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  1. RLebel

    80% rated breakers

    We agree the manufacturer is not responsible for the application. My original question was could a breaker shipped directly from the manufacturer be set at a value which could damage itself? Based on your posts the answer is yes, but it is the designer's responsibility to adjust it to a safe...
  2. RLebel

    80% rated breakers

    I don't challenge the rules, I challenge the fact that a breaker manufacturer would provide a breaker rated at 80% with a trip unit rated at 100%. If the trip unit should not be set at the maximum level, as a minimum, the manufacturer should provide restrictions with the breaker. Is the 134%...
  3. RLebel

    80% rated breakers

    davidbeach - I understand that the breaker can safely operate at 100% for <3 hours, but what is to prevent it from running at 100% indefinitely? Could it be damaged by the additional heat being generated? rhatcher - The 80% breakers are tested at 100% in free air, however when they are...
  4. RLebel

    80% rated breakers

    rhatcher, no offense taken. Your posts help me, if nothing else, it reassures me that I am not the only one who has a hard time understanding their definition of an 80% rated breaker. Logically I think we are on the same page. Logic would dictate that a breaker manufacturer would not allow a...
  5. RLebel

    80% rated breakers

    PS I should probably have specified in my previous post: the breakers provided are 80% rated, the trip unit provided by Schneider for the 80% rated breakers are the 100% rated electronic trip units. They do not have an 80% rated trip unit (or so I am told by their technical support) RHatcher if...
  6. RLebel

    80% rated breakers

    Where did you get this information from? The same trip unit, micrologic 3.2(LI) or 3.2S(LSI), is provided for both the 80% and 100% rated breakers. The units have a setting of 100A for the 100A frame regardless of whether it is a 80% or 100% rated breaker. If your statement is true, then a...
  7. RLebel

    80% rated breakers

    I am aware of the of code violation, however there is no way to prevent someone down the road from plugging in an additional 20A of loads in receptacles. And in this example, the breakers are rated for 80%, so the 100% does not come into the picture. This leads to my second question 2) A 100A...
  8. RLebel

    Sizing aluminum conductors to a 15kV Power Transformer

    The Canadian Electrical Code, section 26-258, requires that the conductors supplying transformers shall have an ampacity rating of not less than 125% of the rated primary current of the transformer. The NEC and CEC are usually pretty close to each other, so I wouldn't be surprised if something...
  9. RLebel

    80% rated breakers

    Most manufacturers advertise their breakers at 80% and in some cases 100%. I understand the NEC rules and its intent. My question is what happens to a 80% breaker which is loaded at 100%? Example: A distribution panel contains a mixture of lights and receptacles. The panel load is 80A. The...

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