Indoor Wiring Research Articles

Experimental Study on the Fire Smoke Characteristics of an Insulated Wire Jacket for Indoor Wiring Using a Smoke Density Chamber

A wire jacket that prevents leakage of electric current flowing through wires is made of polymer composites. The flame spreads widely with a large amount of smoke passing through the wire jacket when a fire occurs. As smoke hinders safe evacuation, it is important to determine the smoke characteristics of the wire jacket for safe evacuation. Therefore, in this study, the specific optical density was measured for 1800 s in the presence and absence of ignition flame under a radiant heat flux of 25 kW/m2 according to the ISO 5659-2 combustion chamber method. From the experimental results, the extinction coefficient and visibility indicating the degree of transmission of light and VOF4 indicating the smoke density characteristics at the beginning of combustion were derived. The experiment was conducted with a wire jacket comprising PVC and a wire jacket comprising XLPE of low-toxicity flame-retardant cross-linked polyolefin. The maximum specific optical density was higher for PVC than for XLPE with and without the ignition flame. Except for the case of XLPE with an ignition flame, the extinction coefficient of the wire jacket was > 3.5 m-1, with a visibility of 0.2-2 m. PVC exhibited a higher maximum specific optical density in the absence of the ignition flame than in the presence of the ignition flame; however, VOF4 was higher in the presence of the ignition flame.

Early Recovery and Section Reduction Measures in the Event of a Power Outage Caused by Electric Leakage or Overcurrent in Indoor Wiring

Early Recovery and Section Reduction Measures in the Event of a Power Outage Caused by Electric Leakage or Overcurrent in Indoor Wiring

Parametric change in Insulation Resistance and Breakdown Voltage of Underground PVC Cables under Accelerated Multistress Aging Conditions

PVC is widely used as an electrical insulation for low-voltage indoor wiring and underground cabling. These cables are attacked by contaminants and chemicals present in the soil. The elevated temperatures and pressures inside the soil also adds up to stresses and deteriorates their insulations and sheaths and this eventually goes on damaging the conductors. So their performance in the contaminated service environment should be investigated considering extreme conditions in order to predict and ensure reliable service life. In this research 4 different PVC cable samples (2 core 10 mm2, 4 core 10 mm2, 4 core 120 mm2 and 4 core 240 mm2) were subjected to mechanical (via small punches), thermal, chemical and electrical stress over each core of the cable. Electrical stress was applied with 1 kV AC transformer. These samples were aged for 1000 hours under International Electrotechnical Commission (IEC) 1000 hours multistress aging conditions. Visual inspection and electrical characterization was done by Breakdown Voltage and Insulation Resistance Test for insulation and sheath at different intervals to investigate early stage degradation and reduction in lifetime. The results were compared with the characterizations already reported in the literature. Physical appearance and chemical degradations were apparent from the visual inspection of end aged samples. Quantitatively the results also indicated the continual decline in the breakdown voltage and insulation resistance over the aging time. Our findings inferred that the depreciation in quality of PVC cables (insulations and sheaths) is likely due to the chemical stresses which also instigates all other stresses

Detection and Identification of the Series Arc in an Indoor Wiring System

Detection and Identification of the Series Arc in an Indoor Wiring System

Failure Modes and Effects Analysis of Electrical System at Indoor Wires and Wiring Appliances

본 연구에서는 옥내 배선 및 배선기구에 대하여, 통계자료, 관련법, 실태조사 등의 분석을 통하여 그 위험성을 확인하였다. 또한 구성부품을 분류하였고 FMEA 기법 적용이 가능한 신뢰성평가 소프트웨어를 이용하여 고장모드를 발견하고 이를 바탕으로 위험우선순위지수와 중요도를 도출하였다. 옥내 배선 및 배선기구의 구성부품별 중요도는 패널, MCCB/ELB, 커넥터, 스위치, 콘센트, 플러그, 소켓 및 전기배선에서 나타났으며 이중에서 콘센트와 플러그, 전기배선 및 커넥터에서 고장모드가 가장 높게 나타났다. 위험우선순위가 동시에 높은 부품은 콘센트와 플러그, 전기배선 및 커넥터로 중요도와 비슷하게 도출되었다. 특히 콘센트와 플러그 부분에서는 누전 및 접촉불량으로 인한 감전 및 누전화재가 잠재요인으로 나타났으며, 콘센트의 과부하에 의한 과열의 경우도 전기화재를 일으키는 원인으로 작용하고 있고 이 모든 것이 옥내 배선 및 배선기구의 전기재해를 높이는 원인으로 분석되었다.This study analyzed the risks of indoor wires and wiring appliances by looking into statistical data, relevant laws, and actual conditions. In addition, it classified the components to find a failure mode with the use of the reliability evaluation software that can apply the Failure Modes and Effects Analysis (FMEA) technique, and drew a risk priority index and the degree of importance. Regarding the components of indoor wires and wiring appliances, their importance factors were panel, MCCB/ELB, connector, switch, outlet, plug, socket and electric wire, of which outlet, plug, electric wire and connector had the highest failure mode. In addition, it is found that the overheat induced by outlet overload caused an electric fire and increased electric disasters of indoor wires and wiring appliances. The study results are applicable to the fires with the risk of human disaster and the risk of life safety on household items.

전기배선에서 과전류와 포화시간을 입력변수로 갖는 퍼지기반 전기화재가능성 분석

The study is aimed to develop fuzzy logic system that has overcurrent and saturation time as input variable and possibility of electrical fire as output variable by making bad conductor area with physical damage to indoor wiring. Most previous studies focused on thermal characteristics depending on the current size and no study considered the current size and saturation time at the same time. Therefore, the paper made into account current value and saturation time together. To this end, it created bad conductor area half the size of IV conductor (1.6 mm) on purpose and transmit electrical current from 10A to 60A by unit of 2A to find out the thermal characteristics and saturation time for current. Based on the data that came out, the study applied fuzzy logic and established the current and saturation time as input variable and chance of fire as output variable. As a result, the center of area of the system that depended only on the existing current value was 75 while the system that applied both current and saturation time presented the chance of fire at 92. It is found that the chance of bad conductor area and deteriorated insulation of electrical wire had current and saturation time as important variables. The data can be used as basic data like deteriorated wire insulation or operation features of circuit breaker in investigating the cause of electrical fire.

옥내배선에서 과전류와 누전 신호의 상관관계 적용을 위한 지능형 기법 연구

The purpose of this paper is to study the correlation application that electrical fire causes occurs for overcurrent and leakage current signals in the indoor wiring. In the order to purpose, the causes data of overcurrent, or leakage current of electrical fire are drawn out referring to past studies, consulting with experts and experimental data. The correlation application was then applied with fuzzy logic of intelligent technique. To check the reliability and performance of the correlation application, modified center of area(CoA) was adopted to calculate the possibility that electrical fire occurs, whose value was then compared to the results. The chance of electrical fire calculated is higher when two causes of fire are put into the CoA of the correlation application of this paper than that of when each cause is separately put into the CoA. The correlation application developed in this study enables better analysis on possible electrical fire due to overcurrent, or leakage current and provides managers with the possibility of electrical fire so that they can better manage at a time of

A study of modeling of EMTP analysis for indoor distribution line

AbstractDamage to home electric appliances due to lightning surges has recently become more common. The installation of SPDs (surge protective devices) in interior wiring is a countermeasure against damage and is also becoming more widespread after amendment of the regulation on indoor wires in 2005. Past study showed an effective method in which the earth line of the SPD is connected with that of home appliances and is grounded at one place in the home. However, because the methods of installing the distribution line in homes vary, it is difficult to estimate the effect of SPDs in every home, and high‐precision analysis by EMTP for interior wiring and SPD in the home is required. In this study, experiments were conducted with interior wiring and varistors, which constitute SPDs, and this paper reports the results of those experiments and of EMTP analytical models. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 175(4): 24–33, 2011; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21062

A Study on EMTP-Analysis Model for Switch-Board SPD with Gap and Propagation Characteristics of Lightning Surge on Simple Indoor Distribution Line

The numbers of damages of home electric appliances due to lightning surges have recently increased. Installing Surge Protective Devices (SPDs) for indoor distribution line is one of countermeasures against the damages, and is also spreading after an amendment of the regulation on indoor wires in 2005. Past studies have showed that the SPDs installed on the switchboard are effective for protecting all the equipment supplied by indoor distribution lines against lightning strokes.However, it is difficult to evaluate the protective effects of the SPDs against lightning strikes when considering complex indoor wires in houses. Thus, a high-precision analysis method is required to clarify the lightning performance of the SPDs for interior wiring. In this research, experiments were conducted to grasp the protective effects of the SPDs installed on a switchboard against lightning surges invading into a house, and an analysis model by the EMTP was proposed. The calculated results relatively agreed with the experimental results.

병렬아크의 고속차단에 관한 연구

기존의 누진차단기는 병렬아크에 대해서 차단을 실패하거나 차단시간이 길어지는 결함이 있었다. 본 논문에서는 저압 옥내배선 계통에서 벙렬아크를 모의하여 기존 누진차단기의 차단특성을 분석하고, 병렬아크 검출에 적합한 공심형 잔류센서와 신호변환회로를 설계하여 기존 방식의 누천차단기에 적용하였다.<BR> 제안한 방식은 병렬아크의 발생위치와 관계없이 누전차단기를 동작시켰으며, 차단시간은 아크가 발생한 위상에 따라 1.74~8.3[ms]의 범위로 기존 차단기에 비해 약 5배 빠른 특성이다.

A Study of Modeling of EMTP-Analysis for Indoor Distribution Line

The number of damages of home electric appliances due to lightning surges have recently increased. Instllation of SPDs (Surge Protective Device) in interior wireing is one of countermeasures against the damages and is also spreading after an amendment of the regulation on indoor wires in 2005. Past study showed effective mthod, the earth line of SPD is connected with that of home appliances and is grounded at one place at home.However, because the institution ways of the distribution line at each home are various, it is difficult to estimate the effect of SPD at every home, and the high-precision analysis by EMTP for interior wiring and SPD at home is required. In this study, experiments were conducted with interior wiring and varisters which constitues SPD, and this paper report the results by those experiments and EMTP analytical models.

A Study of Distributions of Voltage and Current Caused by Lightning Surges Intruding into Home from Service Wire

Damage of home appliances, such as personal computers and fax machines has a great influence on highly sophisticated information society. Surge protective devices (SPD) are expected to be prevalent because installation of the SPD at a switchboard is recommended in the regulation on indoor wires revised in 2005.In this study, experiments were conducted with a full-scale distribution system and interior wiring in order to clarify lightning response to surges intruding from service wires. The results confirmed that SPD at a switchboard with common grounding wire is effective for protecting home appliances. But in some cases, surge current could propagate into communication lines when the ground wires of SPDs at a switchboard and of a communication appliance are connected each other.

초고속통신망을 위한 구내통신 설로설비의 브릿지 탭의 문제점과 개선 방안

기존 공동주택의 구내통신 선로설비 중의 댁내배선은 대부분 버스 배선 형태의 구조로 아웃렛의 위치에 따라 브릿지 탭(Bridged Tap)이 존재하게 된다. 이 브릿지 탭은 높은 주파수 대역을 사용하는 고속멀티미디어 통신의 특정 주파수에서 반사손실의 특성이 저하되어 선로의 감쇠가 급격히 증가하여 전송성능을 저하시키고 있어 이에 대한 분석이 필요하다. 본 논문에서는 기존 주거용 공동주택의 대표적인 아파트의 구내선로 구조 및 댁내 배선환경을 파악하고, 현업의 구내통신설비를 모델링하여 시험모형을 제작하여 VDSL 서비스 성능을 측정하였다. VDSL 서비스 시 브릿지 탭에 의해 성능에 미치는 영향을 분석하여, 기존 구내통신 선로의 문제점을 파악하고, 향후 초고속 멀티미디어 서비스 수용에 적합한 구내통신 선로의 품질개선 방안을 제시하였다. The position of the bridged tap is determined by that of the outlet in most modern apartments, since most of the indoor wiring utilizes the bus wiring structure when deploying the indoor communication line. These bridged taps deteriorate transmission performance in the specific frequency at the time of high-speed multimedia communication, which uses a high frequency bandwidth, since the duality of return loss worsens and line attenuation increases rapidly. As a result, analysis on this phenomenon is required. In this study, the test model is created by modeling the intercommunication facility of the apartment that is the most representative residential house type, and by understanding the structure and the environment of the indoor wiring. Also, how the bridge tap affects performance is analyzed when the VDSL service is provided, so that problems of intercommunication lines can be identified and methods for improving the proper intercommunication line can be suggested, which is suitable for accommodating high-speed multimedia service of the future.

Thermal Characteristics of Access Cables Composed of Newly Designed Coated Fibers

The changes in fiber strain and fiber loss with temperature are quantitatively evaluated for 0.5 mm UV-coated fiber and three kind of fiber-optic access cables, for dropping and indoor wiring, employing 0.5 mm UV-coated fiber. Measurements of the fiber strain and loss increase are conducted using a quasi-heterodyne interferometer method and a photon-counting optical-time-domain-reflectmeter, respectively, at 1.3 and 1.55μm. From the strain characteristics, the following observations are made: (a) In the temperature range from -40 to 20°C the fiber strain followed the cable strain quite closely, thus maintaining a tight cable structure and (b) from 20 to 80°C, the fiber exhibited a lower strain than the cable strain. Furthermore, no loss increase due to temperature change was observed for the 0.5-mm diameter coated fiber and the three type of optical cables.

Utilization of Holey Fibers with Low Bending Loss

A holey fiber has been developed that has an extremely low bending loss (less than 0.01dB/turn) at a bending diameter of 10mm. Six air holes around the core lower the effective cladding index and as a result those confine the signal light within the core better compared with conventional fibers. The optical characteristics, fiber-joint characteristics, and reliability of this holey fiber were investigated. An optical curl cord developed utilizing the very low bending loss of this holey fiber was found to have characteristics suitable for indoor wiring of FTTH.

Low-bending-loss single-mode fibers for fiber-to-the-home

Recent progress on low-bending-loss single-mode optical fibers for fiber-to-the-home (FTTH) is reviewed. Designing and manufacturing for three types of fibers-a step-index-profile fiber, a trench-index-profile fiber, and a holey fiber-are discussed. The trench-index-profile fibers and the holey fibers are confirmed to be candidates for indoor wiring because of their low bending losses, as well as splice losses.

Low-Bending-Loss and Low-Splice-Loss Single-Mode Fibers Employing a Trench Index Profile

A single-mode fiber employing a trench index profile for indoor wiring is proposed to realize low-bending loss and low-splice loss simultaneously. The designs and the advantages of the fiber over fibers with conventional step index profiles are described. The characteristics of manufactured fibers with trench index profiles are also described. One of the manufactured fibers realizes a bending loss of 0.018 dB/turn at 1550 nm for a bending radius of 7.5 mm, and a splice loss of 0.19 dB at 1550 nm in mechanical splicing to a conventional single mode fiber simultaneously. Other one of the fibers realizes a bending loss of 0.01 dB/tum at 1550 nm for a bending radius of 5 mm, and the splice loss is 0.37 dB at 1550 nm simultaneously. A total loss of a fiber employing the trench index is small and stable against the fluctuation of MFD.

Countermeasures for controlling lightning‐caused overvoltage on indoor wiring with communication line

AbstractOvervoltage generated by lightning is a threat to indoor electrical equipment in our information‐oriented and computerized society. Countermeasures for preventing overvoltage on indoor wiring are demanded. Therefore, we have investigated the effectiveness of some countermeasures, such as low‐voltage arresters, communication line arresters, SPDs, and a common grounding wire, for reducing the overvoltage on indoor wiring with a communication line. In particular, we have studied the effect of the combination of these countermeasures and their layout on controlling the overvoltage, using a full‐scale test distribution line with a customer's facility. The main results are as follows: A common grounding wire installed along the low‐voltage indoor wiring is more effective for reducing the overvoltage on the indoor wiring with a communication line than is one installed under the floor, when the arresters are installed at the panel board. Combination of an SPD and other countermeasures, such as low‐voltage arresters and a common grounding wire, is effective for controlling the overvoltage on the indoor wiring, and the effectiveness of these countermeasures for preventing damage of electrical equipment has been verified by an experiment using actual electrical equipment. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(1): 37–45, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10223

通信線を含む屋内配線における雷過電圧抑制策の検討

Overvoltage generated by lightning is a threat to indoor electrical equipment in our information-oriented and computerized society. Countermeasures for preventing overvoltage on indoor wiring are demanded. Therefore, we have investigated the effectiveness of some countermeasures, such as low-voltage arresters, communication line arresters, SPDs, and a common grounding wire, for reducing the overvoltage on indoor wiring with a communication line. In particular, we have studied the effect of the combination of these countermeasures and their layout on controlling the overvoltage, using a full-scale test distribution line with a customer's facility. The main results are as follows: (1)A common grounding wire installed along the low-voltage indoor wiring is more effective for reducing the overvoltage on the indoor wiring with a communication line than is one installed under the floor, when the arresters are installed at the panel board. (2)Combination of an SPD and other countermeasures, such as low-voltage arresters and a common grounding wire, is effective for controlling the overvoltage on the indoor wiring, and the effectiveness of these countermeasures for preventing damage of electrical equipment has been verified by an experiment using actual electrical equipment. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(1): 37–45, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10223

Indoor Wiring and Lighting

Indoor Wiring and Lighting