Hazardous Locations - Section 18 Flashcards

1
Q

Where are rules for older Class and division style installations found?

A

Annex J18 in appendix J.

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2
Q

What is the only acceptable wiring method for zone 0 locations?

A

Intrinsically safe (ia).

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3
Q

What would be the zone classification for an area where during normal operations explosive dust and fibre are present.

A

Zone 20.

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4
Q

What would cause equipment to run hotter than normal in a zone 20,21 or 22 environment?

A

A dust layer (thermal boundary).

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5
Q

When entering an explosionproof box with a cable, are seals required?

A

Yes, so that the cable does not allow the flame path inside.

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6
Q

When analyzing section 18, what is your most valuable resource?

A

Appendix B.

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7
Q

If a method of protection given is ‘ed’ or ‘de’ is the box explosion or flame proof?

A

Likely not, when the combination ‘de’ is given, usually the enclosure is only e rated, where the components are ‘de’ rated.

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8
Q

What metric exposes a zone 0 or 20 location?

A

Gas or dust is present for 1000 hours or more per year.

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9
Q

Would a temperature code be given on a dust tight ex enclosure?

A

No, in dusty environments, the surface temperature of a box is given in degrees C.

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10
Q

Why are conduit seals used in zone 1 locations?

A

So that the flame will not travel through the conduit system.

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11
Q

What is ingress protection?

A

The level of protection guarding against unwanted dusts or fluid of an enclosure or fitting.

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12
Q

What could occur if a gouge existed between the mating surfaces of an explosionproof box?

A

The flame path would be compromised and serious explosions could occur.

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13
Q

Explosion proof receptacles contain an internal switch, why?

A

So that power is disconnected safely before the cord is allowed to be removed.

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14
Q

In general, when using a flexible cord in hazardous locations it should be?

A

Of the extra hard usage type.

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