103A Intro to Electrical, Safety Connections & Meters Flashcards
Safe electrical measurement techniques
- Wear electrical hazard protecting gloves, shoes, and eye protection
- Use only one hand to move meter leads from point to point
- Remove power sources while you use ohmeters
Circuits as low as _____ can cause death
46 VAC
Current flow as little as _____ can kill you
0.25A
Heart failure; possible death
100-200mA
1A(ampere) =
1000mA (milliamps)
Factors affect current on the human body
- Area of contact
- Pressure of contact
- Skin resistance
- Point of contact
Resistance is measured in
Ohms
To prevent the electrical hazards of shock and electrocution
- De-energize
- Lock out
- Tag out
AFTER you de-energize a circuit, what’s the 3 step voltage test
- Test the meter to a known voltage
- Test the equipment circuit to verify that it is de-energized
- Verify the meter to a known power source again
Safety glove colour code
- Beige - Class 00 - Up to 500 volts
- Red - Class 0 - Up to 1000 volts
Class 00 & 0 are sufficient for RACM
If an electrical shock occurs
- Remove the victim
- Prevent further injury
- Send for qualified help
- Eliminate the danger
- Report the incident
How many keys can open the lock?
One key only
Lockout procedure
- Notification
- Shutdown
- System Shutdown
- Lock out
- Tag
- Recheck
- Re-energize
CAT 3 & 4 are to be the safest instruments for RACM to use
T or F
True
1 & 2 are not sufficient, 4 is sometimes overkill
Testing equipment without the CSA marking, no matter what its condition, may be unsafe to use
T or F
True
Never use an ohmmeter on an energized circuit
T or F
True
_____ generate high-voltage, low-current signals for testing the breakdown strength of electrical insulation resistance(IR)
Megohmmeters
One standard for machinery safety states that, for test voltages at 500 VDC, the minimum insulation resistance is 1MO
T or F
True
If the amperage reading is lower than your meter’s capability, you can loop the single conductor through the clamp more than once
T or F
True
Amperage = Meter Reading/Number of Loops in Wire
You use megohmmeters to test the __________ of electrical insulators
Insulating qualities
A megohmmeter produces a _____ voltage output
High
Both a true RMS meter and an averaging meter will provide the same reading when you use them with RACM electrical circuits
T or F
False
You are using a digital voltmeter to measure voltage. What does it mean if the numbers it displays are flashing on & off?
The range overload setting on the meter is bigger than the measurement
What does it mean if a digital meter displays a negative number?
The meter connects in reverse polarity to the DC circuit
