PERMISSIBLITY - PART IV

PERMISSIBLITY

100

How shall the grounding overcurrent device be connected in diode grounded systems?

In series with the grounding diode and with the operating contacts in the machine control circuit

200

How shall enclosure covers that provide accses to fuses other than headlight, control circuit and handheld fuses be designed?

Interlocked with a circuit-irrupting device

300

What is the ampacity of a number 10 AWG, 5-conuctor copper portable cord having a 600 volt 60 degrees celcius insulation rating when used in a 40 degree C ambient atmoshpere?

20 amperes

400

What is the maximum allowable lenght of a number 6 AWG portable cable when protected by a 300 ampere instantateous trip circuit breaker?

550 feet

PERMISSIBLITY

100

What is the purpose of a blocking diode grounded system?

Prevents operation of the machine with the polarity reversed.

200

Fuses shall be inserted on what side of the circuit interrupter?

Load side

300

What is the ampacity of a number 10 AWG, 7 conductor copper portable cord having a 600 volt, 60 degree C insulation rating when used in a 40 degree C ambient atmosphere?

14 amperes

400

According to Kentucky State Mining Laws, any equipment, device or explosive that has been approved by the United States Bureau of Mines, the Mining Enforcement and Safety Administration or the Mine Safety and Health Administration and that meets all requirements, restrictions, exceptions, limitations, and conditions attached to the classification by the approving agency is referred to as being?

Permissible

PERMISSIBLITY

100

Each motor shall be protected by what type of automatic device?

Overcurrent

200

What procedure shall an owner of approved equipment follow in order to make modifications of the equipment?

Apply in writing to Approval and Certification Division of MSHA

300

What is the ampacity of a number 1 AWG, 3 conductor copper portable power cable having a 5000 volt 75 degree celcius insulation rating when used in a 40 degree celcius ambient atmosphere?

130 amperes

PERMISSIBLITY

100

Three phase ac motors shall have an overcurrent device in at least two phases such that actuation of a device in one phase will cause the opening of how many phases?

All three

200

Proposed modifications of approved equipment shall not substantially alter what design feature that was originally approved for the equipment?

Basic function design

300

How many ohms per 1000 feet are present at 25 degrees Celcius in a number 10 AWG conductor?

1.04 ohms

PERMISSIBLITY

100

Circuit interrupting devices shall be so designed that they can be reset without what?

Opening the compartment in which they are enclosed

200

What is the ampacity of a number 1 AWG-3 conductor copper portable power cable having a 600 volt 60 degrees C insulation rating when used in a 40 degrees C ambient atmopsphere?

100 amperes

300

What is the maximum allowable circuit breaker instantaneous setting to provide short circuit protection for a number 4 AWG portable cable?

500 amperes