees C is rated at 20 amps. A #12 aluminium conductor with an insulation rating of 90 degrees C is rated at 15 amps. These conductors ratings only applies to three conductors in a raceway. To apply the derate to the conductor requires the size of the raceway. From 7 to 24 conductors in a raceway, both aluminium and copper conductor's ratings have to be reduced by .70, so 15 amps x .7 = 10.5 amps and 20 amps x .7 = 14 amps respectively.
The ampacity of NO 12 aluminum wire with RHW insulation installed in a raceway that has 19 other wires is what?
A #12 copper conductor with an insulation factor of 90 degrees C is rated at 20 amps. A #12 aluminium conductor with an insulation rating of 90 degrees C is rated at 15 amps. These conductors ratings only applies to three conductors in a raceway. To apply the derate to the conductor requires the size of the raceway. From 7 to 24 conductors in a raceway, both aluminium and copper conductor's ratings have to be reduced by .70, so 15 amps x .7 = 10.5 amps and 20 amps x .7 = 14 amps respectively.
You have 3 sets of conduits with 6 500MCM conductors in each one what is your ampacity?
The ampacity of 500 MCM R 90 degree wire is 395 amps. Don't forget to de-rate the wire as there are more that three conductors in a raceway.
What is the purpose of a tone generator and tone probe?
They are used to trace wiring. There may be multiple conductors in a bundle that are unmarked, or perhaps unmarked wires that go to different locations. The tone generator is connected to a pair of conductors (or one conductor and ground), and the probe is used to find the same conductor on the opposite end. The probe is used to look for the conductor that is carrying the tone. In a bundle of conductors, or several conductors in a raceway, the tone may be induced, or "bleed" into other conductors. In this case, the desired wire has the strongest tone. Connecting the generator to one conductor and ground tends to induce the signal into other conductors. Toning a pair, with neither one grounded, is the most selective, making identification more sure.
Five 8 aluminum conductors with THHN insulation are to be routed through a conduit found in a boiler room with an ambient temperature of 75 degree C. What would be the ampacity of each conductor?
#8 aluminum thhn 90 degree wire is rated at 30 amps. Remember to de-rate the wire for more that three conductors in a raceway and the second de-rate for the ambient temperature. Most students miss the de-rate for more that three conductors in a raceway.
