What are two requirements for trailing cable disconnects?
Marked and identified
Designed so it can be determined to be disconnected by viual inspection
100
What are three requirements for temporary splices in trailing cables?
1. Made in a workmanlike manner
2. Mechanically strong
3. Well insulated
100
How long may temporary splices be used?
24 hours
100
Within how many feet of a machine not having a cable reel may a temporary splice be made?
25 feet
100
Within how many feet of a machine having a cable reel may a temporary splice be made?
No limitation
200
The term "splice "means the mechanical joingin of how many conductors that have been severed?
One or more
200
What are four requirements for permanent splices in trailing cables?
1. Mechanically strong
2. Adequate electrical conductivity
3. Adequiate flexibility
4. Effectively insulated and sealed to exclude moisture.
Also vulcanized or otherwise treated with suitable materials to provide flame resistant qualities and good bonding to the outer jacket.
200
Trailing cables shall be clamped to machines in a manner to protect the cable from what and to prevent what?
To protect from damage and to prevent strain on the electrical connections
200
Trailing cables shall be adequately protected to prevent damage by what type of equipment?
Mobile equipment
200
Trailing cable and power cable connections to junction boxes shall not be made or broken under what condition?
Under a load
300
How must metallic sheaths, armors, and conduits enclosing power be grounded?
Approved methods
300
Metallic sheaths, armors, and conduits enclosing power conductors shall be maintained in what condition?
Electrically continuous throughout
300
Metallic sheaths, armors, and conduits in resistance grounded systems where the enclosed conductors are a part of the system will be approved if a solid connection is made to what conductor?
Neutral
300
How shall metalic frames, casings, and other enclosures receiving power from single phase 110-220 volt circuits be grounded?
By a separate grounding conductor connected to the grounded center tap on the transformer.
300
What are the two approved methods of grounding metallic frames, casings, and other enclosures receiving power from direct current power systems with one polarity grounded?
What is Diode grounding and third wire
400
Equiment grouding wires must be how large where the power conductor is No. 6 A.W.G. or larger and how large if the power conductor is smalller than a No. 6. A.W.G.?
1/2 the cross sectional area
Equal to the size of the power conductor
400
What type of DC equipment may not be frame grounded by the use of silcon diodes?
Equipment receiving power from DC systems with neither polarity grounded
400
Where such diodes are used on circuits having a nominal volatage rating of 250, they must have what minimum ratings?
Forward current rating of 400 amperes or more and peak inverse voltage rating of 400 or more.
400
Where such diodes are used on circuits having a nominal voltage rating of 550, they must have what minimum ratings?
Forward current rating of 250 amperes or more and a peak inverse volatage rating of 800 or more
400
Where circuit breakers are used at the outby end of a trailing cable connected to electrical equipment employing silicon diodes, the instantaneous trip setting shall not exceed what percent of the nominal current rating of the grounding diode?
300%
500
Overcurrent devices must be used and installed in such a manner that the operating coil circuit of the main contactor will open when a fault current with what value of the diode rating flows through the diode?
25% or less
500
The silicon diode installed must be suitable to the grounded polarity of the power system used and its threaded base must be solidly connected to what?
The machine frame on which it is installed
500
In addition to the grounding diode, a polarizing diode must be installed in the machine control circuit to prevent operation of the machine when what condition exists?
When the polarity of the trailing cable is reversed
500
How shall frames of stationary high voltage equipment receiving power from undergrounded delta systems be grounded?
Approved methods
500
No work shall be performed on any high voltage line on the surface which is supported by any pole or structure which also supports other high voltage lines until all the lines are what?