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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...

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...

All, Just a general question that came to mind as I was reading today of a high rise residential tower that opened in Dubai, where each floor has a 1.5 degree twist from the floor below. this results in a total of 90 degrees of twist top to bottom. Quite a striking structure. It struck me...

Good afternoon, This may seem an odd question but it is something I have been asked to deal with. I am located in southern California. We are involved in the design of a hospital replacement building. This occurs in a seismic Zone 4 location, (for those unfamilair with that designation it is...

Hello all, Just a quick question, I've been googling for 1/2 an hour and can't dig up the information. I've been through both Caterpillar's and Cummins-Onan's site and none of their literature seems to publish the numbers. I know they used to, but I can't seem to find it. All I need is the...

Good Morning, I was hoping that some of you that perform substation design on a regular basis could point me in the right direction. We have a project that includes a customer owned, 15 MVA, 115kV/12.47kV substation. I am doing some preliminary design involving area planning and basic...

Good day all, I have an existing substation with a 500kV primary to 4.16kV secondary station transformer. We are extending the secondary overhead 3" aluminum busway to allow for us to connect a 10 mW solar power plant. I am mounting the VT's on the structures supporting the overhead busway. I...

Hello, Electrical engineers sometimes need to calculate the heating effects of running multiple electrical feeders in concrete encased duct banks. One of the most critical properties of the concrete used is the Thermal Resistivity, designated as "Rho" in most electrical code books. The units...

Hello, I am an electrical engineer. We often perform calculations on our multiple conduit duct banks to calculate the amount of heating that multiple runs of energized conductors impart to each other via their surrounding material. This tells us how much of the conductor's thermal capability...

Hello, I am in California and have a project which is to be reviewed by OSHPD. I am trying to call out the mounting of our electrical panels in an electrical room where the walls are fully grouted CMU. I was looking for a sleeve anchor, like the Hilti HLC-HX, but I can't find an OSHPD...

This morning while stuck on the freeway in Los Angeles, I looked up and noted an item I've seen for a long time and could never figure out it's purpose. Hopefully one of you transmission experts can explain this curious structure. Well structure isn't quite right, ...On some transmission...

Hello all, Does anyone out there know where I can find data on the Ampere rating for 3" aluminum IPS bus? I've googled till I'm blue in the face and all I find is connectors and accessories. Who is a supplier or manufacurer of this product? Hubbell has all the parts and pieces, connectors...

Hello all, I have an application where I need to get power out to a remote area of the site. Many years ago, I specified a piece of equipment that suited this situation perfectly. I no longer have the name of the manufacturer I specified and those documents are with a former employer and...

Hello, We have an installation with a total of four switchboards whose combined bus load rating is 13.75 MVA in one room. There are four switchboards made up of Metal Enclosed Low Voltage Switchgear. While giving the Mechanical fellows our anticipated heat loads for the transformers in the...

Do you think that URS is actually going to pay this? Or that their insurance carrier is in on the negotiations?

Good morning, Just trying to confirm what I believe to be the truth, but getting other 'eyes' on the problem never hurts. We have a couple of buildings under construction at a high school here in southern California. Contractor ripped up an on-site 4160V feeder with his backhoe. Well we are...

Hello all, This is both a code question as well as a technology question. Recently, I started doing some work for another of our offices where I noticed a fundamentally different approach to Fire Alarm System design. This is for public schools, K-12 in California. We are required to install...

This article discusses the current condition in NYC with triple digit temperatures hovering about for about 5 days. I wonder if one of you utility gents can answer a question that arises from a statement in the article where a substation manager requests "...a 4kV generator...". Is this the...

Gentlemen, (and ladies if applicable), Perhaps one of you can assist me in formulating an explanation for on of our clients that is clear enough for a layperson to grasp. In the process, helping me understand better the operation of a tool we use all the time. This is not my field of...