Standard defining max allowable temperature rise busbars and busbar connections

[GeorgeMech4]

Is there an standard (IEC, IEEE, NETA) defining maximum allowed temperature for connections and busbars connected to LV side of an transformer ?
The only standards i found mentioning temperature rise were like IEC 62271-1 HIGH-VOLTAGE SWITCHGEAR AND CONTROLGEAR and IEC 61439 Low Voltage Electric Switchboards. Are these applicable also for the case that interests me ?

 

[desertfox]

Hi GeordgeMech4

If the busbars are coming from a piece of switchgear then the temperature rise for those busbars would be governed by the standard you mention.Do you have any info on the temp rise for the transformer?

“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein

 

[che12345]

GeorgeMech4 (Mechanical)(OP)22 Jul 24 10:53
"Is there an standard (IEC, IEEE, NETA) defining maximum allowed temperature for connections and busbars connected to LV side of an transformer ?"
I have the following opinion for your consideration.
1. Assumption: conductor is connected on the transformer LV terminal palm. the conductor can be of bare cu/Al, busduct or cable on lug etc...The LV terminal palm is in the open air i.e. IP 00 and cooled by ambient air < 40 [sup]o[/sup] C.
2. In this case, the permissible temperature-rise is limited by the insulation material supporting the connection (see IEC). LV bushing is usually of porcelain (no issue); busduct connection is cu-to-cu or Al- cu (see IEC); where cable is limited by the cable insulation type (PVC or XLPE etc.).
3. Depending on the location of the installation, the local code prevails. Attention: There is NO harmonisation on the temperature-rise limit between IEC and IEEE on bare, tinned or silver plated etc....
Che Kuan Yau (Singapore)

 

[che12345]

GeorgeMech4 (Mechanical)(OP)22 Jul 24 10:53
"Is there an standard (IEC, IEEE, NETA) defining maximum allowed temperature for connections and busbars connected to LV side of an transformer ?"
I would like to suggest the following in addition to my opinion dated 22nd inst., for your consideration.
1. Info: In general, the max allowed temperature based on say 40 [sup]o[/sup] C ambient + temperature-rise 30 K = 70 [sup]o[/sup] C would be fine in compliance with IEC or IEEE for bare cu-cu or cu-Al connections.
2. Proposal: There are " temperature sensitive reversible label" on the market at very low cost. Stick say a 7 temp point 60-90 [sup]o[/sup] C on each connection point. It is easily done on site on new/existing installation. The temperature is read on the spot; avoiding computer interfacing or thermography equipment at a very high price; which needs skill to set the correct e-factor etc...
Che Kuan Yau (Singapore)