Electricial Rigging Flashcards
Electrical code requirements for labeling single conductors
6 inches of colored electrical tape
Ground knot label
two strings tied twice
Neutral Knot label
two strings tied once
Blue knot label
no knots “blue sky clear”
Red knot label
one string tied once “one red eye”
Black knot label
one string tied twice “two black eyes”
Label each distribution box with… (3)
1) power source
2) Type of power
3) Intended function of the circuit
identifying two different kinds of service on the same set
differently colored tape or ink on labels
Lacing cable
lace conductors on run of feeder cable, keeps cables lying flat and straight, prevents rolling, identifies different runs
Why not cover cable with plywood or lauan
does not provide ventilation, known to start fires
o-zone
area outside the protected rails fo the catwalks in the perms. need fall protection
pin-splitter tool
bends apart smooshed pins, bad, bent contacts in bates can cause flicker problems
waterfall
vertical run of cable going into the perms, or coming back down.
4/0, socapex, 60 or 100A dimmer lines
rig a spare
loop knot
provides a closed loop, used to tie a line to a light to hoist it
hitches
knots used to tie off a rope to a fixed object, or to tie a rope around an item so the rop confroms to the item to whih it is tied
may constrict or bind so as to make a tight hold on an item when under tension, such as a vertically hanging cable
bend
a knot tht ties one line to another line, such as when passing the two loose ends of the tie-line around the post and tying them together
dressing a knot
making sure that the knot is formed correctly and that the lines pass out of the knot in the correct way
setting a knot
tightening the working elements of the knot, often y pulling on the working end of the rope, so that the knot cannot be shaken loose
..
Three types of loop knots
Bowline, Bowline on a night, alphine butterfly
Four types of binding hitches
Clove hitch, Prusik, Rolling Hitch, Constrictor knot
Three other hitches
High Safety knot, highwayman’s hitch/draw hitch, trucker’s hitch
Bowline
commonly used to tie rope to the requipment for hoisting or hanging
strong and secure if tied correctly
Clove hitch
commonly used to tie a line to cable, to suspend a cable drop, or as a tieline for the cable.
weight of the cable makes the knot rip the cable.
not as reliable as other binding knots
must be oriented so taht the rop passed around the far side of the cable first, not oriented such that the lines converge into the knot before they pass around the cable
Square knot
very commonly used, not considered a very strong bend.
right over left, left over right
Three bends
square knot, alpine butterfly bend, flemish bend or figure eight bend
What determines strength of rope- (4)
type of knot you tie, age and condition of the rope, type of rope, thickness of the rope
tensile strength
breaking point of rope when brand new under a static load, no knots
WLL
work load limit- load limit can be routinely put on the rope in straight tension, allows a margin of dafety and longevity of the line
typically 10-25% of tensile strength
Static load
Just hangs, no load is purely static
Dynamic loading
Rope tugs, stops or starts in raising and lowering, swings.
Can require a rope 10× as strong as static load
Knots decrease strength of rope
Rate rope to 50% of nominal strength (will)
WLL of 1/4 in manila rope
54 lbs
WLL manila rope 3/8 in
122 lbs
1/2 in WLL manila rope
264 lbs
WLL manila rope 5/8 in
496 lbs
WLL manila rope 3/4 in
695 lbs
Hemp/jute
Manila rope
Knots well (not slippery)
Will not melt
Degrades ober time with heat, use chain, aircraft cable safeties
Nylon, polyester, Dacron, pro-manila pros
Better tensile strength
Better able to withstand shock, heat sunlight
“Pipe”
1 1/2 in IPS 1.9in OD schedule 40 steel pipe
Check list for hanging lights above set
Leave two loops of slack at each head for pan, tilt, moving
Sash cable neatly at regular intervals
Label each light visible from below, label powercord the same number
Lights power switch on
Tighten nuts on c-clamp
Safety cable loops through the bail and over pipe to prevent light falling. Barn doors and chimeras also safeties ( aircraft for smaller, nylon webbing or chain for larger lights)
Don’t wear tool belt
Rigging light with trapeze
Raised the old fashioned way with block and tackle
Lights tied off with guide lines, secured with chain
Single whip block and tackle
Mechanical advantage = 1
Single whip block and tackle with block at weight
Mechanical advantage = 2
Gun tackle purchase
Mechanical advantage = 2
Luff/Watch tackle
Mechanical advantage = 3
“wringing out”
Checking distribution system for short circuits, continuity, correct voltage, and line loss
