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  2. Earthing system - Wikipedia

    en.wikipedia.org/wiki/Earthing_system

    An earthing system (UK and IEC) ... There are several types derived from copper and steel: copper-bonded, stainless-steel, solid copper, galvanized steel ground. In ...

  3. Standard atomic weight - Wikipedia

    en.wikipedia.org/wiki/Standard_atomic_weight

    The standard atomic weight of a chemical element (symbol A r °(E) for element "E") is the weighted arithmetic mean of the relative isotopic masses of all isotopes of that element weighted by each isotope's abundance on Earth. For example, isotope 63 Cu (A r = 62.929) constitutes 69% of the copper on Earth, the rest being 65 Cu (A r = 64.927), so

  4. Copper - Wikipedia

    en.wikipedia.org/wiki/Copper

    Copper has been in use for at least 10,000 years, but more than 95% of all copper ever mined and smelted has been extracted since 1900. [35] As with many natural resources, the total amount of copper on Earth is vast, with around 10 14 tons in the top kilometer of Earth's crust, which is about 5 million years' worth at the current rate of ...

  5. Bimetallic strip - Wikipedia

    en.wikipedia.org/wiki/Bimetallic_strip

    Copper, steel, brass, iron, and nickel are commonly used metals in bimetallic strips. [6] Metal alloys have been used in bimetallic strips as well, such as invar and constantan . Material selection has a significant impact on the working temperature range of a bimetallic strip, with some having a temperature limit up to 500°C, with others only ...

  6. Isotopes of copper - Wikipedia

    en.wikipedia.org/wiki/Isotopes_of_copper

    Most of the others have half-lives under a minute. Unstable copper isotopes with atomic masses below 63 tend to undergo β + decay, while isotopes with atomic masses above 65 tend to undergo β − decay. 64 Cu decays by both β + and β −. [1] There are at least 10 metastable isomers of copper, including two each for 70 Cu and 75 Cu.

  7. Busbar - Wikipedia

    en.wikipedia.org/wiki/Busbar

    Copper busbar in a panel 1500 ampere copper busbars within a power distribution rack for a large building In electric power distribution , a busbar (also bus bar ) is a metallic strip or bar, typically housed inside switchgear , panel boards , and busway enclosures for local high current power distribution.

  8. AOL Mail

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    Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!

  9. Ground and neutral - Wikipedia

    en.wikipedia.org/wiki/Ground_and_neutral

    The neutral conductor of a 3-phase, 4-wire system and the middle conductor of a 2- phase, 3-wire system must have at least 2 separate and distinct earth connections with a minimum of 2 different earth electrodes to have a satisfactory earth resistance; The earth electrodes must be interconnected to reduce earth resistance