![]() Relays and ducting can be identified if specified and relevant to the application. Wires are typically marked with self-laminating vinyl labels or printable heat shrink tubing. If the overall SCCR is a high-fault rating, an additional label needs to be applied with the language shown in Fig. If there are several items within the panel, such as circuit breakers, a motor control unit, and a starter, the lowest rated SCCR of the device within the control panel must be used as the controlling factor for marking the panel. If the overall SCCR is a high-fault rating, an additional label needs to be applied with the following language. Note: The SCCR label is also required, even if the shop is non-UL-approved. When a UL inspector arrives, he or she will expect to see the associated SCCR label applied in conjunction with the UL508A label. Usually, the shop pays an annual fee to UL to maintain the listing. If the control manufacturer is a UL 508A shop, it’s certified by UL to apply a serialized label that reads “UL 508A” with a unique serial number supplied by UL. Part of the changes were driven by the fact that as more companies used industrial control panels, there was a significant increase in the misapplication of control products and related equipment.Īrticle 409 also impacts the way equipment is designed and constructed so the entire panel - and all components inside - meet a defined short circuit current rating (SCCR) for the application and is marked with the appropriate SCCR. Until that time, industrial control panels had been installed based upon general electrical requirements from several different areas in the NEC. Article 409 of the NEC provides the designer/installer and enforcement authorities with the minimum requirements to facilitate the safe installation and inspection of industrial control panels. However, some additional requirements are worth noting. Industrial control panels require much of the same labeling as described for the switchboards and panelboards. After starting our discussion at the service entrance of the building and moving through equipment like motor control centers, feeders, switchboards, and panels, it’s time to turn our attention to industrial control panels and industrial automation equipment. We also noted how labeling has become a critical component of ensuring worker safety and reducing client liability. I would argue that the fused spur should also be fed from the KNX control panel, but this is not always possible.In part one of this two-part series on code-compliant electrical equipment labeling, we recognized that OSHA is moving toward more citations, greater penalties, and more frequent inspections. It is not uncommon in a plantroom to have the permanent supply to a device, such as a pump, to be fed via a fused spur but the switched live to come from the KNX panel. ![]() If our panel, a module, or indeed a device is being fed from more than one supply, then we must warn people with a ‘More than one point of isolation’ sticker. There are times when modules may be fed by more than one breaker due to current limitations or practical design considerations, such as a half of a module feeding downstairs and the other upstairs. Prove that the approved voltage indicator or test lamp is functioning correctly.Identify the source(s) of supply using an approved voltage indicator or test lamp.Obtain permission to start work (a permit may be required in some situations).Unless, of course, you have an electrical arm to your business, in which case you absolutely do.Įxample of a well-labelled KNX panel (image source: KNX Association).Įlectrical safe isolation and multiple points of isolationĪny competent electrician will be familiar with the practice of safe isolation. I’m sure everyone would agree that they’d prefer not to have other trades poking about in our panels, but equally, we don’t want to be called out every time a lighting driver has to be changed or a fused spur blows its fuse. There is a notable example of panel labelling in a recent KNXtoday article. ![]() Without this, people are simply guessing and may inadvertently turn on something that is part of a sequence of devices, for example, the manifold pump gets turned on but not the manifold valve, causing the pump to be under stress pumping against a closed valve until the next time the program triggers those devices on or off. Can the electrician or homeowner manually turn on or test the circuit? In providing this information, you eliminate the need for control via a wall switch or any form of programming, therefore providing the means by which the electrician can prove that they have successfully rectified the problem. The second part of this puzzle is to provide information about where on a particular module the circuit is connected.
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