Conductor Ampacities

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Ingenieur

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110.40 termination limitations
based on tables 310.60(C) (67 thru (86)
ref 310.60(C)(67) for allowable ampacities (hence termination amps)
a note says refer to 310.60(C)(4) for temp adjustments

Using (67) for example only
so for example a 2001-5000 vac #2 cable is good for 160
if ambient is <10 then 1.26 x 160 = 202
and the 90 degree terminations are acceptable

same applies to the cable

bear in mind that although ampacity is increased operating temp is not
still 90
 
I

Ingenieur

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Summary
required 1.25 x 166 = 208

nec 2011

rated 154A at 40C with 105C insul table 310.60.C.71 (2001-5000V 105C) and mfgs data
adjusted per 310.60.C.4 26-30 = 1.07 x 154 = 165

termination allowable 310.60.C.67 2001-5000 105C=175 A with no adjustment
but it does appear that an adjustent is allowed by the foot note
With adjustment 1.07 x 175 = 187 A
either way 175 or 187 > 165 so ok

but 165 < 208
cable too small
 
Smart $

Smart $

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Ingenieur said:
...
termination allowable 310.60.C.67 2001-5000 105C=175 A with no adjustment
but it does appear that an adjustent is allowed by the foot note
...
Click to expand...
110.40 says you must use 90°C...
110.40 Temperature Limitations at Terminations. Conductors
shall be permitted to be terminated based on the
90°C (194°F) temperature rating and ampacity as given
in Table 310.67 through Table 310.86, unless otherwise
identified.
Click to expand...
...and I'm doubtful you find terminals that are identified as higher and so marked, but I'll accept evidence to the contrary. :happyyes:
 
I

Ingenieur

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Smart $ said:
110.40 says you must use 90°C...

...and I'm doubtful you find terminals that are identified as higher and so marked, but I'll accept evidence to the contrary. :happyyes:
Click to expand...

if they make a 105C cable they make terminations
if not why make a more expensive cable when it is limited to 90 by available terminations?
 
Smart $

Smart $

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Ingenieur said:
if they make a 105C cable they make terminations
if not why make a more expensive cable when it is limited to 90 by available terminations?
Click to expand...
Same reason they make 90°C-rated LV wire and only have 75°C-rated terminations in listed equipment. (That amounts to IDK :D)

Yes they make 90°C-rated terminations, and you can build your own transition cabinet to get it up to 90°C ampacity... but that is going above what electrical trade persons consider the norm.
 
I

Ingenieur

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Smart $ said:
Same reason they make 90°C-rated LV wire and only have 75°C-rated terminations in listed equipment. (That amounts to IDK :D)

Yes they make 90°C-rated terminations, and you can build your own transition cabinet to get it up to 90°C ampacity... but that is going above what electrical trade persons consider the norm.
Click to expand...

Burndy makes 100's of 105C connectors
 
Smart $

Smart $

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Ingenieur said:
Burndy makes 100's of 105C connectors
Click to expand...
Yes, but the equipment to which those connectors are terminated must be listed for 105°C operation, as it is not just the terminations themselves that has to be rated rated for 105°C. Some have said on here that no equipment is listed above 75°C... but I believe that is only LV equipment. MV equipment should at least be listed at 90°C (switchgear, transformers, and such). If you know of any that are listed for other temperature terminations, please enlighten us...
:)
 
I

Ingenieur

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Smart $ said:
Yes, but the equipment to which those connectors are terminated must be listed for 105°C operation, as it is not just the terminations themselves that has to be rated rated for 105°C. Some have said on here that no equipment is listed above 75°C... but I believe that is only LV equipment. MV equipment should at least be listed at 90°C (switchgear, transformers, and such). If you know of any that are listed for other temperature terminations, please enlighten us...
:)
Click to expand...

they are
ANSI and UL
 
I

Ingenieur

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iwire said:
If by accurate you mean it hurts your credibility I agree.
Click to expand...

not mine
not that I seek chat room credibility lol

it's going to be a real problem since MV-90 cable is being phased out and MV-105 is already in widespread use and is being designed at rated capacity lol
in fact all MV-105 cable I've seen was actually TERMINATED and had power flowing thru it

bus bar...in ambient 40C what is the allowable temp rise? and what is the sum of amb + rise?
 
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