H1 Flashcards
List the major advantages a single-phase, three wire system offers
two voltages
improved safety by grounding the neutral
reduced wire size due to smaller conductors
service conductors are first ran to a
kilowatt-hour meter
Describe: combination panel
the main breaker that the service conductors are hooked to is separated form the cct breakers by a barrier
Why must the neutral in a three wire system never be fused
if fuse opens then
can create unequal division of voltage across the loads
creates a shock hazard at the break
list two reasons that the transformer and the power panel are grounded
To limit the hazard of a shock to 120V
to provide a path to trip the cct breaker in the case of a ground fault
the supply conductors are supported by
an Emily knob
meter base must be installed
1.5m to 1.8 meters above finish grade
spool insulator and rack must be mounted
150mm to 300mm below the weather head
what is triplex
neutral supported cable that has two aluminum conductors wrapped around a bare steel-reinforced aluminum conductor also called a messenger
Table 36A
The supply authority limits the triplex to a span of
30m
The consumer is responsible to install the service equipment up to and including the
drip loops but not the meter its self
Supply lines usually are installed within
1 m of the corner of the building
explain how underground service conductors are installed
installed at least 900 mm deep (table 53)
3 inch conduit
bedded in sand
have 100m warning tape installed above the pipe
What is the reasons to ground overhead and underground service at the transformer and at the building
protect life and property from electric shock
limit wiring to 150v to ground
open cct breakers in the case of a ground fault (bonding)
what must be used for grounding the neutral conductor
6 AWG copper conductor hooked to
conductive water main system
metal casing of a well
artificial grounding electrode
