90 degree rated MCBs

I'm still on the quest to fix the design challenges on my theatre project and we are nearly there.

Does anyone know of a manufacturer with a 125A TPN DIN-rail MCB that has terminals rated for 90 degree operation?  The ABB breakers we're using elsewhere do have a 105 degree rating but they don't have 125A available as they re-designed it and are awaiting a new approval.  Most manufacturers don't seem to publish the terminal temperature rating but you can sometimes get it from their tech support if you can get them to respond!

The situation I have will generally have a 90-degree rated cable in trunking with grouping factors applied, and this will terminate on DIN-rail terminals (105 degree rated) at the panels/socket boxes at each end.  These terminals will then connect to the appropriate breakers/connectors via lengths of 105 degree tri-rated cable, over a reasonable length (0.5-1m-ish) inside the breaker panel where there is more fresh air generally.  The designer is however insisting that to be able to use the 90-degree basis for the cables in the trunking then all components right through to the MCB terminals need to be 90 degree rated.

Hence if anyone knows of a 125A TPN MCB with a 90 degree terminal rating then it would be of great assistance as this is the last piece of the puzzle.

Jason.

Parents
  • Probably no immediate help in dealing with someone who is entirely standards driven, but I have found the peak temperature indicating stickers to be a useful thing to have in the armoury in cases of 'how hot is my terminal block' . We tend to fit them inside kit at manufacture so that we can deal with damage / fault claims - if the customer clearly did not or did not keep the fan intake clear or switch it on  while covered over etc.

    I have also used them to justify a position of 'no action required' on some things that ran cooler than everyone thought they did. Left on critical parts and inspected every year or so, if the 'high tide mark' creeps up then you know that the design is being pushed, before it fails in service. If they do not,, it is fine.

    Note that the '40' degree markers will turn black in a trouser pocket on a  hot day, and a car in the summer sun can ruin the whole strip up to about 60 degrees, so storing the stickers carefully is part of the process. I once posted a pack out to a dry sandy country, only to find that they had all been overheated in transit.

    Mike

Reply
  • Probably no immediate help in dealing with someone who is entirely standards driven, but I have found the peak temperature indicating stickers to be a useful thing to have in the armoury in cases of 'how hot is my terminal block' . We tend to fit them inside kit at manufacture so that we can deal with damage / fault claims - if the customer clearly did not or did not keep the fan intake clear or switch it on  while covered over etc.

    I have also used them to justify a position of 'no action required' on some things that ran cooler than everyone thought they did. Left on critical parts and inspected every year or so, if the 'high tide mark' creeps up then you know that the design is being pushed, before it fails in service. If they do not,, it is fine.

    Note that the '40' degree markers will turn black in a trouser pocket on a  hot day, and a car in the summer sun can ruin the whole strip up to about 60 degrees, so storing the stickers carefully is part of the process. I once posted a pack out to a dry sandy country, only to find that they had all been overheated in transit.

    Mike

Children
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