Whether you're a contractor or building manager, it is important to keep Class 2 compliance in mind when retrofitting or creating new construction with low voltage LED lights and systems. The National Electric Code (NEC) requires that low voltage power supplies and electrical wiring be Class 2 compliant. The code was created to prevent electrical fires and shock.
Inspeccions: qui les necessita i com funcionen
If you are creating new construction or adding major modifications, you will most likely require an inspection. New construction requires a work permit that must be obtained from a local safety or electrical inspector. Some small jobs may not require a permit but it is in your best interest to get a safety inspection to avoid any unintended problems. For example, if you re-wire a kitchen or basement without having it inspected and then try to sell the house, an inspector may ask you to tear the walls down to check the wiring. Also, if faulty wiring that wasn't inspected starts an electrical fire, your insurance company might challenge the claim.
To begin the permit process, you'll need to present a detailed wiring diagram of your project to your local inspector. Once a work permit is granted, the inspection consists of two visits: the 'rough-in' inspection and the 'final' inspection. The rough-in inspection consists of checking that all wiring is properly installed before any switches, fixtures, insulation and walls are added. For low-voltage installations, this is when the inspector will specifically check to see if the wiring is Class 2 compliant. Basically, the skeleton of the installation will be reviewed to see if the correct gauge wire is installed and harnessed correctly, as well as other measures.
Un cop superada la-inspecció aproximada, podeu completar la instal·lació amb aïllament, parets, interruptors i accessoris abans de la inspecció final. Quan comproveu llums i sistemes LED de baixa tensió, l'inspector comprovarà si les fonts d'alimentació són accessibles i compleixen la classe 2. També comprovaran si els accessoris estan aprovats per un Laboratori Nacional de Proves Reconegut (NRTL), com ara Underwriter Laboratories (UL) o Intertek (ETL).
Una vegada que l'inspector aprovi que el projecte compleix els estàndards professionals, podeu començar a utilitzar els vostres nous circuits amb seguretat i confiança en el compliment. Et preguntes què pots fer per assegurar-te que el teu projecte sigui aprovat? A continuació, repassem tots els components del projecte d'il·luminació.
Llista de verificació de compliment de la classe 2
Poder
Power supplies convert the 120V power into low voltage 12V or 24V power. For power supplies to be Class 2 compliant, 12V DC drivers must be 60W and under and 24V drivers must be 96W and under. Power supplies that comply with the Class 2 regulation are always marked or labeled as so.
Also for NEC compliance, Class 1 circuits (up to 600V) and Class 2 circuits must be separated. To pass inspection, a junction box must be installed to encapsulate a 120V AC wire connection to a 12-24V DC power converter (driver). Junction boxes provide a safe, grounded fireproof enclosure, preventing wire nuts from coming loose and causing a short and possible electrical fire. This Lo-Caixa de connexió Pro is one example of how to separate high and low voltage wiring within the same enclosure.
For large projects such as kitchen remodels, office upgrades or new commercial spaces, a large amount of power is often required. In this case, you have two options: You can install several 60W drivers, or you can install a high wattage multi-tap driver such as the Controlador de classe 2 de 12 V 300 watts. This driver contains 5 separate 60W outputs, and each of the outputs has its own circuit breaker so in the case that one of them experiences a surge, the others will not be affected. It's like having several drivers and junction box in one unit, and is a more affordable and easier to install solution than using several separate 60W drivers. Only one switch will control all outputs, so you do not need multiple switches unless you need a section of lighting with an individual control such as a dimmer.
Cablejat
La majoria del cablejat electrònic està recobert d'un aïllament a base de goma-per garantir la prevenció de corrosió i curt{1}}circuits. Això és prou segur per a instal·lacions interiors amb endolls de paret, per exemple, per alimentar un llum a la vostra sala d'estar o una consola de videojocs. Però per a una instal·lació permanent de cables durs-, s'han de prendre més precaucions per complir la Classe 2.
Most wire you see at the hardware store isn't rated for permanent installation and cannot be installed inside walls, under floorboards, or as a structural component of a building. For example, for an installation where you would want to hide wires behind a wall, the wires could be surrounded by insulation, creating a warmer environment. The wires could crack or melt, leading to sparks or fires. Class 2 In-Wall Rated Wire provides an extra layer of installation that is more resistant to cracking or melting, and is approved by the NEC to be installed inside walls.
Il·luminació
As we mentioned earlier, all low-voltage lighting fixtures must be certified by an NRTL to pass inspection. To verify that a product is UL or ETL listed, check the product details in the lighting company's catalog or website. If you can't locate the information you need, you may want to contact the manufacturer directly. For extra precaution, you can look up the number listed on the official websites for UL and ETL to make sure the certification is authentic. The best way to search the Directori de certificacions en línia UL is to use the E-file number. For the Directori ETL, cerqueu amb el nom de l'empresa o el número i el nom del producte.
Recursos addicionals
Want to dig deeper? The Associació Nacional de Protecció contra Incendis (NFPA) provides more detailed information about Class 2 compliance, who it impacts and why it is important. You can buy the latest NEC handbook through the NFPA website or even on Amazon. You may also contact your local inspector on how to best prepare your project for inspection.
A punt per inspeccionar
Ara que ja sabeu com preparar la vostra instal·lació de baixa-tensió perquè els llums LED, les fonts d'alimentació, les connexions i el cablejat compleixin la Classe 2, ja esteu preparat per a la inspecció. Pots estar segur que la inspecció es farà sense problemes i que la instal·lació es mantindrà segura durant els propers anys.
