415V Molded Case Breaker rated for 80 deg C

[krisys]

Good day!

I have a query on 415V Molded Case Circuit Breaker (MCCB) for the higher ambient temperature application.

Normally, the MCCBs are specified at 40°C. If I need to apply this MCCB for the higher temperature I select with higher rated current and then de-rate it to apply for higher ambient temperature.

Now in one of the projects, my client is demanding the MCCB with rated ambient temperature of 80°C. He says he has procured the MCCB rated 80°C in the previous occasions. I would like to know whether the MCCB with rated ambient temperature of 80°C is available in the market?

My reference standard is essentially IEC. The MCCB is part of an outdoor distribution board (DB) installed in a harsh environmental condition. The DB is having IP-66 enclosure.

Your inputs are highly appreciated.

 

[jraef]

Most of the big name breaker manufactures will have a technical section in their catalogs that tell you how this is done. I know for sure that Siemens does, I can't imagine that Schneider and ABB do not also. They are the people to ask. I will say however that it is generally done as a special order so for one-off breakers, expect to pay a hefty premium and wait a while for it. Yes it involves over sizing the breaker, then calibrating the trip units for the current rating you need, but it also requires different lugs (often copper or bronze), because standard aluminum lugs are usually never rated above 75C.

PS: As I thought about this more, I realized that I've never seen a breaker de-rated for operation at above 70C, so I'm not sure if 80C is attainable.


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