Discontinuous enclosures

Figure 31.5(b) Cross-sectional view of an iPB with insulated (discontinuous) enclosure illustrating busbar-supporting arrangement (Courtesy Best Crompton)... 

Separators for air and material should be located outside the building, have lightning protection, and be electrically conductive and bonded. They should be made of noncombustible materials and equipped with filters of low-hazard or flame-retardant substances in metal enclosures. Material discharge outlets should have positive choke devices. Exhaust air should be directed outdoors or recirculated into the pneumatic system. Sight glasses are not recommended as routine. If necessary, they must be noncombustible, rated for the appropriate pressure, sealed, and installed without internal surface discontinuities. 

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