The harmonization of UL 508 with IEC 60947 will lead to a gradual transition to a new sequence of UL standards for Switchgear and Controlgear, UL 60497. Some existing users of the UL 508 normal marvel what the most applicable wiring methods are. The standard gives many various options to accommodate a range of building requirements. This Wire Wisdom addresses the present options and outlines the changes for the new standards.
Area Wiring – Power Circuits
Wiring between the branch circuit supply and the management panel should be accomplished in accordance with the native electrical code, which is often some variation of the NEC (Nationwide Electrical Code). However, UL 508 clearly allows the usage of portable cord for cabinets which are portable or mobile with the usage of a hand truck or forklift, where there are no other provisions for conduit or permanent connection to the building. The type of twine permitted is a hard service or junior hard service wire reminiscent of an SO or SJO (or different related variation) that terminates in a listed attachment plug. For more info on listed and recognized components, see UL.com.
Subject Wiring – Management Circuits
Area wiring types are once once more decided by the local authority having jurisdiction, usually referencing the NEC, and once more there is a provision for connection of discipline management wiring utilizing cords. Distinctive to regulate circuits are the number of different types, rankings, styles and configurations of connectors that may be used to facilitate connection to the enclosure for quick disconnection or environmental sealing.
Wiring within the Panel – Power Circuits
There are primary things to consider relating to wiring within the panel: what type of wiring to make use of, and find out how to apply it. The present and new standards address the types of wire permitted. To generalize, they’re UL listed thermoplastic or thermoset insulated building wire types, UL acknowledged wires, machine tool wires, and welding belden cable cross reference.
Usually speaking, customers want the more versatile wires resembling MTW or welding cable for energy circuits as they’re simpler to route and facilitate improved cable management inside the cabinet. Routing, fastening, terminating, splicing, and sizing necessities are all detailed within the standards. Of specific interest is the requirement that power conductors shall not be smaller than 14 AWG.
Wiring within the Panel – Management Circuits
Management wiring can be any of the wiring methods allowed for power circuits within the panel with the addition of power-restricted circuit cable corresponding to Type PLTC, CL2, or CL3 and communication cable such as types CM, CMR or CMP. Control circuits are distinctive in that many controls now use industrial networking cabling technology. Because of this, it is important that the cabling within the panel maintains the signal integrity. In such cases, it is usually vital to make use of specialty cabling between the cabinet entrance point and the top device.
Many of the cables wanted for this activity are available with a PLTC or CM rating. Because of the sheer quantity of control wiring that may be present, thin walled, flexible AWM (appliance wiring material) is often used. It’s inexpensive, simple to terminate, available in a wide range of colors and may be customized ordered with many alternative identification methods.