Hazardous Locations - Section 18 Flashcards
Where are rules for older Class and division style installations found?
Annex J18 in appendix J.
What is the only acceptable wiring method for zone 0 locations?
Intrinsically safe (ia).
What would be the zone classification for an area where during normal operations explosive dust and fibre are present.
Zone 20.
What would cause equipment to run hotter than normal in a zone 20,21 or 22 environment?
A dust layer (thermal boundary).
When entering an explosionproof box with a cable, are seals required?
Yes, so that the cable does not allow the flame path inside.
When analyzing section 18, what is your most valuable resource?
Appendix B.
If a method of protection given is ‘ed’ or ‘de’ is the box explosion or flame proof?
Likely not, when the combination ‘de’ is given, usually the enclosure is only e rated, where the components are ‘de’ rated.
What metric exposes a zone 0 or 20 location?
Gas or dust is present for 1000 hours or more per year.
Would a temperature code be given on a dust tight ex enclosure?
No, in dusty environments, the surface temperature of a box is given in degrees C.
Why are conduit seals used in zone 1 locations?
So that the flame will not travel through the conduit system.
What is ingress protection?
The level of protection guarding against unwanted dusts or fluid of an enclosure or fitting.
What could occur if a gouge existed between the mating surfaces of an explosionproof box?
The flame path would be compromised and serious explosions could occur.
Explosion proof receptacles contain an internal switch, why?
So that power is disconnected safely before the cord is allowed to be removed.
In general, when using a flexible cord in hazardous locations it should be?
Of the extra hard usage type.
