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Hello everyone, Thanks for your comments I reviewed many vendors available in the market and, as you indicated, 300ms in the standard value I used to think that more than 500ms was required to coordinate the incomer with the outgoing circuit-breakers but I think that is only required in MV...

dpc, thanks. I like your comment on the following: The problem is how to calculate arc current before buying que equipment and performing protective devices coordination study 😅 JBC ....... "The more I read, the more I acquire, the more certain I am that I know nothing"

Hi jraef, thanks for posting. So based on IEEE point of view, I shouldn't set the incomer overcurrent protection to more than 500ms, right? That seems quite low if you need it to coordinate with 3 or more downstream protective devices I know short circuit withstand ratings and arc flash...

Hello guys, I would like your opinion regarding the following issue: Since the short-circuit level in an installation I am designing is about 60kA, I am asking for IEC LV switchgears rated 65kA/1s and also being arc resistant (65kA/1s arc duration) One of the bidders is offering 65kA/1s...

Hi jraef, Thanks for your replay. I think the same as you but I wanted to have another point of view MV motors to be installed range from 800 to 2500 kW Regards, JBC ....... "The more I read, the more I acquire, the more certain I am that I know nothing"

Hello, quick question: Is a 4000V IP24W IC01 motor suitable to be located outdoors in a really rainy power plant? What about IP24W IC 411? Does this combination even exist? Many thanks, JBC

Hello, I am working on a project for a Power Plant that requires a DC+UPS system like the one in the picture below The two redundant battery chargers as well as the two inverters are a 'customer requirement', but it remains 'open to interpretation' if two STS (Static-Transfer-Switches) + two...

Hi marvinc24, If you run a short-circuit calculation (at least under IEC), Pos-Neg & Zero sequence impedances are shown in the 'output report' for each bus faulted Regards, JBC ....... "The more I read, the more I acquire, the more certain I am that I know nothing"

Hello, I need to specify a 4.16 kV Switchgear for a Thermal Generation Plant. I have some 'examples' but I would like another one. I need to write an engineering deliverable. Does anyone have a Technical Specification (word/pdf) to share? I want to cover every important 'topic' Thank you in...

Thank you all for your reply I am reading that cable trays and metallic conduits (as RMC or IMT) can be used as EGC as long as they meet some requirements. In that case, an "extra" EGC within the power cable is not necessary, am I right? Is this still valid if the entry to the boards/motors...

Hi, Imagine a big (O&G/power plant) facility (composed of many buildings and equipment) that has a large grounding mesh beneath it. This mesh is completely interconnected with each other. Is it mandatory that every power cable feeding different boards/motors in this installation has a...

Hello, Motor rated power and torque (output) is directly proportional to the square of the voltage. If you use a 460Vac motor on a 400Vac network, it won't be able to develop the "rated torque", and instead, will develop (400/460)^2 = 75.6% of it. What will happen depends on the mechanical...

Hi PoliPoli, Find attached the ones I've got. I asked them to ETAP HelpDesk as I need them. You can do the same here https://helpdesk.etap.com/cgi-bin/wonderdesk.cgi (you need an original serial no.) Regards, Juan JBC ....... "The more I read, the more I acquire, the more certain I am that I...

Hi, Option C for those who are poor: Watch youtube videos and look for free online courses. There are lot of them JBC ....... "The more I read, the more I acquire, the more certain I am that I know nothing"

Also take a look at this: https://www.eng-tips.com/viewthread.cfm?qid=440427 JBC ....... "The more I read, the more I acquire, the more certain I am that I know nothing"

Hi. Take a look at the picture attached. It is from IEC 60076-5. GL JBC ....... "The more I read, the more I acquire, the more certain I am that I know nothing"https://files.engineering.com/getfile.aspx?folder=a39cb229-e1b9-4d82-99f1-0b8ff13e97e3&file=IEC60076-5.png

Thank you! I hope you find it useful. If you have any questions, let me know JBC ....... "The more I read, the more I acquire, the more certain I am that I know nothing"

Hi 7anoter4, Try with this file (.xltm). Tables are in hidden sheets. The macros are only used to open different menus but they do not take part in the calculation, all the calculation is perform "comparing" tables. Regads, JBC ....... "The more I read, the more I acquire, the more certain I...

Hello guys, I would like to share with you a worksheet that I've developed, aimed to size LV power cables (Up to 1kV) using IEC 60364-5-52 (https://webstore.iec.ch/publication/1878) Some information may be weird to many of you, since I live in Argentina and here we do not follow just one...

Hi Bill, What is the origin of that designation? Are manufacturers trade-names or are they specified in a standard? Here in Argentina, we don't use that names. I just want a generic notation for multi-cores cables included a PE conductor Thanks, JBC ....... "The more I read, the more I...