A1 LT13 Flashcards
What happens if too much heat is present in a circuit application?
Insulation may melt or burn
What is cambric known for?
Hygroscopic and absorbs moisture.
Why should insulation be appropriate for its location?
Moisture and toxic elements can cause insulation deterioration
What are the types of rubber commonly used as insulation?
Natural rubber and silicone-based rubber.
What is a material used in a strong, moisture-proof sheath for carrying heavier current?
Copper
What are rubber compounds used for?
Flexibility and abrasion resistance
Why does most electrical wiring circuits look complicated?
Multiple wires at any one point
What characteristics must be kept in mind when using cables?
Cold flow, warmer plastic flows faster
How are conductors marked for identification?
Coloured insulation or labelled marker
How does high temperatures affect insulation life expectancy?
Reduced by one-half for every 10C beyond normal rating
How can polyvinylchloride (PVC) be identified?
Flame test - melts, drips, burns, self-extinguishes
What does a green wire indicate?
Bonding conductor
What is the operation voltage limit for PVC insulation according to the Code?
600 V AC
What do red, black, or blue wires typically indicate?
Live or hot
What is the maximum conductor temperature allowed for PVC insulation?
60C
What is the surface marking for cross-linked polyethylene as required by the Code?
XLPE or X LINK
What happens to thermosetting materials when they are heated?
They harden
What properties are improved in thermosetting materials when they harden?
Electrical, thermal, mechanical
What is mica used for?
High temperature applications like toasters and irons.
Which colours are reserved for specific applications according to the Canadian Electrical Code?
White or natural grey
What are some applications of enamel as an insulating material?
Meter coils, transformers, motor windings
What are thermoplastic materials’ properties when heated?
Soften
In what cases does a white wire not indicate a neutral conductor?
Switch loops
What happens to thermoplastic materials when they cool?
Harden
What are some trade names for PVC?
Flameseal, Flamenol
Which PVC insulation type is suitable for direct burial in the ground?
TWU
How is cross-linked polyethylene affected by cold once installed?
Not affected
What does a white wire indicate in a circuit?
Neutral conductor
What happens if you stretch cambric insulation too tightly?
Varnish film may be broken or weakened.
