Concrete foundation electrodes

Using Foundation re-bar below ground level can provide low resistance system in solving difficult earthing problem. Some called it Ufer electrodes in honor to Mr. Hubert Ufer who conducted thorough researched and testing of concrete foundation electrodes.

Methods using CADWELD or Thermo welding and Mechanical splicing to the re-bars are accepted. However using steel wire in splicing is highly prohibited since it can loosened the splicing of copper wire to the re-bar when the concrete pouring will commence.
Further reading.

http://www.psihq.com/iread/ufergrnd.htm
http://www.psihq.com/iread/ufergrnd.htm

Differentiating between frigates, destroyers and cruisers

Im trying to find out the good answer to this question about the sizes of combat ships , here are some valid points that i collected from other open sources.



To the uninitiated, telling the difference between frigates, destroyers and cruisers is difficult. However, there are three major differences: the command, the shape, and the size.(from AC Generals who befriend me)

Command:
The Navy has required by law that the commanding officer of a cruiser has attained the rank of Captain. The commanding officer of a destroyer or frigate must have achieved the rank of Commander, one paygrade below Captain. In my personal experience, the officers (in general) of frigates tend to be the youngest, while the officers of cruisers tend to be the oldest.

Shape:
All cruisers have two masts. All frigates have one mast. This is a historical difference, as cruisers in the Eighteenth Century and early Nineteenth Century had more sail area in their sail plan, and therefore tended to sail faster. Destroyers have either one or two masts. If it has one mast, like the DDG-51 class, it is a slanted mast, unlike the vertical mast of the frigate. If it has two masts, like the DD-963 class, the forward mast is taller than the aft mast. On a cruiser, the aft mast is the taller of the two.

Size:
In comparison of pure size, cruisers tend to have a high masthead height, with large superstructures. Their beam (width) is extremely narrow compared to a destroyer, which has a beam usually 10 feet or more wider. Destroyers also tend to have a smaller freeboard. The squat dimensions of a destroyer allow it to be extremely maneuverable as a weapons platform, while the tall, narrow, long dimensions of a cruiser give it speed, even in rough seas.


In many navies, including the USN to a point, the distinction between weight classes is very nearly arbitrary. In general, the smallest class of 'proper' surface combatant is the corvette. Next in line is the frigate, followed by the destroyer and then the cruiser. Above this lie battlecruisers and battleships. There are no battleships left in service, and no battlecruisers either except for the debatable example of the Kirov class, which most would call merely an unusually large cruiser. There are, however, some general guidelines.

Corvettes are quite small, between 500 and 2000 tons displacement. The distinction between a large missile boat and a proper corvette is very nebulous, however. Frigates are a bit easier to identify. They are almost without exception 2500 tons displacement or more, and usually armed for one main mission. In most cases, this one mission is anti-submarine warfare, though there are anti-aircraft frigates as well. Frigates tend to be long and very narrow, and often have a sharply raked bow, which places the anchors in a position where they won't strike the sonar dome. Most also have low, squat superstructures and a single mast, though two-masted frigates do exist. The US Navy's Oliver Hazard Perry class and the British Type 23 frigate are very good examples of the type. The Spanish Alvaro de Bazan, on the other hand, is not, being rated as a frigate but having the size and armament of a destroyer.



Perry Class Frigates , USS Oliver Hazard, US Navy





Jacinto Class Corvette , BRP Artemio Ricarte PS37, Philippine Navy


The exact cutoff between a very large frigate and a small destroyer is rather hazy, though in general, destroyers can undertake two missions, perhaps more, with equal ease. For example, the now-retired Spruance class destroyer was equipped for both anti-sub and anti-surface warfare, with anti-air self-defense capability. Other examples, like the British Type 42 or the Russian Sovremenny class are similarly multi-mission. Most destroyers are a bit broader in the beam than frigates and tend to have higher superstructures. Both single- and dual-masted configurations exist. Most destroyers are between 4500 and 7000 tons displacement, though more recent examples can be larger, often approaching 9500 tons as in the case of the Arleigh Burke class. Some newer classes, like the aforementioned Burkes, or the Japanese Kongo class, are fully multi-mission and verge on being cruisers.



The cruiser is an even hazier category, mostly because few examples exist. In general, cruisers displace upward of 10000 tons and are more heavily armed than a destroyer. Most are also fully multi-mission, able to undertake anti-air, anti-sub or anti-surface strikes, and most also have some land attack capability. There are four classes of cruiser still in service - the American Ticonderoga, the Russian Kirov and Slava and the Peruvian Almirante Grau. The Peruvian unit is a converted World War II-era Dutch light cruiser, and has no anti-aircraft missile systems, or any anti-sub armaments at all. She is something of an anachronism, and not typical of modern cruiser design. Of the remaining 3, the US type is a long, narrow-hulled dual-masted vessel with a large boxy superstructure. The Russian varieties are long, but broader with very sharply raked bows. Both Ticonderoga and Slava have two masts; Kirov, on the other hand, has only a single very large mack (mast and stack combination). All three are fully multi-mission, though the anti-ship missiles occupy much more prominent positions on the Russian designs. This is in large part because the SM-2 Standard that comprises the main armament of the Ticonderoga class was designed from the inception as a dual-purpose missile and that's only become more true with subsequent revisions. The Russian units employ separate launchers for every missile type and thus have a busier, more heavily-armed appearance, while the American type has a dedicated launcher only for the RGM-84 Harpoon missile, using its Mk. 41 VLS for everything else.



Arleigh Burke Destroyer, USS Arleigh Burke, US Navy




Ticondera Class Cruiser, USS Port Royal, US Navy




Gun armament used to be a deciding factor, but no longer is - the largest guns in use on any surface warship still in commission are Almirante Grau's eight Bofors 152mm/45 naval rifles. Besides these, the Russian AK-130 130mm/70 is the largest modern gun in use. Smaller weapons, typically 127mm, 114mm, 100mm and 76mm are used by most other navies, and are used on frigates and destroyers as readily as on cruisers. Most corvettes, and some frigates carry 57mm weapons instead. The Canadian Halifax class frigate (more of a light destroyer) is an example of this. Italy is the only nation which still routinely equips their ships with extensive gun armaments nowadays, though Russia's Sovremenny class destroyer, carrying four 130mm guns, is something of an exception. The forthcoming, but not yet constructed DDG-1000 class, also known as DDX, will feature two 155mm/70 heavy guns and two or four 57mm heavy autocannon as point defense, however.


Iowa Class Battleship , USS Iowa, US Navy






Iowa Class ,USS Missouri firing Tomahawk missile during Gulf War




Yamato Class Battleship of the empire of Japan ,Biggest Warship ever with 18 inch Main Gun





Yamato under fire from US warplane during WW II

BIL

" BIL" means? in Electrical engineering?

BIL is Basic Impulse Level or sometimes some other referred to as "Basic Insulation Level".

It represents the "strength" of equipment's (transformers,motors)insulation for a high-voltage impulse. The impulse wave form is often 8 by 20 milliseconds -- An 8 ms rise and 20 ms in duration.

Here is a quote from C57.12.00:

"Transformers shall be designed to provide coordinated low-frequency and impulse insulation levels on line terminals and low-frequency insulation levels on neutral terminals. The primary identity of a set of coordinated levels shall be its basic lightning impulse insulation level (BIL)."

Each voltage class of equipment has a ANSI standard BIL rating. For example: 15 kV is the most common distribution voltage class in the US. Equipment installed on a 3-phase, 4-wire circuit in the 15 kV class with have a BIL rating of 95 kV. (The 15 kV class includes voltages from 11.8 kV through 14.4 kV. The most common actual system voltages are 12.47, 13.2, and 13.8 kV.)

The appropriate rating depends on whether the equipment is effectively grounded and/or connected to a 3-wire or 4-wire system. Some of the more common BIL ratings used on distribution equipment in North America are 60, 95, 125, 150, and 200 kV.

Transmission and substation equipment has a minimum BIL rating of 110 kV. Here are some of the minimum BIL ratings for various transmission voltages:

System - BIL
138 kV = 450 kV
230 kV = 650 kV
345 kV = 900 kV
500 kV = 1130 kV
765 kV = 1800 kV



Source(s):
C57.12.00 - IEEE Standard General Requirements for Liquid-Immersed Distribution, Power, and Regulating Transformers

Faulty Electrical Wiring

There is no such thing as faulty electrical wiring according to some electrical engineers due to the fact that it cannot be operational in the first place.

However, I disagree we have to be specific and know the fact when we used the term “Faulty electrical wiring” .

Here are some instances.

Do you think you may have a problem with your electric wiring? Did you know that there are more than 40,000 fires caused by bad wiring or improper use of electric cords and appliances.

If you’re concerned about your home wiring, here are some tips about what causes electric fires, what the signs may be and a recommendation from the Consumer Products Safety Commission about how to help protect yourself.

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We know: Signs of Faulty Electric Wiring

Be Aware and Know the Facts

Is an older house more at risk for wiring problems?

Half of the nation’s housing stock is more than 30 years old. Many older homes were not designed to meet current-day electricity demands. An older home doesn’t necessarily mean a hazardous home, but if you live in one, you should be aware that wiring could be a problem.

What are the problems with older homes?

Homes that are 100 years or more old, were wired at 30 amps. By mid-century, that had increased to 60 amps. More recently, homes have been wired at 150 to 200 amps. Some new homes are wired at 800 amps.

If your home was wired before the 1950s, it may have poor wire insulation, ungrounded (2 prong) outlets, and fuse boxes instead of circuit breakers. All of these things increase the risk of fire and accident.

http://www.ineed2know.org/ElectricWiringTips.htm