Protectors of Conductors (From Mechanical Damage) Flashcards
(26 cards)
Two types of conduit (flex)
green field (hollow) BX (Pre-wired)
If you cut the end of conduit what must be done?
an anti-short bushing (red head) must cover the cut end
Conduit must be supported at least every __ ft
At least every 4 1/2 ft
Conduit must be supported at least __ inches within a box
12 inches
How many feet of conduit can be unsupported leading to rotating machinery
3 ft
EMT
Electrical metallic tubing
All ends of EMT must be ____
Cut square and reamed
EMT must be supported at least within every __ft
10 ft
EMT must be supported within __ ft of a box
3 ft
Max bends between a box and pull fittings
360°
Electrical boxes are also referred to as what?
Junction boxes
Junction boxes must always be what?
Covered and supported
What must you do to knock out holes in the electrical box
Must block with knockout covers
Maximum over current protection for 14 g wire
15 Amps
Maximum over current protection for 12 g wire
20 Amps
where must a switch be placed in a circuit
on the hot leg not on the return
what are OHMS?
measurement of resistance to flow
when a switch is closed what will the ohms meter read
0 Ω
if a switch is open what will the ohms read
∞ Ω or OL
to check voltage you must
connect to the line and neutral and if all is good next connect to the load and neutral
you must always have a __ in a circuit
fuse or circuit breaker
Oiler Burners Have a _________ switch in case of emergencies
emergency
what are the rules for emergency switches
must be the highest switch must not be any higher than the first floor in plain sight and clearly marked markings must correlate with switch cannot be in the same room as the boiler
rules for thermal switches
must be placed directly above the burner
no higher than 6ft above the boiler
open at 165° f
