National Electrical Code Top Ten Tips: Article 669 -- Electroplating
Electroplating has been around a long time and products made with this process are ubiquitous. Every time you see a chrome bumper, you are looking at an electroplated object. That chromium finish was put on the steel bumper by a process called electrolytic deposition or electroplating. Silver is another metal that's commonly electroplated, but not onto car bumpers. Any shop or factory that has an electroplating operation must comply with additional EPA and OSHA requirements.
- Article 669 applies to the installation of the electrical components and
accessory equipment that supply the power and controls for electroplating, anodizing, electropolishing, and electrostripping [669.1].
- Article 669 refers to electroplating, anodizing, electropolishing, and electrostripping all as electroplating. That is for simplicity's sake, not for any technical reason. In a given shop or factory, the equipment may have a different name as well. If it's using an electric means of depositing a metal finish such as chromium onto another metal such as steel, then for NEC purposes it is electroplating [669.1].
- Any equipment used for electroplating must be identified for such service [669.3]. This seems obvious, but suppose you are asked to install a machine at a small shop. The owner has rigged up his own electroplating machine by modifying a machine used for another purpose. The owner theoretically could identify this machine for use as an electroplating machine. But if something goes wrong, what will his insurance company say? Does the manufacturer of the previously unmodified machine have any liability? The testing lab (e.g. UL) certification has been nullified, so no that manufacturer stands little chance of being found liable. But who installed that machine? There's the party most likely to endure a costly lawsuit. Make sure before installing this equipment that it has been properly engineered and identified by some qualified party or authority for that use. If, for example, a machine rebuilding firm engineered this equipment that firm is in the business of building new equipment from old and has the expertise to do so. But Joe Blow Jury Rigger is not and does not.
- The branch circuit supplying the equipment must have an ampacity of at least 125% of the total connected load [669.5].
- Section 669.5 also says that busbars supplying this equipment must have an ampacity that conforms to the requirements of 366.23. But Article 366 is about auxilliary gutters. Those are a form of raceway, not a conductor (366 comes right after 362, which is for electrical nonmetallic tubing). So is this an error? No, read carefully. The busbar ampacity must be comply the limits for bars stated in 366.23; those limits are not for the gutter, but for the bars. So, for example, bare copper bus bar in a sheet metal auxilliary gutter can't exceed 1000A/ square inch.
- If the system does not exceed 60V of direct current, insulated conductors can be run without insulated support, but only if they are protected from physical damage [669.6(A)]. Please note that insulated supports come in handy for protecting insulated conductors from phyical damage.
- If the system exceeds 60V of direct current, insulated conductors can be run with insulated support, but only if they are protected from physical damage [669.6(B)].
- If the system does not exceed 60V of direct current, you can use bare copper or aluminum conductors if you support them on insulators [669.6(A)].
- If the system exceeda 60V of direct current, you can use bare copper or aluminum conductors if you support them on insulators and guard them against accidental contact up to the point of termination [669.6(B)].
- If there's more than one power supply to the equipment, you must provide a disconnecting means on the dc side of each power supply [669.8(A)]