T
T.M.Haja Sahib
Guest
Pretty sure, if the circuit consists of only such devices. If the circuit contains other devices such as starters, contactors etc., your cable can not be used again at its full load capacity.
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T
T.M.Haja Sahib
Guest
'Comparison of ANSI/NEMA and IEC requirements for low voltage motor control center' by Carlos A.Sepuveda and Gustavo Salloum.S
Ummm............
Telemec type D contactors are good for 110C.
The following comment is from Siemens based on IEC 60947-4-2.
Materials and Temperature-rise limits of the main terminals of soft starters 3RW:
3RW301: Cu bare -> 60 K
3RW302: CuZn -> 65 K
3RW303. Cu bare -> 60 K
3RW304: Cu bare -> 60 K
3RW312: CuZn -> 65 K
3RW34: Cu with Sn-plating -> 65 K
3RW402: Cu with Ag-plating -> 70 K
3RW403: Cu bare -> 60 K
3RW404: Cu bare -> 60 K
3RW442: Cu with Ag-plating -> 70 K
3RW443: Cu with Ag-plating -> 70 K
3RW444: Cu with Ag-plating -> 70 K
3RW445: Cu with Sn-plating -> 65 K
So, from a 40C enclosure temperature which is fairly typical for industrial applications, bare copper terminals would be good for 100C and plated up to about 110C which coincidentally coincides with that of the Telemec contactor.
Therefore, may I further beseech the great and good Maharaja to bestow the blessing of his greatness on his most humble servant, (i.e. yours truly) in permitting the use of XPLE at its full rating on such terminals with a permissible surface of 100 ?C or greater?
Which includes ALL of the above listed.
T
T.M.Haja Sahib
Guest
By 90C cable it is meant not the total temperature of the cable conductor but the temperature rise of the cable conductor over the ambient.
I hope I am not your Maharaja, just an acquaintance over the web.
I hope your mind is now clear.
I hope I am not your Maharaja, just an acquaintance over the web.
I hope your mind is now clear.
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- Location
- Massachusetts
Sorry that is incorrect
Conductor temp ratings are max temps not rise temps.
At least for cables to be used under the NEC.
T
T.M.Haja Sahib
Guest
Yes.
I am not correct.
Thanks for correction.
Still it is not permissible to use 90C cable at its 90C rating in the case presented by Bes at post #23.
See also post#22
What do you think?
I am not correct.
Thanks for correction.
Still it is not permissible to use 90C cable at its 90C rating in the case presented by Bes at post #23.
See also post#22
What do you think?
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- Massachusetts
What I think is without knowing the specifications of the terminations, equipment and the codes that apply for that area is it is impossible to say one way or another.
T
T.M.Haja Sahib
Guest
The web link for post #22 is below and pertinent information is on page no.2
www.labplan.ufsc.br/congressos/td2006/papers/td06_398.pdf
www.labplan.ufsc.br/congressos/td2006/papers/td06_398.pdf
And for BS7671.
Current carrying capacity tables, for example Table 4E4A:
"Conductor operating temperature 90C."
T
T.M.Haja Sahib
Guest
The moral of this thread is never use 90C cable at its 90C rating on impulse, unless specifically stated in the application manuals for other applications.
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Care to explain why?
K8MHZ
Senior Member
- Occupation
- Electrician
Here in the US if we are terminating to a Cutler Hammer CH breaker we must use the 75 degree column for OCPD selection.
So, If I am using Type Z, 150C conductor, the NEC allows for a 43 amp ampacity at 150C. But, If I am connecting to the above breaker, I have to protect it for the ampacity shown in the 75 degree column, or 25 amps.
Now when we have to de rate, that is where there is an advantage to the 150C conductors. If I have 11 conductors in a conduit I have to de rate to 50 percent. If I am using THHW, I have to start my de rating at 75 degrees. So, I would have to use 8AWG to connect to a 20 amp breaker.
If I am using Type Z, I get to start at 150 and so long as the final rating is consistent with the rating of the terminal, we don't have to change size. Since 50 percent of 43 amps is over 20, we can use 12AWG conductors with a 20 amp OCPD.
I have never seen a connector rated for 150C, but they likely exist.
But 400V 50Hz isn't in the US
- Location
- Massachusetts
K8MHZ
Senior Member
- Occupation
- Electrician
Oh, so kick us off the bloody planet then.
Thread title: Termination temperatures around the globe
:lol:
- Location
- Massachusetts
Yes, that I know.Well not from the utility but it is here.
Much like we have 60Hz here. We need frequency converters. We have one in our test bay to test kit we make for the US market.
Not so much to test. Rather to demonstrate correct operation on a 60Hz supply.
Chill....
This topic was taken from a question about cable sizes for a 550kVA 400V genny.
Not a likely US spec.
Gar, a respected member, most reasonably, suggested European cable sizes.
I suggested an alternative.
The Maharaja waded in with reasons why my alternative wasn't viable and knocked the topic off course.
Happens.
- Location
- Massachusetts
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
The Issue here is the understanding of how a terminal dissipates heat through the conductor in a safe and effective manner, a terminal that is rated 75?c will have less mass then a terminal rated at 150?c, thus it depends upon the conductor to heat sink some of the heat and the reason for sizing conductors based upon the rating of the terminal for a given amount of current.
For the above reason we can understand why conductor sizing is based on the terminal temp rating.
At least I hope we can:blink:
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