NEC 110.14(C)(2) Separate Connector Provisions

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ron

ron

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Does this section allow the use of 90 deg wire ampacities if the termination lugs on both ends are rated at 90 degrees and they land on "run backs" bus bar in UL 1558 SWGR (one end) and bus bar in a generator terminal enclosure (other end)?
 
Unless he manufactures instructions tell you different and all terminals in the circuit are rated @ 90 deg C. and you select a conductor from the 90 Deg C. coulomb, I do not see there being a problem
 
Even if the conductors and terminals were rated for 90? C you would still need 90? C listed equipment.
 
ron said:
Since SWGR often doesn't have temperature ratings writen on the enclosure or breaker (because the wire doesn't terminate on the breaker), it seems that it would be ok.
Click to expand...

You might be correct, but how would you know for sure?
 
infinity said:
You might be correct, but how would you know for sure?
Click to expand...
I posed the question to the manufacturer and we'll see.

It could mean 10-12% less copper, and we are dealing with miles and miles (20 paralleled sets per feeder) of copper, so it is worth chasing down. Underground conduit banks gets derated pretty severely.
 
infinity said:
You might be correct, but how would you know for sure?
Click to expand...

I would agree the equipment termination on the bus pads would need to be rated according to its ambient temperature that it is installed in.

Siemens has been asked about the limitations on
temperature for user?s cable connections to switchgear for
many years. ANSI/IEEE C37.20.2 (for metal-clad switchgear)
and ANSI/IEEE C37.20.3 (for metal-enclosed interrupter
switchgear) indicate that the temperature in the cable
termination compartment should not exceed 65 ?C when
the equipment is operating at its full continuous current
rating with the switchgear in a location with an ambient of
40 ?C. In ANSI/IEEE C37.20.2-1999, this temperature limit
inside the cable connection compartment is indicated in
clause 5.5.5, excerpted below:
5.5.5 Temperature limitations for air surrounding
insulated power cables
The temperature of the air surrounding insulated cables
within any compartment of an enclosed assembly shall
not exceed 65 ?C when the assembly is
a)


Eq
uipped with devices having maximum current rating
for which the assembly is designed.
b)


Car
rying rated continuous current at rated voltage and
rated power frequency.
c)


In an ambient air t
emperature of 40 ?C.
NOTE ? This temperature limitation is based on the use
of 90 ?C insulated power cables. Use of lower temperature
rated cables requires special consideration.
This has caused some users concern because this would
suggest that cable ampacity must be adjusted downward
due to excess temperature. We think this is not necessary in
most cases.
 
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