505.7 Special Precaution
Informational Note No. 1: It is important that inspection authorities and users exercise more than ordinary care with regard to the installation and maintenance of electrical equipment in hazardous (classified) locations.
Informational Note No. 2: Low ambient conditions require special consideration. Electrical equipment depending on the protection techniques described by 505.8(A) may not be suitable for use at temperatures lower than -20°C (-4°F) unless they are identified for use at lower temperatures. However, at low ambient temperatures, flammable concentrations of vapors may not exist in a location classified Zones 0, 1, or 2 at normal ambient temperature.
Table 505.7(D) Minimum Distance of Obstructions from Flameproof "d" Flange Openings
|Gas Group||Minimum Distance|