{"id":2692,"date":"2024-09-25T17:59:56","date_gmt":"2024-09-25T17:59:56","guid":{"rendered":"https:\/\/crp.trb.org\/acrpwebresource20\/rules-for-safety\/"},"modified":"2024-09-25T19:03:54","modified_gmt":"2024-09-25T19:03:54","slug":"rules-for-safety","status":"publish","type":"page","link":"https:\/\/crp.trb.org\/acrpwebresource20\/rules-for-safety\/","title":{"rendered":"Rules for Safety"},"content":{"rendered":"
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\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\"09-22-airfileld-electrical-banner\"\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t
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Rules for Safety<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t
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It is very important that airfield series circuits be de-energized and verified prior to working on them. Even simple tasks such as re-lamping or removing fixtures with the circuit energized can be extremely hazardous because of unseen dangers. One such danger is a fault between the primary and secondary windings of the isolation transformer feeding the light, which exposes the worker to the full voltage<\/span> present on the primary wiring. See AC 150\/5340-26C<\/a> 2.4.3.a-b for a detailed description of how this happens.<\/p>

Another hazard is the high open-circuit voltage<\/span> present at the secondary of the isolation transformer. Airfield lights work on low voltage<\/span> from the secondary of the isolation transformer; however, when the light is removed or burns out, the transformer secondary is “opened,” which can cause the transformer to produce as much as 200 volts to the lamp connection point.<\/p>

Breaking a live connection on an airfield series circuit creates an “open circuit” and is a dangerous and potentially deadly situation. When the live connection is broken, the circuit amperage drops. In an attempt to bring the amperage back up to the proper level, the constant current regulator<\/span> instantaneously sends the voltage<\/span> to its maximum level, which can reach nearly 10,000 volts. At that voltage<\/span> it is very possible that it will drive the circuit through the worker’s body which will most likely be fatal.<\/p>

Lastly, beware of induced voltages on wires that run in the same conduit as energized wires. Circuits with pulsing loads such as runway guard lights<\/span> or strobes are especially prone to inducing voltages on other conductors.<\/p>

Working on airfield series lighting circuits does not necessarily have to be hazardous if the proper safety practices and procedures are followed:<\/strong><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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  1. Strictly and habitually follow the safety rules listed under “Basic safety rules to remember when working with airport lighting circuits.”<\/li>
  2. Require that all maintenance workers, especially new employees, are properly trained in electrical safety and are familiar with the particular system of your airport. New workers should shadow experienced workers until they are qualified and competent with the system.<\/li>
  3. Always have at least two electricians when maintenance is conducted on a high voltage<\/span> circuit, regardless of energized status, with at least one having a thorough knowledge of the airport’s high voltage<\/span> circuits.<\/li>
  4. Do not do maintenance work on live circuits.<\/li>
  5. Always use Lock-out\/Tag-out (LOTO) with all workers placing their own personal lock on the de-energization means.<\/li>
  6. Verify that the circuit you have locked is actually the circuit you will be working on. Attempt to energize the circuit by all means, such as Airfield Lighting Control and Monitoring System or pilot-activated radio control. Energize all circuits in the vicinity of your work to verify the boundary of your circuit, then lock out all circuits in the vicinity of your work.<\/li>
  7. Use the proper tools for the job:
    1. Always use a true RMS clamp-on ammeter to test for current before breaking any primary voltage<\/span> connections and test your ammeter on a known live circuit often.<\/li>
    2. Do not check voltage<\/span> with a common voltmeter on series constant current circuits. Extremely high voltages may be present which could destroy the meter and cause injury or death. If you want to know the voltage<\/span>, use the regulator<\/span>’s internal voltmeter.<\/li>
    3. Do not rely on a proximity voltage<\/span> meter (also known as a volt tick) to verify de-energization. Because of the way voltage<\/span> drops in an alternating current series circuit, there will be no detectable voltage<\/span> in the center of the circuit even though current is still flowing in the wire.<\/li><\/ol><\/li>
    4. Beware of transition zones where one circuit ends and another begins. Is the light off because you have locked the circuit, or does it have a burned-out lamp and is on the adjacent energized circuit?<\/li>
    5. Do not blindly trust circuit labels. It is not uncommon for circuits to be mislabeled in a light can.<\/li><\/ol>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t
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      Basic safety rules to remember when working with airport lighting circuits:<\/h5>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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