1. DASAR-DASAR KESELAMATAN KERJA LISTRIK Oleh: Drs. Suwito SMK NEGERI 1 SINGOSARI PEMERINTAH KABUPATEN MALANG DINAS PENDIDIKAN SMK NEGERI 1 SINGOSARI (Sekolah Bertaraf Internasional) Jalan Raya Mondoroko No. 3 Singosari Telp. (0341) 458138 Fax. 458139 Web Site : http://www.smkn1sgs.com Email : smkn1_sgs@yahoo.com smkn1_sgs@yahoo.com

2. BAHAYA LISTRIK Bilamana anda bekerja dengan alat bertenaga listrik atau instalasinya terdapat bahaya, terutama sengatan arus listrik

3. BAHAYA LISTRIK Seseorang dapat terkena bahaya listrik di rumah. Pekerja terkena sengatan arus listrik di tempat kerja yang disebabkan karena peralatan, bahan kerja, tergesa- gesa dan udara terbuka. Resiko besar juga diderita karena pekerjaan menggunakan peraltan bertenaga listriks.

4. Penelitian Keselamatan Kerja Listrik Penyebab kematian karena listrik menduduki ketiga di tempat kerja dengan usia antara 16- dan 17 tahun, setelah kecelakaan karena kedaraan bermotor. Kematian karena arus listrik 12 % di semua tempat kerja, satu diantaranya pekerja muda

5. Gambar pekerja yang dapat meninggal jika bekerja tanpa keselamatan kerja

6. Bagaimana sengatan listrik dapat terjadi? Sengat listrik dapat terjadi bila terdapat arus yang mengalir pada tubuh manusia. Arus akan melewati tubuh dengan berbagai situasi. Sewaktu-waktu anda tersengat karena beda potensial dua penghantar, arus melewati diantara keduanya

7. lanjutan Kebanyakan kabel instalasi rumah 220 volt berwarna biru dan merah/hitam/kuning dan ground berwarna loreng hijau-kuning. Ground sering dihubungkan dengan kawat tembaga ketanah, atau pipa air terbuat dari logam logam.

8. Gambar warna kabel netral, fasa dan ground

9. Box logam yang digroundkan

10. Periksalah rangkaian untuk meyakinkan ada tidaknya sumber listrik sebelum bekerja.

11. Tabel Sengatan arus listrik dengan pengaruh pada tubuh manusia. 1mA. Hanya merasa geli tidak menyenangkan. 5mA. Sedikit merasa kejutan.menganggu, tetapi tidak pinsang. Kebanyakan orang dapat melepas genggaman.Bagaimanapun kuatnya gerakan tanpa disengaja dapat menyebabkan cidera 6-25mA. Kejutan kesakitan, kontrol otot hilang. Tahap ini arus pembekukan dimulai, tidak mungkin melepas gengaman

12. Lanjutan 50-150mA. Kejutan kesakitan hebat, pernafasan tertahan, beberapa otot mengkerut. Otot flexor menahan, otot extensor menyebabkan kuat mendesak kesamping. Dimungkinkan meninggal 1.000 – 4.300mATerjadi bilik jantung memompa darah tidak berirama. Otot mengkerut, terjadi kerusakan syaraf. Mungkin meninggal 10AJantung tertahan dan terjadi kebakaran serta kematian Sumber: Terjemahan dari National Institute for Occupational Safety and Health, 2002.

13. Menghitung arus listrik yang mengalir pada tubuh Jika kulit kering menunjukkan tahanan 100,000 ohms, berapa arus yang mengalir. Apa yang terjadi pada tubuh manusia Bagaimana dengan kulit basah yang mempunyai tahanan hanya 1,000 ohms ?.

14. Bor bertenaga dengan digunakan 30 kali dengan beban penuh akan dapat membahayakan.

15. Gambar tangan yang terbakar

16. Lengan terbakar karena saluran tegangan tinggi.

17. Tingkat bahaya karena sengatan arus listrik tergantung dari : Banyaknya arus yang mengalir ke tubuh (amount of the shocking current through the body), Lamanya arus yang mengalir (the duration of the shocking current through the body ), dan Jalan aliran arus yang mengalir ke tubuh (path of the shocking current through the body).

18. Burns Caused by Electricity The most common shock-related, nonfatal injury is a burn. Burns caused by electricity may be of three types: electrical burns, arc burns, and thermal contact burns. Electrical burns can result when a person touches electrical wiring or equipment that is used or maintained improperly. Typically, such burns occur on the hands. Electrical burns are one of the most serious injuries you can receive. They need to be given immediate attention. Additionally, clothing may catch fire and a thermal burn may result from the heat of the fire.

19. continued Arc-blasts occur when powerful, high- amperage currents arc through the air. Arcing is theluminous electrical discharge that occurs when high voltages exist across a gap between conductors and current travels through the air. This situation is often caused by equipment failure due to abuse or fatigue. Temperatures as high as 35,000°F have been reached in arc-blasts.

20. Contact electrical burns. The knee on the left was energized, and the knee on the right was grounded.

21. There are three primary hazards associated with an arc-blast. (1) Arcing gives off thermal radiation (heat) and intense light, which can cause burns. Several factors affect the degree of injury, includ- ing skin color, area of skin exposed, and type of clothing worn. Proper clothing, work distances, and overcurrent protection can reduce the risk of such a burn.

22. continued (2) A high-voltage arc can produce a considerable pressure wave blast. A person 2 feet away from a 25,000-amp arc feels a force of about 480 pounds on the front of the body. In addition, such an explosion can cause serious ear damage and memory loss due to concussion. Sometimes the pressure wave throws the victim away from the arc-blast. While this may reduce further exposure to the thermal energy, serious physical injury may result. The pressure wave can propel large objects over great distances. In some cases, the pressure wave has enough force to snap off the heads of steel bolts and knock over walls.

23. continued (3) A high-voltage arc can also cause many of the copper and alu- minum components in electrical equipment to melt. These droplets of molten metal can be blasted great distances by the pressure wave. Although these droplets harden rapidly, they can still be hot enough to cause serious burns or cause ordinary clothing to catch fire, even if you are 10 feet or more away.

24. This death could have been prevented if the following precautions had been taken : Before doing any electrical work, de-energize all circuits and equipment, perform lock-out/tag-out, and test circuits and equipment to make sure they are de-energized. The company should have trained the workers to perform their jobs safely. Proper personal protective equipment (PPE) should always be used. Never use aerosol spray cans around high- voltage equipment.

25. arc-blast.

26. Electrical Fires Electricity is one of the most common causes of fires and thermal burns in homes and workplaces. Defective or misused electrical equipment is a major cause of electrical fires. If there is a small electrical fire, be sure to use only a Class C or multi- purpose (ABC) fire extinguisher, or you might make the problem worse. All fire extinguishers are marked with letter(s) that tell you the kinds of fires they can put out. Some extinguishers contain symbols, too.

27. Electrical Fires

28. The letters and symbols are explained below (including suggestions on how to remember them). A (think: Ashes) = paper, wood, etc. B (think: Barrel) = flammable liquids C (think: Circuits) = electrical fires

29. This extinguisher can only be used on Class B and Class C fires.

30. This extinguisher can only be used on Class A and Class C fires.

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