Cutler-Hammer Line Isolation Monitors for Hospitals

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CA08104001E For more information visit: www.cutler-hammer.eaton.com PIN 0951700

January 2003

Contents

Hospital Isolation Equipment36

Medical SystemsRef. No. 1313

H

o s p i t

a l I s o

l a t i o

n

E q u i p m e n

tDescription Page

Hospital Isolation Equipment

General Description of Product Family . . . . . . . . . . . . . . . . . . . . . . . . . . . 36.0-2

Advantages of Isolated Power Systems (IPS) . . . . . . . . . . . . . . . . . . . . . . 36.0-3

Isolated Power Panels (Type IPP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36.0-6

Isolated Power Centers (Type IPC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36.0-7

X-Ray and Laser Power Centers (Types XPC and LPC) . . . . . . . . . . . . . . . 36.0-8

Surgical Facility Centers (Type SFC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36.0-9

Line Isolation Monitors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36.0-10

Specifications

For complete product specifications in CSI format seeEaton’s Cutler-Hammer Product Specification Guide. . . . . . . . . . . . . Section 16473

Line Isolation Monitors

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6.0-2

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6

Medical Systems

General DescriptionRef. No. 1314

Medical Systems

DescriptionEaton’s Cutler-Hammer business, theleader in electrical distribution prod-ucts, has teamed with Isotrol Systems,a division of Bender, to offer a com-plete line of electrical products for usein the healthcare industry. All productsmeet or exceed UL, CSA and NFPAstandards. The entire product familyintegrates the use of isolated powersupplies, continuous monitoring forhazardous conditions, and testingof circuit conditions with maximumselectivity of tripping overcurrentdevices when hazards develop, andhighest patient and operator safety.

Isolated Power Systems are typicallyused in the emergency electrical distri-bution circuits associated with Life

Safety and Critical Care areas within ahealth care facility. See Figure 36.0-1 for details. For further details referencethe IEEE White Book — RecommendedPractice for Electrical Systems inHealth Care Facilities — ANSI/IEEEStandard 602.

A brief description of select IPS prod-ucts and their purpose follows.

Isolated Power Panels and Power Centers

Type IPP Isolated Power Panels aredesigned to provide isolated powerto electrical circuits installed inoperating rooms and other electricallysusceptible patient care areas. EachIPP includes a single- or 3-phasetransformer, a Line Isolation Monitor(LIM), a reference ground bus, aprimary circuit breaker, and a numberof branch circuit breakers all in a#14 gauge galvanized steel box with#14 gauge stainless steel (#304) coverwith a brushed finish. Single-phaseapplications are available from3 – 25 kVA, and 3-phase applicationsare available from 10 – 25 kVA. Formore IPP details see Page 36.0-6.

Figure 36.0-1.Health Care Facility —

Simplified Power Distribution ArrangementType IPC Isolated Power Centers areidentical to the IPP product with theaddition of an eight gang section forHospital Grade power receptacles andground jacks. For more IPC details seePage 36.0-7.

The LIM integral to each IPP or IPCdisplays the incremental changes inground leakage current as additionalmedical apparatus is plugged into thereceptacles and displays the totalsystem leakage current that will flowthrough a solidly grounded personwho comes in contact with an ener-

gized phase conductor either directlyor through an insulation failure.

X-Ray and Laser Isolated Power Centers

Types XPC and LPC X-Ray and LaserIsolated Power Centers are designedto provide isolated power to x-rayand laser receptacles within operatingrooms and other electrically suscepti-ble areas. Each XPC and LPC includesa single- or 3-phase transformer, a LineIsolation Monitor (LIM), a referenceground bus, a main breaker, branchbreakers, contactors, selector stationwith pushbuttons and LED indicatinglights, and a Programmable LogicController (PLC) all contained withina #14 gauge box and stainless steel(#304) cover. For more details on theXPC and LPC product, see Page 36.0-8.

Surgical Facility Centers

Type SFC Surgical Facility Centers aredesigned to provide isolated powerto electrical circuits installed withinoperating rooms and other electricallysusceptible patient care areas. Each

SFC includes a single-phase trans-former, a Line Isolation Monitor (LIM),a reference ground bus, a primarybreaker, up to 16 branch breakers,up to eight Hospital Grade powerreceptacles, up to eight Hospital Gradeground jacks, a two-section X-RayViewer, a clock and elapsed timer, andan AM/FM stereo system with cassetteand/or CD player. All equipment ismounted in a #12 gauge galvanizedsteel box with #12 gauge stainlesssteel (#304) brushed cover on the SFCproduct, see Page 36.0-9.

Line Isolation Monitors

Type LIM Line Isolation Monitors areavailable for single-phase or 3-phaseapplications, 50 or 60 Hz, 24, 100, 110,120, 200, 208, 220, 230, 240 and 277VAC system voltages. Two separateground connections are provided foradded safety when the LIM is wiredinto an Isolated Power System (IPP,IPC, XPC, LPC or SFC).

The LIM measures and displays thetotal hazard current (leakage current)for all medical equipment connectedto the branch circuit wiring on ananalog or digital panel meter. Avisual and audible alarm occurswhen the hazard current exceeds 2 or

5 milliamperes. The audible alarm maybe muted, however the visual alarmremains on for the duration of the hightotal hazard current.

A test switch can be activated to verifythat the LIM is operating properly. TheLIM has provisions for connecting oneor more remote stations installed closeto patient care areas. For more infor-mation on the LIM see Page 36.0-10.

G

Life SafetyBranch

DistributionPanelboard

CriticalBranch

EmergencySystem

IsolatedPowerPanel

CriticalCare Area

EmergencySystemReceptacles

•Color or marking•Panelboard + Circuit #•Hospital Grade (green dot)

F r o m N

o r m a l D i s t r i b u t i o n

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36January 2003

Hospital Isolation EquipmentMedical Systems

Application Information — IPSRef. No. 1315

Advantages of IsolatedPower Systems (IPS)Isolated Power Systems (IPS) werefirst introduced into the hospital envi-ronment as a means of reducing therisk of explosions in operating roomsand other areas containing or usingflammable anesthetizing agents. TheIPS functions by “floating” the second-ary power lines so that ground faults,the primary source of equipmentfailure, can be recognized at an earlystage, in a condition where they do notpresent first fault personal shock orincendiary hazards.

IPS systems offer additionaladvantages to system security andoperational safety for both operatorsand patients. The isolated powersystem is recognized as the safestpossible system and does provide

an additional layer of safety to bothpatient and operator alike.

Today, hospitals no longer useflammable anesthetizing agents, andthe use of isolated power is currentlyrecommended only for use in “wetlocations” where the loss of equip-ment power cannot be tolerated.

Reference to these facts may be foundin the Health Care Facilities Handbook(Second Edition), and on page 214,Chapter 6, of the IEEE RecommendedPractice for Electric Systems in HealthCare Facilities (The IEEE white book)ANSI/IEEE Standard 602-1986.

The following discussion explains theadvantages that IPS systems offer overconventional grounded systems and theGround Fault Circuit Interrupter (GFCI).

The Grounded System

Figure 36.0-2 shows a conventionalgrounded system. The neutral of thetransformer is bonded to ground.In Figure 36.0-3, we assume that aperson has a body resistance of 1000 ohms.

If the 1000-ohm body touches the lineL, a current of 120 mA could flow fromthe line conductor, through the 1000-

ohm person, and return to the systemvia the low impedance neutral-groundconnection. This 120 mA could provedangerous to such a 1000-ohm person.

Should the person have less ohmicresistance, due to excessive moistureor internal body connections, largerand more lethal currents could flowthrough his/her body should he/shecome into contact with line L.

Figure 36.0-2.Conventional Grounded Systemhas One Side of Power Line Connected toGround. If the 1000-ohm Person Touches theLine (L), he will have 120 mA of CurrentFlowing Through his/her Body

Figure 36.0-3.Isolated Power System with1000-ohm Person. Secondary Side has No

Resistive Path to Ground, so if System NetCapacitance is Low, Human Could ContactEither Side of Power Line Safely

Figure 36.0-4.Schematic Representation ofTypical Distributed Capacitance in an IPS

Figure 36.0-5.Equates to the Circuit Below

Figure 36.0-6.1000-ohm Person in Contactwith One Line Conductor and Ground

Table 36.0-1.Comparison of Voltage Acrossand Current Flowing Through a Person

The Isolated Power System (IPS)

Figure 36.0-3 shows an isolated powersystem. There is no intentional ohmicconnection between the supply(neutral) and ground. The 1000-ohmperson has greater protection frompotentially lethal shock hazardbecause of the absence of the lowimpedance ground-system returnpath. However, there is always a“capacitive” path to ground becauseof the inherent system net capacitance

between any line conductor andground. Figure 36.0-4 assumes atypical equally distributed, balancedcapacitive system with small leakagecurrent (50 microamps) flowing fromL1 via C1, through the ground, andreturning to L2 via C2. We can mea-sure the voltage drop across thesystem capacitance by using a highimpedance voltmeter. In a balancedsystem as shown, we can expect tomeasure 60 volts from each line toground. Leakage current may at thistime be measured by connecting anmA or microamp meter from eitherL1 or L2 to ground.

The 50µA assumed current means thateach capacitance has an impedance of 1.2 x 106 ohms (Z = V/I = 60/(50 x 10-6)= 1.2 x 106 ohms). (50µA is assumedbecause it represents a typical lightload system leakage to ground.) 50µAcurrent corresponds to a capacitanceof C = 2.2 x 10-9 F or .002µF (at 60 Hz).Now, should our 1000-ohm personcome into contact with either side of the line, the maximum current thatcould flow through him/her would beonly 100µA as seen in Figure 36.0-4.Our 1000-ohm person coming intocontact with L1 has shunted oneside of the high impedance paths toground, and therefore will approxi-mately double the leakage currentto 100 microamps, which is stillan extremely low level for all butsubcutaneous patient leakage paths.

120V

208V0V

L

1000ΩN

G

120V

120V

208V

C1

L1

1000Ω

G

60V

L2

50µA

C2

I

120VL1

60V50µA

L2

60V

1000Ω

120V

L1

2.21 nF

L2

C2

V2V1

C1

2.21 nF

I

1000Ω

120VL1 L2

C2C1

Scenario Grounded IPS

VoltageoverPerson

120V 0.1V (with 50 microampinitial leakage)

CurrentthruPerson

120 mA 100 microamp (with50 microamp initialleakage)

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6.0-4


January 2003


6

Medical Systems


Voltage across the person would be:

Voltage across C2 would be:

Current passing through our1000-ohm person would be:

Table 36.0-1 compares the effect of the grounded system vs. IPS with agrounded 1000-ohm person in contactwith a line conductor of each system.

The Line Isolation Monitor

The Line Isolation Monitor (LIM) is a

device which continually monitors theimpedance (resistance and capacitance)from all lines (single- and 3-phase) toground, and indicates the maximumcurrent that could flow to a patient,should the patient come into contactwith the line conductor (i.e., defectiveequipment).

Note:many variables affect what currentcould actually flow to the patient:

1. The value of 1000 ohms may varybetween less than 100 ohms to20,000 ohms, depending on thecondition of the patient (moisturecontent, muscle condition, dry

skin, etc.).

2. Parallel leakage return paths willalso bypass a portion of the leak-age current from the patient.

ICU and CCU areas, where the patientmay be connected to several pieces of equipment (all of which contain theirrespective leakages, both resistive andcapacitive) greatly add to the possibil-ity of hazardous leakage currents flow-ing. We must never neglect the factthat a leakage on a grounded systemwill return via the low impedanceneutral-ground connection. Themagnitude of this current is limitedonly by the impedance of the parallelpaths to ground — for example, our1000-ohm person.

The isolated system does not have anylow-impedance connection to ground.It has a high-impedance capacitive/ resistive return path. This provides thelayer of electrical safety that protectsboth operators and patients alike.

Continuity of SupplyProbably the strongest argument forthe use of isolated power is wherecontinuity of supply is paramount.

Article 517-20 (1996 NEC) WetLocations states:

“All receptacles and fixed equipmentwithin the area of the wet locationshall have ground-fault circuit-interrupter protection for personnel if interruption of power under fault con-ditions can be tolerated, or be servedby an isolated power system if suchinterruption cannot be tolerated.”

Let us examine the advantages of theIPS system to see how it compareswith the alternatives: the groundedsystem and the GFCI (ground-faultcircuit interrupter).

Figure 36.0-7 is a schematic representa-tion of both grounded and ungroundedpower systems.

Figure 36.0-7.Schematic Representation of

Both Grounded (A) and Ungrounded (B)Power Systems

In the grounded system we see thatfault F1 will cause a large short-circuitcurrent (Isc) to flow to ground andreturn to the supply by the equipoten-tial ground (G) and the neutral bond.The magnitude of this current will belimited only by the circuit and faultimpedance, and typically will be inthe thousands of amperes range.Obviously, fuse F will quickly blowor, in the case of a circuit breaker,quickly trip.

When we compare the same situationwith the ungrounded system: Fault F2 (same location as F1) will cause a very small current Ic to flow to ground andreturn to the source via the systemcapacitance.

The magnitude of Ic is limited bycircuit and fault impedance which,in this case, is the system capacitance

(assumed to be .002µF).Ic= 120V/(1.2 x 106Ω) = 100 microamps

During fault F2, the line isolationmonitor would quickly alarm the faultcondition so that remedial action maybe taken — but no fuses or circuitbreakers will trip. Supply continuityhas been maintained by using an IPS.

Isolated Power vs. GFCI

The ground-fault circuit interrupter(Figure 36.0-8) is a device that maybe installed with a grounded powersystem. It reacts by tripping a circuitbreaker should leakage current exceed

the GFCI rating.

Figure 36.0-8.Schematic of GFCI Application

The unit operates simply by comparingthe current flowing out to the loadagainst current returning from theload. If both currents are equal, theirresultant sum is zero; the circuitoperates correctly.

1000

1201000----------------------- x120 0.1V=

1.2x106

1201000----------------------x120 119.9V=

120V

1201000----------------------- 100microamps=

Source

A

Load

L

G

N

Isc

F1Fuse F

Source

B

Load

L2

F2

IcG

L1

Iin

Iout

Source

CB

GFCI

∆IG

N

L

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36January 2003



Should the two currents not equal zero— i.e., a portion of the current returnsto the source via another path, aresidual current will be detected bythe GFCI. Should this residual currentbe in excess of the GFCI trip rating(5 mA), the breaker will operate andcut off power to the circuit.

Important — the GFCI does notprovide continuous and advancedmonitoring of equipment and circuitcondition, nor does it alert impendingproblems. The unit will simply tripwithout warning, and may be proneto nuisance tripping during erraticsupply conditions.

Short-Circuit Currents

Extremely large short-circuit currentscan flow in grounded systems (non-IPS) during a line-to-line or a line-to-ground fault condition. We shall

now examine how the IPS can reducethese large and damaging short-circuitcurrents, which helps prevent a totalsystem outage that could affect a largearea of the hospital.

Figure 36.0-9 shows a one-line for botha grounded and an IPS distributionsystem.

Figure 36.0-9.Typical Distribution Arrangementfor IPS (left) and Grounded Systems (right)

Figure 36.0-10 represents the corre-sponding fault impedance diagram.

Figure 36.0-10.IPS (left) and GroundedSystem (right) Reduced to Fault PathComponents

Assume a short-circuit fault occurs ona piece of equipment connected viaa 10-foot (3 m) cable to the output 20ampere circuit breaker of each system,and compare the results.

Calculations assume the above condi-tions with 208/120V transformer with0.051 pu reactance and the infinite busat system input. Cable impedance isassumed for 2 conductor, #12 AWG.

Figure 36.0-10 shows the instanta-neous currents that flow, and helpspredict circuit breaker clearing.

Comparison of the two systems

show that the IPS system experiencesreduced magnitude of short-circuitcurrent by a factor of approximately4:1 on the secondary side of our twosystems, and 7:1 on the primary side.Obviously, fault energy dissipationdamage is proportionally reducedusing IPS.

In this example, only one circuit onthe IPS system, the faulty piece of equipment, would be disconnected.All other secondary circuits wouldbe unaffected by this fault condition.

When we compare tripping of breakerswith the grounded system, the 60

ampere breaker will trip and all second-ary 20 ampere circuits and connectedequipment could be affected by powerloss. Remember that in normal installa-tions, this main 60 ampere breakercould be feeding several circuits orseveral beds in an ICU or CCU.

The advantages of the IPS system inboth reduced energy dissipation atthe point of fault, and continuity of supply for the connected consumersare apparent.

Noise Reduction

Increased use of sensitive electronicsystems in the hospital environmenthas created a growing need to supplythese systems with “clean” voltage,free of noise and transients. Many datastorage and monitoring equipment aresensitive to line transients and linenoise frequently present on voltagefeeders. Noise has many sources —lightning strikes, switching surges,motors, SCRs, switched mode powersupplies, and discharge lighting, toname but a few. Many manufacturersof voltage-sensitive equipment haverecognized the problem created bytransients and noise on their equip-ment’s input line and have provideda measure of protection as an integralpart of their equipment. This protec-tion, however, may not be adequatefor frequent or serious disturbances.

The IPS system contains a qualityshielded isolation transformer whichprovides a convenient and effectivemeans of reducing or even eliminatingline-to-line and line-to-ground noiseon voltage feeders.

The IPS’s shielded isolation trans-former can provide a 50 – 70 dB atten-uation of wideband line-to-ground(common-mode) noise.

Note:dB = 20 log (V1 /V2).

As an example, a large 1500V transienthaving a frequency of about 750 kHz,will be reduced by a factor of 3162.3(70 dB) to a value of 0.47V by theshielded isolation transformer.

Although the primary reason for theIPS design and installation was notto achieve this attenuation, ratherto provide a low leakage secondarypower system, this is another “built-in” advantage when comparingisolated power with conventionally

grounded systems.

208V

60A

5 kVA

120V

20A

IPS System Grounded System

120V

60A

120V

20A

208V

60 A.C.B.

5.1%

120V20 A.C.B.

Z Cable

Fault

Isc607A

Isc350A

IPS System

120V

60 A.C.B.

20 A.C.B.

Z Cable

Fault

Grounded System

Isc2300A

Isc2300A

Z Cable

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6.0-6


January 2003


6

Medical Systems

Technical DataRef. No. 1318

Isolated Power Panels (Type IPP)

Figure 36.0-11.Outline Drawing for IPPs Single- and Three-Phase 10 to 25 kVA

Figure 36.0-12.Wiring Diagram for IPPs Three-Phase 10 to 25 kVA

Table 36.0-2.IPP Ratings

ᕃ Backbox size is reduced to 41-inch H x 24-inch W x 8-inch D (1041.4 mm H x 609.6 mm W x203.2 mm D) for 3, 5, 7-1/2 and 10 kVA transformers.

Transformer kVA Ratings ᕃ Voltages Volts AC Branch Breakers

Primary SecondarySingle-Phase Three-Phase Single-Phase Three-Phase

357-1/2

10152025

152025

120208220230240277380400480

120208220230240

14 Maximum2-Pole(Plug-in orBolt-on)

10 Maximum3-Pole(Plug-in orBolt-on)

1-inch (25.4 mm)

w

Plan

W

d

Front

A

A

H

ቪ

ቫ

ቧ

Circui t

Breakers

ቢ

ተ

ቯ

ቮ

ቱ

ቤ

h

ቩ

ብ

ባ

ViewA-A

1-inch (25.4 mm)

ቨ

To SystemGround

PanelGround

* Metered

RemoteOnly

To RemoteIndicatorSeriesMK2450(if required)

LZ Series LIM

*

IncomingPower

ቪ

1 2

3

5

7

9

4

6

8

10

L1 L2 L3

OR

ቨ

ቩ

ቫ

Note: The 3-phase isolation transformeris available in delta-delta andwye-delta configuration.

ተ

L1

12 Vac ComM-M+RI1

K1/NC

K1/ComK1/NOSafe

HazardRI2

L2

GND2LIM GNDTest/L3

ተ

ቮ

ቭ

*

Table 36.0-3.IPP Dimensions

ቢ S/S front trim.

ባ Backbox, galvanized steel.

ቤ Hat section, galvanized steel.

ብ Branch breaker subchassis.

ቦ Breaker deadfront.

ቧ Hinged door over circuit breakers.

ቨ LIM circuit breaker.

ቩ Loadcenter.

ቪ Primary circuit breakers, 1-, 2-,or 3-phase.

ቫ Branch circuit breakers, 1-, 2-,or 3-phase.

ቭ Isolation transformer:Phases 1-Ph 3-PhPower rating: kVAPrimary voltage: VSecondary voltage: VFrequency: Hz

ቮ Line isolation monitor, 1- or3-phase, analog or digital.

ቯ LIM connector plate.

ተ Reference ground bus.

ቱ Vent-holes for convection air flow.

Back-boxType

Dimensions in Inches (mm)

h w d H W

C 48(1219)

30(762)

14(356)

50(1270)

32(813)

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36January 2003



Isolated Power Centers (Type IPC)

Figure 36.0-13.Outline Drawing for IPCs Single- and Three-Phase 10 to 25 kVA

Figure 36.0-14.Wiring Diagram for IPCs Three-Phase 10 to 25 kVA

Table 36.0-4.IPC Ratings

Transformer kVA Ratings Voltages Volts AC Branch Breakers

Primary SecondarySingle-Phase Three-Phase Single-Phase

357-1/2

10

N/A 120208220230240277380400480

120208220230240

16 Maximum2-Pole(Plug-in Only)

w

W

Plan

A

A

H

Front

h

d

View A-A

ቪ

ቨ

ቧ

ቲ

ቤ

ቩ

ባ

1-inch (25.4 mm)

1-inch (25.4 mm)

IncomingPower

ቩቫ

ቪ

ቭ

ቨ

ቯ

ተ

ቮ

ቱ

H2

H1

X1

X2

OR

IZ Series LIM

To SystemGround

PanelGround

To RemoteIndicatorSeriesMK2450(if required)

* MeteredRemoteOnly

**

L1

L2

12 Vac Com

M-

M+

K1/NC

K1/Com

K1/N0

SafeHazard

R12

GND2

LIM GND

Test/L3

RI11 2

3 4

5 6

7 8

9 10

11 12

ቲ

Table 36.0-5.IPC Dimensions

ቢ S/S front trim.


ቤ Backplate, galvanized steel.



ቧHinged door over circuit breakers.


ቩ Loadcenter.

ቪ Primary circuit breakers, 1- or2-phase.

ቫ Branch circuit breaker, 2-phase.

ቭ Isolation transformer:Phases 1-PhPower rating: kVAPrimary voltage: VSecondary voltage: VFrequency: Hz

ቮ Line isolation monitor, 1-phase,analog or digital.


ተGround bus.

ቱHospital grade power receptacles.

ቲHospital grade ground jacks.

Back-boxType


h w d H W

B 41(1041)

24(610)

8(203)

43(1092)

26(660)

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6.0-8


January 2003


6

Medical Systems


X-Ray and Laser Power Centers (Types XPC and LPC)

Figure 36.0-15.Outline Drawing for XPC/LPC Single- and Three-Phase 10 to 25 kVA

Figure 36.0-16.Typical Circuit Arrangement for XPC/LPC

Table 36.0-6.XPC/LPC RatingsTransformer kVA Ratings Voltages Volts AC Branch Breakers

Primary SecondarySingle-Phase Three-Phase Single-Phase Three-Phase

10152025

10152025

120208220230240277380400480

120208220230240



Plan

w

W

H

A

A

d

h

ቱ

ታ

ቮ

ተ

ቯቦ

ቭ

ቩ

ብ

ቤ ባ

ቪ

ቫ

ቧ

Branch

Circuit

Breakers

ቲ ቢFront View A-A

C1 C2 C4

C5 C6 C7 C8

1-inch (25.4 mm)

ቨ

XFMR

PowerSection

ControlSection

NurseStation

Display

OutletDevice

In-UseLamp

DoorContact

Outlet

R e m o t e

I n d i c a t o r

LIM

O u t p u t

PLC I n p u t

Contactor

X-Ray and LaserIsolated Power Center

X-Ray and LaserReceptacle Module

Table 36.0-7.XPC/LPC Dimensions

ቢ S/S front trim.


ቤ Hat section, galvanized steel.





ቩ Loadcenter.

ቪ Primary circuit breakers, 1-, 2-,or 3-phase.

ቫ Branch circuit breakers, 2- or3-phase.

ቭ Isolation transformer:Phases 1-Ph 3-PhPower rating: kVAPrimary voltage: VSecondary voltage: VFrequency: Hz

ቮ Line isolation monitor, 1- or3-phase, analog or digital.



ቱ Vent-holes for convectionair flow.

ቲ Programmable logiccontroller (PLC).

ታ Secondary circuit contactor(C1…C8).

Back-boxType


h w d H W

C 48(1219)

30(762)

14(356)

50(1270)

32(813)

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36January 2003



Surgical Facility Centers (Type SFC)

Figure 36.0-17.Outline Drawing for SFCs Single-Phase 3 to 10 kVA

Figure 36.0-18.Wiring Diagram for SFCs Single-Phase 3 to 10 kVA

Table 36.0-8.SFC RatingsTransformer kVA Ratings Voltages Volts AC Branch Breakers

Primary SecondarySingle-Phase Three-Phase Single-Phase

357-1/2

15

N/A 120208220230240277380400480

120208220230240


00:0012:00

View B-B

Front

ABB

A

w

h

W

H

d

ቢ

ቮ

ት

ቴ

ቱ

ቲ

ቫ

ቧ

ታ

ቦ

ብ

ተ

ቭ

1-inch

(25.4 mm)

View B-B

IncomingPower

ቩቫ

ቪ

ቭ

ቨ

ቯ

ቱ

H2

H1

X1

X2

OR

IZ Series LIM

To SystemGround

PanelGround

To Remote

IndicatorSeriesMK2450(if required)

* MeteredRemoteOnly *

*

L1

L2

12 VAC Com

M-

M+

K1/NCK1/Com

K1/N0

Safe

Hazard

R12

GND2

LIM GND

Test/L3

RI1

1 2

3 4

5 6

7 8

9 10

11 12

ቮ

ቲ

13 14

15 16 To Clock, Elapsed Timer andControl Station

(For Wiring Details, seeData Sheet on ZT1491Clock/Elapsed Timer)

ተ

ACDC

Radio

To ExistingRoof Antenna

ቤ

ታቴ

X-RayViewer

ቶት

Table 36.0-9.SFC Dimensions

ቢ S/S front trim.


ቤ Power supply for stereo system.





ቩ Loadcenter.

ቪ Primary circuit breakers, 1- or2-phase.

ቫ Branch circuit breaker, 2-phase.

ቭ Isolation transformer:Phases 1-PhPower rating: kVAPrimary voltage: VSecondary voltage: VFrequency: Hz

ቮ Line isolation monitor, 1-phase,analog or digital.



ቱ Hospital grade power receptacles.

ቲ Hospital grade ground jacks.

ታ Stereo system.

ቴ Speakers.

ት Clock.

ቶ Elapsed timer.

Clock/elapsed timer remote control.

X-ray viewer.

Back-boxType


h w d H W

D 42(1067)

50(1270)

8(203)

44(1118)

52(1320)

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6.0-10


January 2003


6

Medical Systems


Line Isolation Monitors(Type LIM)

Digital IZ1492 1-Phase IZ1493 3-Phase

Analog IZ1490 1-Phase IZ1491 3-Phase

Figure 36.0-19.Line Isolation Monitors —Dimensions in Inches (mm)

LIM Features

s Less than 35 microampere LIMhazard current.

s No interference with medicalequipment.

s Hybrid design with special phase-

locking circuitry for ultimatestability and repeatability.

s Voltage-free SPDT contact forexternal usage.

s LIM overload protection withautomatic reset.

s Field adjustable 2 or 5 mAresponse value.

s Easy-to-clean ruggedLexan front.

s Analog display IZ1490 and IZ1491.

s Digital display IZ1492 and IZ1493.

Product Description

The Line Isolation Monitor (LIM)

detects the total leakage impedanceto ground in an AC isolated or un-grounded power system. Based onthis information, the maximum TotalHazard Current (THC) is determined.

The LIM is available for operation in50 or 60 Hz systems with the followingAC voltages: 24, 100, 110, 120, 200,208, 220, 230, 240 and 277V. The LIMrequires a separate supply voltageof 120V AC when used with a systemvoltage 24V. Otherwise, the supplyvoltage for the LIM is taken from thesystem to be monitored.

Two separate ground connectionsare provided for added safety whenwiring the LIM into an Isolated PowerSystem. Each ground should be wiredindividually to the Reference Ground-ing Bus. A break in either connectionwill cause the LIM to alarm.

Operational Information

The LIM function is to calculateand display the true maximum valueof the Total Hazard Current (THC).The LIM accomplishes this task usinga patented technique of measurement.

The THC is displayed either on an ana-log or digital panel meter. Normally,the green LED is “on” and the meteris in the non-alarm or safe green zone.THC levels will increase as additionalloads are connected to the systemand/or when a line-to-ground fault hassuddenly occurred or is slowly devel-oping. There is a visual and audiblealarm when the THC exceeds the LIMsetting of either 2 or 5 mA. Relay out-put contacts are also available whichcan be wired into a circuit to triggeran external alarm.

The visual alarm remains on for theduration of the fault. The buzzer can,however, be muted at the discretionof personnel in the vicinity of the LIM.The red LED that is built into the muteswitch comes “on” to indicate a mutedcondition.

A test switch can be activated to check-out the LIM operation. This actioncreates the equivalent of a fault andcauses the LIM to react as if a true faulthad occurred in the system. The meterthen goes into the red alarm zone, thegreen LED goes off, the red LED comeson and the buzzer sounds. The opera-tion of this switch does not add to therisk of electric shock within the systemin actual use, nor does it include theeffect of the line-to-ground strayimpedance of the system.

The LIM has provisions for connectingone or more remote stations with orwithout meter. Similar information

and test action is available at theseremotes as is provided by the LIM.

7

(177.8)

Recessed

Molex

Connector

View f rom Back

4

6)1.(1

4-1 / ( )108.

-.

6-1 / 8(155.6)

-7 / 1(1 )12.

2-1 / 263.5

1 / 8.2

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36.0January 2003



Table 36.0-10.Technical Data for LIM

Rated Insulation Voltage 300V

Insulation Class in Accordance with UL 1022Dielectric Voltage-Withstand Test

1500V

Rated Service Rating Continuous Operating

Rated Mains Voltage of VN

Frequency Range of VNOperating Range of VNMaximum Power Consumption

24/100/110/120/200/208/220/230/240V AC, Single-Phase

50 or 60 Hz (+/- 1%)85% – 110% of Rated Voltage7.5 VA

Measuring CurrentMonitor Hazard Current

Maximum 18 µAMaximum 35 µA

Minimum Internal Impedance at 50/60 Hz 4MΩ

Nominal Response ValueResponse ToleranceResponse RetardationResponse Hysteresis

5 mA Changeable to 2 mA1.8 to 2 mA or 4.6 to 5 mA< 5 sec.15% of Response Value

Output Contact Assemblies

Rated Contact VoltageMake CapacityBreak Capacity

at 250V DC and L/R = 0at 60V DC and L/R = 0at 24V DC and L/R = 0

Switching Life (220V AC/60 Hz)

One Voltage-Free SPDT Contact and one 12V AC,120 mA Remote Indicator Contact250V6A

0.4A0.7A6A2 x 106 Cycles

Operation Mode Continuous

LIM Overload Protection Built-in Thermal Overload with Automatic Reset

Ambient TemperatureWhen Operating

When Stored

10°C – 50°C50°F – 122°F-20°C – 50°C10°F – 122°F

Mounting Orientation Any

Connector 15-pin Molex, Type 03-09-2152

Weight Approximately 1.75 Lbs (.8 kg)

Physical Details

The LIM is less than 2-1/2 inches (63.5mm) deep. Cutout required for panelmounting is 4-5/16 x 6-3/16 (+0, -1/32)inches (109.6 x 157.2 mm). Mountingholes are on 4-inch (101.6 mm) and

6-1/2-inch (165.1 mm) centers.

A 15-pin female Molex connectoris built into the side of the LIM.A terminal board assembly with cableand 15-pin male Molex connector isavailable to facilitate field wiring.

A buzzer sound level adjustment,using a 1/8-inch (3.2 mm) Allen headwrench is conveniently accessiblethrough a hole in the top-side of the LIM.

The housing must be opened tochange the LIM response value toeither 2 or 5 mA.

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6.0-12


January 2003


6

Ref. No. 1324

CSA is a registered trademark of the Canadian Standards Association.UL is a federally registered trademarkof Underwriters Laboratories Inc.National Electrical Code and NEC areregistered trademarks of the NationalFire Protection Association, Quincy,Mass.

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Documents

Cutler-Hammer Line Isolation Monitors for Hospitals