If I have a hypothetical 480/277V, 3 Phase, 4 wire feed to a distribution panel. (Spare panel for future use, we do not know the load) Do you de-rate because it is 4 wire? Following 310.15(B)(5)(c) If the majority is non-linear (meaning greater than 50%?) we would de-rate because of 4 wire. (Correct?) Or does this apply only to a branch circuit,… Show more
All Retail Shops are recommended to be provided with Quick Response Sprinklers. Fire Size used in the calculations is 2.5 MW considering Quick Response Sprinklers in compliance with BS 7346 Part 4 Table 3. NFPA – 13, 22.214.171.124.3.1 where listed quick-response sprinklers, including extended coverage quick-response sprinklers, are used… Show more
Hello, I am looking for data concerning the electric loads in the USA. Is there any official document stating how max is the electric load in the private and public sector? Are there any statistics or studies related to it? I found a document on the website, but the document has problems in being downloaded. Can anyone help me in this? Thank… Show more
Does this building require a suppression system? Conditions: Existing motel built in the late 1960s Abandoned (4-6 years) Under remodel (new drywall, plumbing, electrical, mechanical) 60 units 12,000 sq foot building Fire resistive (cement block) construction Two stories Rooms exit to the parking lot… Show more
We are having a debate about the correction factor for ambient temperature and the adjustment factor for conduit fill over 3 current carrying conductor. The question is do you need to apply both if you have an ambient temperature greater than 86 degree and more than 3 current carrying conductors? Or do you use which ever is greater, adjustment… Show more
Does anyone have any experience with 3D printers as they pertain to use of a space and any particular fire code requirements? I perform inspections at a large university and I'm seeing several in lab spaces; they always seem to be running flat out, and I wonder about their power demand on the building. Thanks in advance! code inspection
I have had zero luck with this but several differing opinions We were trying to judge the ampacity of an existing cable, 3 conductors 500KCM in one jacket or cable. This cable is attached to building rafters, about 10 ft between rafters and the cable is surrounded by air above below beside and is indoors near roof no other conductors … … Show more
When working inside confined spaces must electrical lighting circuits be seperate form circuits supplying power tools, ventilation equipment, etc.?
When working inside confined spaces must electrical lighting circuits be seperate form all other electrical circuits? Where in the NEC is this subject addressed?
Why is #6 Copper NMB cable's ampacity restricted to the 60deg Celsius rating even though it's actual manufactured ratings are to 90deg Celsius? It's ratings match type SE cable's specs, and it manufactured and rated to 90deg Celsius. I could pull the THHN conductors out of the NMB cable, pull them into conduit and now, they are rated to 90deg… Show more
Just few days ago had a training about https://catalog.nfpa.org/NFPA-72-National-Fire-Alarm-and-Signaling-Code-2019-3-day-Classroom-Training-with-Certificate-of-Educational-Achievement-P458.aspx NFPA 72 (2019) Classroom Training in Bangladesh, i participate there and gave the exam. There was a result and i dropped it but i was so confident that i… Show more
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I have a feeder circuit - power coming into a terminal block rated for 175A then wired to a 50A contactor to a compressor with an RLA of 28.8A. The terminal block states 75C wire and the compressor states use minimum 75C wire for ampacity determination. We are contemplating either 8AWG or 10 AWG MTW - THHW wire for this circuit. The circuit… Show more