Circuit brakers Flashcards
Where is the amperage rating of a circuit breaker?
On the handle
two types of automatic overload devices that are normally used in electrical circuits to prevent fires and the destruction of thee circuits and its associated equipment
Fuses and circuit breakers
Circuit brakers are classified according to given current ranges.each group is classified by the largest ampere rating of its range.does groups are?
15a-100a 125a-225a 250a-400a 500a-1000a 1200a-2000a
Two organizations that both test and list devises?
UL And Canadian standards association (CSA)
Has and interrupting rating of 65,000a symmetrical at 240 VAC.
FH-type circuit brakers
Which NEC article Cover overcurrent protection?
NEC 240
Standard interrupting capacity circuit breaker can by identified by
Their black operating handles and black printed interrupting rating labels.
GFCI UL defines a class A device as one that will trip when a fault current to ground is?
6mA or more
In residential applications the available fail current is seldom higher than?
10,000A
Nonfeedthrough GFCI offer protection?
Only at the point of installation
Single-element fuses?
Have a very high speed of response to overcurrents
Fuse marking must be contain?
- Ampere rating
- voltage rating
- interrupting rating If over than 10,000
- Current limiting where applicable
- the name or trademark of the manufacturer
When sizing fuses for a given application use schematics such as?
A single-line schematic will surffice
Coordination
Selective coordination is the selection of over current devices with time/current characteristics.
At currents below a threshold of about 1000A the current-limiting circuit breaker performs in a manner similar to ?
Conventional thermomagnetic circuit breaker.
