BMET Course 103 Electrical

Alternate Power

one or more generator sets or battery systems where permitted, intended to provide power during the interruption of the primary electrical service.

American Wire Gauge (AWG)

a standard system for designating wire diameter

Current Carrying Capacity (ampacity)

maximum current an insulated conductor can safely carry without exceeding its insulation and jacket temperature limitations

Disconnecting Means

device of group of devices by which conductors of a circuit can be disconnected for source of power

Emergency Power Supply (EPS)

source of electricity capable of providing power to an Emergency Power Supply System (EPSS)

Emergency Power Supply System (EPSS)

an EPS coupled to a system of conductors, disconnecting means, protective devices, transfer switches, control, supervisory, support devices and load terminals of transfer equipment needed to operate as a safe and reliable source of power

Fault Current

Hazardous, unintended and uncontrolled flow of current in an electric circuit due to a fault condition

Gauge

physical size of a wire

Ground

earth

Grounded

connected to ground

Grounding System

system of conductors that provides a low-impedance return path for leakage and fault currents

Isolated Electrical Distribution Systems (Isolated Power System)

a system compromising of an isolating transformer, a line isolation monitor and ungrounded circuit conductors

“Let-Go” Current

current level where the electricity causes muscles to contract until the current is removed

Primary (normal) Power

power usually produced by a public utility to provide normal operating power to a facility

Category 1

Due to power loss, failure of equipment or system is likely to cause major injury or death of patients, staff, visitors

Ex: Critical Care Units, Special Care Units, Operating Rooms

Category 2

Due to power loss, failure of equipment or systems is likely to cause minor injury of patients, staff or visitors

Ex: General Care Areas, Impatient bedrooms, Dialysis Units

Category 3

Due to power loss, failure of equipment or system is not likely to cause injury, but may cause discomfort to patients, staff or visitors

Ex: Examination Rooms, Treatment Rooms, Dental Rooms

Category 4

Due to power loss, failure of equipment or system is not likely to have a physical impact on patient care

Ex: Sterile Supply, Laboratories, Morgues

Meter

Measures amount of energy used by facility

Service Panels (Breaker Box)

Fuses, Circuit Breakers, Surge Protectors

Non-Essential Loads

1. Isolated or non-Isolated power

   1. General lighting

   2. General Lab equipment

   3. Non-critical service equipment

2. Outlets

   1. Standard outlets hospital grade outlets

   2. Ground-Fault Circuit Interrupters (GFCI)

Transfer Switches

Used to transfer between normal power source and emergency power source

Emergency Electrical Distribution System

1. Isolated or non-isolated power

2. Essential Loads

   1. Patient Care Space Categories

      1. Category 1

         1. Ex: Operating room, emergency room

      2. Category 2

         1. Ex: Critical Care lighting (Exit signs), Elevators, Automatic Doors

Branch Circuits

circuit conductors between the final overcurrent device protecting thee circuit and the outlets

Life Safety Branch

responsible for supplying power to lighting, receptacles and equipment essential for life safety that is automatically connected to the emergency power system during the interruption or primary power (essential loads)

Critical Branch

responsible for providing power for task illuminations, fixed equipment, select receptacles, select circuits serving patient care areas that is automatically connected to the emergency power system during the interruption of the primary power

Equipment Branch

circuits arranged for delayed, automatic or manual switching to the emergency power system during the interruption of primary power (non-essential loads)

Ground-Fault-Circuit-Interrupter (GFCI)

shuts off power in 1/40th of a second

de-energizes circuit when ground current exceeds 6mA

Surge Protector (type 1)

provides protection to external power surges and lightning strikes

Surge Protector (type 2)

Protects facility from internal power surges

Surge Protector (type 3)

used to protect sensitive equipment

Wire Sizing Factors

1. Load of circuit

2. length of circuit

3. Circuit breaker size

Gauge to Amps

AWG

1. 14 AWG - 18 amps (15 amp breaker)

2. 12 AWG - 24 amps (24 amp breaker)

3. 10 AWG - 33 amps (30 amp breaker)

Kcmil

1. 250 kcmil - 245 amps

2. 600 kcmil - 413 amps

3. 1000 kcmil - 542 amps

kcmil ranges

starts at 250 kcmil and increases to 2000 kcmil

AWG Ranges

#40 Smallest

#4/0 Largest

*Smaller the gauge number, larger the wire, larger current allowed

*Larger the gauge number, smaller the wire, smaller current allowed

Grounded (neutral) Conducotr

1. white wire

2. Normal current carrying wire

3. Needed for equipment to operate

Grounding Conductor

1. Green Wire

2. Not used as the normal current carrying wire

NFPA 70

Reference used to determine wire sizing for different applications in specific situations

Line Isolation Monitor (LIM)

Continuously monitors the maximum current that could flow between an isolated power conductor and isolated ground

Green Light Signal

System is adequately isolated from ground

Red Signal Light (Audible Alarm)

Current reaches 5mA under normal conditions

Ungrounded Circuit Conductors

Conductors within an isolated power supply that are not connected to the primary grounding circuit

Testing of EPSS

12 times a year (once a month)

Minimum of 30 minutes

Will be tested under a load