staying alivewhen the power lines come down: post-storm safety and electric utility familiarization

Warren RogersSafety Supervisor, Eastern ConnecticutConnecticut Light & Powerwarren.rogers@nu.com

Staying AliveWhen the Power Lines Come Down

Post-Storm Safety and Electric Utility Familiarization

Michelle LowtherPrincipal

Continuity Housingmichelle@continuityhousing.com

Electrical System Awareness - Surviving the

Aftermath and the Beforemath

Warren Rogers - CL&P Safety

What Is Electricity?

Voltage

Current

Resistance

The flow of electrons from one atom to anotherin a complete circuit

Strength of the electrical pressure

Electric flow in a conductor

Resistance to the flow of current (in Ohms)

GREAT ELECTRICAL CONDUCTORS

Substation

Riser

Transmission

Distribution

Underground 23 Kv

Riser

Cutouts/Fuses

Primary

Insulators

Cross Arm

Recloser

Primary Voltage Conductors – 3 phase

Secondary Voltage Triplex

Shy bird

Bare copper primary

Primary

Secondary

Phone/cable

Transformers

Fuses

DANGEROSHA/NU’s Rule for

NON QUALIFIED PERSONS

MINIMUM - 10’ FOOTCLEARANCE FROM

ANY OVERHEAD LINES

Triplex Secondary Conductors

Primary

Secondary

Triplex120/120neutral

FREE SERVICE

Improperly installed generators have the potential to back feed downed wires

Step Potential - The potential gradient developed across the surface of the earth as a result of current flowing through the earth

Touch Potential - The potential measuredfrom an object that may be touched andthe earth one would be standing on

Broken Primary

Touch potential

Step Potential

Step Potential

Could the guard rail be energized ?

Phase of 23kv after three shots of Recloser

Phase landed here

Was there any step and/or touch potential?

Car vs Pole - Primary knocked off pole onto street, then car hit hydrant flooding street. 2 Good Samaritans died running to help car when they steppedinto water with down Primary. Seven others seriously injured attempting to rescue the 2 GS’s.

Effects of Electrical ShockCurrent (amperage) is the killing factor in electrical shock.

EFFECTS OF AC CURRENT ON AVERAGE HUMAN1 Milliampere (mA) Slight Tingling - Threshold of perception(1/1000 amp)5 mA Sensation of shock - can let go

Accepted as maximum harmless current (GFCI TRIPPED)

6-30 mA Painful Shock - Still have muscular control

50-150 mA Painful Shock - Loss of muscular control200 – 500 mA *1,000 – 4,300 mA* Ventricular Fibrillation - Heart leaves its * OSHA beating pattern and goes into a vibrating

mode before shutting off10,000 mA Cardiac Arrest, Severe Burns & probable Death * OSHA

15,000 mA Typical home circuit breaker (Breaker in panel tripped)

Ground Fault Circuit Interrupters - GFCI – Saves lives !

Why Men Invented GFCI’s

Fatality - exit wound after aluminum ladder contact w/secondary service

Stay Alive – Stay in Vehicle,Call 911Tell by-standers to stay back Stay in vehicle until utility company tells you the area is safe

Never trust any wire, primaryOr Secondary, to be safe until the utility rep says it is !!

Michelle LowtherPrincipal

Continuity Housingmichelle@continuityhousing.com

(832) 594-8286

Housing for critical personnel when you need it most.