Table 310.16 and 90 Deg Temps
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joebell
Senior Member
- Location
- New Hampshire
Re: Table 310.16 and 90 Deg Temps
The 90 degree colum in table 310.16 I know is used foradjustment factors such as derating and temperature correction but I don't know of any other instances in which you would use it , most terminations are only listed for 75 degrees
The 90 degree colum in table 310.16 I know is used foradjustment factors such as derating and temperature correction but I don't know of any other instances in which you would use it , most terminations are only listed for 75 degrees
jim sutton
Senior Member
Re: Table 310.16 and 90 Deg Temps
Correct me if I'm wrong, but 110.14(C)(1)(a)(3) and 110.14(C)(1)(b)(2) allow the 90deg column if the equipment is listed and identified for the use of 90 deg conductors.
Correct me if I'm wrong, but 110.14(C)(1)(a)(3) and 110.14(C)(1)(b)(2) allow the 90deg column if the equipment is listed and identified for the use of 90 deg conductors.
joebell
Senior Member
- Location
- New Hampshire
Re: Table 310.16 and 90 Deg Temps
I would agree Jim, but I don't beleive the testing companies list a termination for 90 degrees do they?
I would agree Jim, but I don't beleive the testing companies list a termination for 90 degrees do they?
charlie
Senior Member
- Location
- Indianapolis
Re: Table 310.16 and 90 Deg Temps
You need to take a look at this thread to get a lot of good information on the subject.
You need to take a look at this thread to get a lot of good information on the subject.
Re: Table 310.16 and 90 Deg Temps
The reason for derating Al9CU lugs to 75 degrees Celsius for factory installed lugs are as follows:
1. Equipment, particularly thermal magnetic circuit breakers, cannot withstand the extra heat. An exception would be certain industrial circuit breaker and equipment.
2. Phase tagging tape is only rated 80 degrees Celsius under U.S. rules.
3. When most people build heavy circuits in copper they only have 3/4 of the wire strands conducting when the equipment is new.
4. There is still a lot of wire out there that is only rated 75 degrees Celsius in a wet environment. I also recently ran into a spool of #8 or #6 Thwn that was only rated 60 degrees Celsius when submerged in water such as in an underground conduit.
5. Copper expands and contracts at a different rate than tin plated aluminum lugs.
6. To get a genuine 90 degree Celsius rating you really need to crimp or weld the connection.
7. Binding screws have more than their fair share of termination resistance.
8. The cooler that a circuit runs the less electricity lost in heating the wires and the circuit lives longer.
The reason for derating Al9CU lugs to 75 degrees Celsius for factory installed lugs are as follows:
1. Equipment, particularly thermal magnetic circuit breakers, cannot withstand the extra heat. An exception would be certain industrial circuit breaker and equipment.
2. Phase tagging tape is only rated 80 degrees Celsius under U.S. rules.
3. When most people build heavy circuits in copper they only have 3/4 of the wire strands conducting when the equipment is new.
4. There is still a lot of wire out there that is only rated 75 degrees Celsius in a wet environment. I also recently ran into a spool of #8 or #6 Thwn that was only rated 60 degrees Celsius when submerged in water such as in an underground conduit.
5. Copper expands and contracts at a different rate than tin plated aluminum lugs.
6. To get a genuine 90 degree Celsius rating you really need to crimp or weld the connection.
7. Binding screws have more than their fair share of termination resistance.
8. The cooler that a circuit runs the less electricity lost in heating the wires and the circuit lives longer.
john m. caloggero
Senior Member
Re: Table 310.16 and 90 Deg Temps
Medium and high voltage equipment is the only equipment that I know of that is listed for use with 90 degree C conductors at the 90 degree C ampacity. This is allowed because the clearance requirements between the live terminals and grounded surfaces is greater than the lower voltage equipment. Therefore there is more air space for dissipation of heat from the higher current on the conductor.
Medium and high voltage equipment is the only equipment that I know of that is listed for use with 90 degree C conductors at the 90 degree C ampacity. This is allowed because the clearance requirements between the live terminals and grounded surfaces is greater than the lower voltage equipment. Therefore there is more air space for dissipation of heat from the higher current on the conductor.
Re: Table 310.16 and 90 Deg Temps
410.33 Branch Circuit Conductors and Ballest.Branch circuit conductors within 3 inches of a ballest shall have an insulation temperature rating of not lower than 90 degree (194 f) unless supplying a luminaire listed and marked as suitable for a different insulation temerature.
This was a question on my journeymans test.I am thinking this is one of the reasons that they have a 90 degree chart . I hope they never make a 90 degree lug or breaker because I wouldn't think that would be an exceptable operating condition for the equipment and the people who have to work and maintain electrical instalations.
410.33 Branch Circuit Conductors and Ballest.Branch circuit conductors within 3 inches of a ballest shall have an insulation temperature rating of not lower than 90 degree (194 f) unless supplying a luminaire listed and marked as suitable for a different insulation temerature.
This was a question on my journeymans test.I am thinking this is one of the reasons that they have a 90 degree chart . I hope they never make a 90 degree lug or breaker because I wouldn't think that would be an exceptable operating condition for the equipment and the people who have to work and maintain electrical instalations.
charlie
Senior Member
- Location
- Indianapolis
Re: Table 310.16 and 90 Deg Temps
Actually, they do make a lot of 90?C connectors but they normally can't be used because of the equipment they are close to.
Actually, they do make a lot of 90?C connectors but they normally can't be used because of the equipment they are close to.
john m. caloggero
Senior Member
Re: Table 310.16 and 90 Deg Temps
The higher temperature rated conductor insulation is to allow the use of the conductors in a high ambient temperature, either due to weather environment or temperature rise in close proximity to heat generating equipment. Ballasts, recessed lamp heat, and heaters are good examples.
The higher temperature rated conductor insulation is to allow the use of the conductors in a high ambient temperature, either due to weather environment or temperature rise in close proximity to heat generating equipment. Ballasts, recessed lamp heat, and heaters are good examples.
luke warmwater
Senior Member
Re: Table 310.16 and 90 Deg Temps
Re: Table 310.16 and 90 Deg Temps
The labels that I have seen on the Scotch colored tape that I can buy at the supply houses around here are UL listed for 80 Celsius.
Also, the cheaper black insulating tapes including some the 3M makes are only listed for 80 Celsius.
Some Arrow Hart and Leviton locking receptacles and electric dryer and stove receptacles have 90 degree Celsius terminals but that is a matter that the boxes might be in an insulated wall. What that means is that the box really can only dissipate heat out the front.
The labels that I have seen on the Scotch colored tape that I can buy at the supply houses around here are UL listed for 80 Celsius.
Also, the cheaper black insulating tapes including some the 3M makes are only listed for 80 Celsius.
Some Arrow Hart and Leviton locking receptacles and electric dryer and stove receptacles have 90 degree Celsius terminals but that is a matter that the boxes might be in an insulated wall. What that means is that the box really can only dissipate heat out the front.
Re: Table 310.16 and 90 Deg Temps
If you do not clean all of the wire strands of copper wire some of the strands will not conduct because of naturally present copper oxide. I have seen more in the way of copper wiring termination failures than aluminum failures. Thanks to catalytic converters copper wiring that is out of door oxidizes just as fast as aluminum.
I have had some instances where copper oxidation has caused an outdoor light fixture on 120 volts to just simply stop working. All that it took to get the fixture to work was to clean up the wires and resplice.
Cleaning all of the wire strands of copper wire with silicon carbide abrasive paper and then treating with anitoxidant does make a big difference as to how hot the connection runs. There is a reson why there are 2 anitoxidants on the market that are formulated for use ONLY with copper wire and brass conduit threads.
The only way that the Chamberlin-Harding 345 KV transmission could have sagged into trees on 14 August 2003 was if 1/2 the wire strands were conducting. At the time that the line sagged into the trees the line was only carrying 44% of its rated capacity. Theoretically, the conductor heating was only 20% of maximum. Photos on television showed that the line had permanently sagged to about 20 feet from the ground indicating that the steel support core had been toasted.
If you do not clean all of the wire strands of copper wire some of the strands will not conduct because of naturally present copper oxide. I have seen more in the way of copper wiring termination failures than aluminum failures. Thanks to catalytic converters copper wiring that is out of door oxidizes just as fast as aluminum.
I have had some instances where copper oxidation has caused an outdoor light fixture on 120 volts to just simply stop working. All that it took to get the fixture to work was to clean up the wires and resplice.
Cleaning all of the wire strands of copper wire with silicon carbide abrasive paper and then treating with anitoxidant does make a big difference as to how hot the connection runs. There is a reson why there are 2 anitoxidants on the market that are formulated for use ONLY with copper wire and brass conduit threads.
The only way that the Chamberlin-Harding 345 KV transmission could have sagged into trees on 14 August 2003 was if 1/2 the wire strands were conducting. At the time that the line sagged into the trees the line was only carrying 44% of its rated capacity. Theoretically, the conductor heating was only 20% of maximum. Photos on television showed that the line had permanently sagged to about 20 feet from the ground indicating that the steel support core had been toasted.
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