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Hello all, Just wondering if anyone had heard anything regarding the cause of the complete power failure at the Atlanta Airport, (Hartsfield-Jackson Atlanta International Airport). It is astounding to me that such a complete failure could occur. I have designed power and backup power systems...

Hello all, I noticed that the new Boeing 737-Max 8 and other models sport a new wingtip design. We've all seen the currently fashionable winglet design where the outboard 10% of the wing is swept upwards, I assume to take the drag vortices off the main plane, but this new design has a similar...

Dobber78, I don't think I have ever seen one paved for higher Voltages. I am not sure why you would want to. Paving implies rebar, wire mesh, etc..., for concrete strength and to limit cracking. I don't know how you would calculate the step potential for reinforced concrete at a switch or...

Hayeska, Correct me if I'm wrong, but the 12" horizontal leg of the verticals is overlapped and wire-tied or cadwelded to the horizontal bars. Those lengths would not be counted as additional developed length, it is the same conductor as the horizontal members to which they are attached. The...

hayeska, I think there are two problems with this detail. As has been noted by other posters, there appears to be 5" of concrete between the lowest horizontal layer of rebar and earth. This is the only steel that would even be in play. As waross pointed out, this would not comply with the...

arrehman1, Absolutely wonderful material, very well done. Thank you for sharing. EEJaime

cbark, We do this all the time. It is important to establish your Grounding system for the building at the building main service point. Since you will be bonding the neutral and ground busses in the main switchboard, this is where you want to originate your Grounding Electrode Conductor to your...

RSChinn, Well there's always the fact that anyone consciously breaking into a high Voltage substation to steal copper will get a grand dose of what is deserved. But it does pose a concern about infrastructure security. But as you've already stated, a chain link fence is not exactly a maximum...

hbendillo, I stopped using multi-wire branch circuits a few years ago. The common trip requirement defeats the purpose of using multiple circuits in an area to assure there is some power available where a single circuit has a problem. I, like yourself use multiple individual circuits in the...

Buddy91082, I think that is a code violation assuming you are in the NEC world and depending on your AHJ's interpretations. NEC 110-26(C)(1) requires at least one access to the space of sufficient size to allow access and egress from said space. "Egress" may be interpreted differently by some...

I don't know of actually manufacturing the product, but if you look up "ACA Solutions" they have a lot of information and performance data on bus piping and tubing. As well as connectors and electrical characteristics. They are a division of AFL Telecommunications. If you Google ACA Conductor...

ajk1, I don't know of any specific code requirements. I do know that our electrical utility companies have published standard designs for their minimum requirements to protect their above ground structures and equipment. This is in the US, so I don't know that it would necessarily apply to...

catserveng, Thank you for the lead and link. That is the type of information I am looking for. We are working in the San Diego area as well, so I will follow up on that. I appreciate the information. Have a good day, EEJaime

Hello all, Just an inquiry regarding the use of fuel cells in an interactive system as defined in the NEC. Has anyone had experience in the use of multiple unit parallel installation of fuel cells to provide on-site power production to reduce the utility demand? What are the advantages and...

simisteven, I have had success with CSD's product's, they also work in conjunction with other popular fire stop product manufacturers. Try: http://www.arcat.com/divs/sec/sec07840.shtml . They are represented in the UK by Thorne & Derrick UK. In the States by CSD Sealing Systems North America...

All, My OP was not at all disparaging of any profession. I was admiring the innovation and the SE's abilities to make such a different and seemingly unlikely structure a success. It has been my privalege to work on a few projects which pushed the envelope of applied engineering in many fields...

This thread has gone way over the top. LOVE IT. I couldn't figure out what that question meant with a roadmap! Wow. Good day, EEJaime

I just can't see this as a stable structure! It seems so "what were you thinking"? Kind of special. EEJaime

That is amazing to me because the mass at high elevations would seem to be detrimental to the footing design. Especially with a design that makes even wind load calculations a challenge. Do you integrate the wind for theb90 degree rotation? That needs a wind tunnel test! EEJaime

Hokie66, Thank you. Very informative article. I would not have guessed concrete construction. I would have guessed steel, some kind of braced frame. I guess that is why we leave that sort of thing to you structural experts. Just seems counter-intuitive. Good day, EEJaime