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2011 National Electrical Code Changes

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Czech Grid Operator Says German Power Flow Overloaded Network - Bloomberg

The Czech power grid in 2011 was repeatedly and “more frequently” overloaded with unscheduled flows of electricity caused by renewable energy from Germany, jeopardizing the security of the network, grid operator CEPS said. The most critical situation occurred in the period between Nov. 25 and Dec. 16 when unscheduled power flows amounted to 3,500 megawatts while the usual value is about 1,000 megawatts, the Czech operator said in a statement today on its website. The near-emergency situation in the network was mainly caused by excessive power output from German wind farms on windy days. The shutdown of German nuclear plants, the rise of installed capacity in photovoltaic power plants in Germany and intensive power trading on spot markets also played a part in the network overloads, CEPS (PCZPBL01) said. CEPS has implemented measures to identify and predict such situations and said the risk of the recurrence of such situations in the future still persists and the transmission networks in the region must be reinforced as quickly as possible, it said. The country may have to install transformers at the borders to protect the grid at a cost of 2 billion koruna ($99 million), CEPS chief Vladimir Tosovsky told reporters at a press conference in Prague today, newswire CTK reported. CEPS already plans to invest 3.5 billion koruna in the network in 2012, the newswire reported.

Grounding and Bonding - Questions and Answers 1

http://www.webcitation.org/6D1mxnVzg // Neutral and Ground Connections At service equipment the NEC permits the grounded (neutral) conductor, the equipment enclosure, and the grounding electrode conductor to all terminate together. Is it permissible to land the equipment grounding conductors on the neutral bus bar with the grounded (neutral) conductors, or am I required to set a ground bar for the equipment grounding conductors? A1: Equipment grounding conductors can terminate on the same terminal bar with the grounded (neutral) conductors, but this is only permitted if the panelboard is rated service equipment and it is used as service equipment in accordance with 230.71(A). However, each grounded (neutral) conductor must terminate within the panelboard in an individual terminal [408.21]. // Grounding Remote Building and Structures NEC 250.32 allows the grounded (neutral) circuit conductor supplying a second building to be bonded to the equipment grounding conductor at the remote building. grounding electrode system of the second building. If the two buildings are electrically connected via a conductive path, such as the shielding of a coax cable or water pipe, this would provide an alternate path for neutral current to flow during normal operation (like resistors in parallel). Is this a trivial concern? Do you know of any problems that can arise from such a situation such as GFI relays in the main service? All those whom I have discussed this with have dismissed it as trivial. They site residential houses connected via a common water line.

Radio World: A/C Color Code Is for Your Own Good

Although the National Electrical Code doesn’t require a specific color code for ungrounded conductors, electricians often use the following color system for power and lighting conductor identification: • 120/240V, single-phase wiring — black, red and white • 120/208V, three-phase wiring — black, red, blue and white • 120/240V, three-phase wiring — black, orange, blue and white • 277/480V, three-phase wiring — brown, orange, yellow and gray; or, brown, purple, yellow and gray On the grounded side for neutrals, the wires have to be white or gray. Buc prefers white at 120/240 (208) and gray for 277/480 circuits. Green or bare wire is always the grounding conductor. Personally, Buc specifies the latter 277/480 color grouping; that removes the “orange” wire color and any confusion. Why? Orange is the only specified ungrounded conductor and marks the “wild leg” of a 120/240 center-tapped neutral delta configuration. For those unfamiliar: In wild leg configuration, the two end phases on the center-tapped winding provide 120 volts to neutral, but on the wild leg you will find nearly 208 volts to the neutral. If you see an orange wire in a panel, alarm bells of caution should go off in your head. You don’t want to wire a 120 VAC outlet across the wild 208 volt phase.

Electrical Contractor: Significant Changes for the NEC 2008 -Part 4

http://www.webcitation.org/6Cz1rWR1V // (removed by 2008 NEC to prevent inappropriate ground connections from happening later on) // 2005 NEC—250.32 Buildings or Structures Supplied by Feeder(s) or Branch Circuit(s). (B) Grounded Systems. For a grounded system at the separate building or structure, the connection to the grounding electrode and grounding or bonding of equipment, structures, or frames required to be grounded or bonded shall comply with either 250.32(B)(1) or (B)(2). (1) Equipment Grounding Conductor. An equipment grounding conductor as described in 250.118 shall be run with the supply conductors and connected to the building or structure disconnecting means and to the grounding electrode(s). The equipment grounding conductor shall be used for grounding or bonding of equipment, structures, or frames required to be grounded or bonded. The equipment grounding conductor shall be sized in accordance with 250.122. Any installed grounded conductor shall not be connected to the equipment grounding conductor or to the grounding electrode(s). (2) Grounded Conductor. Where (1) an equipment grounding conductor is not run with the supply to the building or structure, (2) there are no continuous metallic paths bonded to the grounding system in each building or structure involved, and (3) ground-fault protection of equipment has not been installed on the supply side of the feeder(s), the grounded conductor run with the supply to the building or structure shall be connected to the building or structure disconnecting means and to the grounding electrode(s) and shall be used for grounding and bonding of equipment, structures, or frames required to be gro

2011 National Electrical Code Changes | NEC content from Electrical Construction and Maintenance (EC and M) Magazine

The ampacity of some conductors in Table 310.15(B)(16) (formerly 310.16) didn’t match those found in the Canadian Electrical Code and were therefore changed. While no technical evidence was submitted showing insulation failure of the conductors, this proposal was passed. The end result was a change to the ampacities of: Copper conductors: 14, 12, 3, and 1 AWG, and 600kcmil, 1,500kcmil and 2,000kcmil. Aluminum conductors: 12, 8, and 6 AWG, and 300kcmil, 700kcmil, and 800kcmil.