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  1. If I want to list the largest motor FLA for a...

    If I want to list the largest motor FLA for a machine that has a refrigeration compressor as its largest motor, would I use the MOC of the motor?

    Refrigeration compressors use RLA (Rated Load...
  2. Petersonra, do you call it a suggestion since it...

    Petersonra, do you call it a suggestion since it is an NFPA79 requirement and not an NFPA70 requirement? If one were to follow 409.110 alone, I would not have to add the largest HP motor or load...
  3. Is this asking for the largest branch OCPD...

    Is this asking for the largest branch OCPD located within the equipment? Would this be so that the installation of the equipment overcurrent protection can be in compliance with NEC 409.21(C), or is...
  4. NFPA 79 (2015) Machine Nameplate Data Question

    I have a question about 16.4.1(5), where it is required to display the "Maximum ampere rating of the short-circuit and ground fault protective device, where provided".

    I am having trouble with the...
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    Whatever advantages they have by using the single...

    Whatever advantages they have by using the single phase 230V to neutral approach vs our 120V/240V split-single phase approach is completely wiped out by their use of 50 Hz. Whereas 60Hz was...
  6. Thread: Kapton Tape

    by fifty60
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    Kapton Tape

    I have a tytpe T thermocouple that is used to connect to the device under test (DUT) inside of an environmental test chamber. The temperature inside of the chamber can be between -70 to 190 C. The...
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    Sizing Delta vs Wye 3 Phase Calculator

    Is there any difference in sizing a Wye primary transformer over a Delta primary transformer? For example, I have a 25KVA three phase transformer at 380V. I get 25000/(380*1.73) = 38A. Is this the...
  8. Thanks for clarifying that for me.

    Thanks for clarifying that for me.
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    I had a technical-writer friend of mine recently...

    I had a technical-writer friend of mine recently tell me "You are trying to convey technical information, not write a romance novel." For some reason this really resonated with me. Get to the...
  10. Table 450.3(B) OCPD for Transformers (1000V or less)

    The way I read this table is that for a transformers that has a primary current of 9A or less, if I size the primary OCPD at 167% rounded down, then I do not need any secondary protection. But, if...
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    Thanks for the explanations. For 208V 3phase...

    Thanks for the explanations. For 208V 3phase systems, there should not be any situation where the voltage to ground exceeds 277V. Is that correct? So any system below 277VAC, whether single phase...
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    Thank you sir. So if I am using the breakers on...

    Thank you sir. So if I am using the breakers on a 240 volt single phase supply, even though it is single phase, I should list the supply voltage as 240VAC Y ?

    Also, this only applies to the...
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    My breaker is 480/277 rated. After going over...

    My breaker is 480/277 rated. After going over this post, and others, It is my understanding that these are safe to use on a 480Y system. They are also safe to use on a 480 Delta system, as long as...
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    NFPA 79 Code Cycle?

    Anyone know what NFPA 79 code cycle is active for Ohio?
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    Yes, I agree that is the case Packersparky. My...

    Yes, I agree that is the case Packersparky. My reference to UL field tests was meant to convey that the same equipment has been inspected by UL before, and the above was never mentioned. I believe...
  16. I read 82 cold (at ambient 24 C) ohms and then 85...

    I read 82 cold (at ambient 24 C) ohms and then 85 ohms after the motor was finished operating. The motor only operates for around 13 minutes, then shuts off for several hours if not days. It is a...
  17. Thanks Bugman1400. The motor is a NEMA 56...

    Thanks Bugman1400. The motor is a NEMA 56 TEFC...is this different than an open end bell?
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    The inspector is referencing OSHA Regulations ...

    The inspector is referencing OSHA Regulations 1910.304, in particular:

    1910.304(g)(4)(i)
    For a grounded system, a grounding electrode conductor shall be used to connect both the equipment...
  19. Winding Temperature with Infrared Thermometer

    Can you use an infrared thermometer to determine the winding temperatures of a three phase motor?
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    The equipment is not UL listed, but has been UL...

    The equipment is not UL listed, but has been UL field tested in the past. What is NEC 250.4(A)(2) trying to say? Is this requiring a grounding strap for ESD?
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    He may be talking about what is pointed out in...

    He may be talking about what is pointed out in 250.4(A)(2). This appears to not be the Equipment Grounding Conductor, but the connection to earth for lightning and other surge type protection. I do...
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    Chassis Ground Where Service Enters Machine

    I have equipment (roughly the size of a small refrigerator turned on its side, it is not a refrigerator however) that is cord and plug connected to a 20A 120V outlet. The cord enters the rear of the...
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    Understood. A different example. If the Max...

    Understood. A different example. If the Max Fuse Size is 30A, and the minimum circuit ampacity is 19A, would I be able to use a 30A fuse and #12AWG wire?

    Does the MCA coincide with the max fuse...
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    MINIMUM CIRCUIT AMPACITY

    When a refrigeration compressor states the max fuse size and a minimum circuit ampacity, does this mean that for the maximum fuse size you can use the stated minimum circuit ampacity?

    For...
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    T/C's in Humid Environment

    I have an application where I will weld the end of a T/C grade wire to use as a sensing point inside of a humid atmosphere (up to 95% humidity at 85 C).

    Normally, I would use a stainless steel...
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