Motor Branch Circuit Short Circuit And Ground Fault Protection (13min:31sec)
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- čas přidán 23. 02. 2011
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Mike Holt Enterprises offers comprehensive electrical training materials delivered in a logical, easy to understand format that helps build a solid understanding of electrical concepts, calculations, and code material.
This video was extracted from Mike Holt's Illustrated Guide to Understanding the National Electrical Code Volume 1, based on the 2011 NEC. Branch-Circuit Short-Circuit and Ground-Fault Protection - Article 430.52
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you guys are helping me wrap my head around this! Thanks i love the videos!
This info is awesome, thank you very much in providing these videos.
You are most welcome, God Bless, Mike Holt.
I see the light now. excellent video
The reason this is ok is, the start of that motor is brief and not a consecutive load.
Thank you! What about an AC Servo Motors. Do they obey the same rules as regular AC motors? If the manufacturer of the VFD or servo motor Drives recommends nominal of MCB. do I need to consider these recommendations?
I have question where I can find exactly say 12 ft is between two receptacle in dwelling unit
Any point has to be 6 feet from an outlet, so 12 feet between 2 outlets max:
NEC 2017 210.52 Dwelling Unit Receptacle Outlets.
A ) General Provisions. In every kitchen, family room, dining
room, living room, parlor, library, den, sunroom, bedroom,
recreation room, or similar room or area of dwelling units,
receptacle outlets shall be installed in accordance with the
general provisions specifed in 210.52(A)(1) through (A)(4).
1) Spacing. Receptacles shall be installed such that no point
measured horizontally along the floor line of any wall space is
more than 1.8 m (6 ft) from a receptacle outlet.
motors and generators will work with greater efficiency on a body with limited gravity. A motor trys to speed match its generator. Gravity, air drag and resistance creates a current buildup.
Hi mike just a little bit confuse about the Voltage and FLC. Your motor is 3 phase 7 1/2 HP why you use 230V and 22A FLC. Is there a 3phase motor operated in 230V. Or maybe you should use 460V, 11A FLC in 3 phase motor 7 1/2 HP in your sample. Please answer this.
Motor 'nameplate voltages' are 115, 230, 460, and system 'Nominal' voltages are 120, 240, 480 [220.5(A)]. When the NEC specifies you to use the motor nameplate current or voltage, then you use the nameplate values; when it doesn't say 'nameplate' then you use the nominal voltage (120, 240, 480) or the FLC on the tables in Article 430.
Thanks Mike!
How did you know it needed an ITB?
It's part of the example. If you want, you could use fuses and use the percentages on Table 430.52.
in this case the breaker should be 20 A
simply a std breaker will be tripping to 6-8 time his rating , to permit starting the code said no more than 13 time the full load current , so 20 A is enough , i know the American code will permit 250 % , i had worked 26 years as a motor control specialist at klockner Moeller
mike is a horrible story teller
Lol... never been told that before. Have a great day.