Nvent Erico srf n series User manual

nVent.com/ERICO

SRF N-Series Surge

Reduction Filters

Installation and Operating Instructions

nVent.com/ERICO

Table of Contents

1 INTRODUCTION ........................................................................................................................................................................ 3

2 WARNING.................................................................................................................................................................................. 3

3 INSTALLATION CAUTIONS........................................................................................................................................................ 4

4 IDENTIFY THE DISTRIBUTION SYSTEM .................................................................................................................................... 5

5 MOUNTING THE SRF................................................................................................................................................................. 8

6 OPTIMISING PERFORMANCE ................................................................................................................................................... 9

7 SERVICING AND TROUBLESHOOTING .................................................................................................................................... 16

8 BACKPLANE MODELS............................................................................................................................................................. 18

9 SCHEMATIC DIAGRAMS ......................................................................................................................................................... 18

10 PHYSICAL DIMENSIONS ....................................................................................................................................................... 19

nVent.com/ERICO

Installation and Operating Instructions

nVent ERICO Surge Reduction Filters (SRFs)from nVent

incorporate high energy clamping devices and special filtering

circuitry. SRFs are installed in series with the circuit, usually at

the point of entry to the building or structure. They are available

in single or three-phase configurations for load currents from

63A to 800A per phase.

The purpose of an SRF is to filter and protect against lightning

induced transients. The SRF provides a clean, filtered supply of

electricity to all output connected equipment when installed in

accordance with the manufacturers ' instructions.

Protection is achieved via a three stage circuit. This includes

the internal nVent ERICO Spark Gap unit as the primary surge

diverter, a purpose designed low pass filter network and a

secondary Transient Discriminating (TD)diversion stage to

further clamp the transient energy to safe levels. This allows

the SRF to:

• Provide filtering to the clamped waveform in order to reduce

the rate of voltage rise.

• Provide a secondary stage of surge diversion to protect

equipment from transients which may be induced onto the

SRF output cables or be caused by the load itself.

The use of this combination of technologies provides the

benefits of high surge capability, low let through voltage

and considerably reduced dv/dt. This applies to both surge

performance and over-voltage withstand from short and long

duration high-energy surges.

1 INTRODUCTION

HAZARDOUS VOLTAGES EXIST WITHIN THE SRF ENCLOSURE.

THIS UNIT SHOULD BE INSTALLED & SERVICED ONLY

BY QUALIFIED PERSONNEL AND IN ACCORDANCE WITH

RELEVANT NATIONAL ELECTRICAL & SAFETY CODES. ALL

INSTRUCTIONS MUST BE FOLLOWED TO ENSURE CORRECT

AND SAFE OPERATION OF THE SRF.

• Over-current and short-circuit protection must be provided to

protect the SRF and associated wiring if a fault develops. The

over-current protection should be installed in such a manner as

to provide a means of isolating the SRF from the main supply.

This unit contains overvoltage protection components and

may be damaged by installation resistance testing.

• SRFs contain capacitors. Disconnect power at least

1 minute prior to opening door. Check voltage prior to

working on SRF internals.

• SRFs must be connected to a low impedance earth ()

for correct operation.

• SRFs must be installed in accordance with ALL relevant

national electrical and safety codes.

• The power supply to the SRF should always be turned off

(and locked)before the door is opened for any purpose.

• Check all SRF terminals for tight connections.

(Some terminals may become loose during transport).

• Ensure all input and output cabling, once installed is

tightened to the correct torque settings (see table 2).

• Do not disconnect upstream Earth or Neutral connections

supplying the SRF while power is still applied, as this may

damage the SRF or load.

• No combustible items should be stored within the SRF

during operation.

• Do not leave this manual inside the SRF after applying power

to the SRF. Retain this manual for future reference.

• Failure to heed instructions or warnings may result

in personnel injury, equipment damage or ineffective

transient protection.

2 WARNING

nVent.com/ERICO

Installation and Operating Instructions

• Transient protection devices are usually rated to protect

against non-repetitive pulses from sources such as direct or

induced lightning energy.

• They are not designed to provide protection against repeated

cyclic anomalies such as those caused by motor speed

control notching (variable speed controls, etc).

• SRFs are not designed to provide protection against

sustained over-voltage conditions where the supply voltage

exceeds, for an extended period of time, the nominal rating of

the protection equipment. i.e continuous over-voltages from

poorly regulated generators or distribution systems.

• Smaller power generation equipment does not always

conform to the same standards of voltage regulation that

is in place for mains power reticulation. A large number of

smaller or cheaper generators have a voltage waveform that

approximates 240Vrms (often poorly regulated), but more

importantly, which often contains significant higher order

harmonics and may exhibit a peak voltage on each half cycle

far in excess of the normal 340V (peak). Such machines

are usually capacitive excitation induction generators, as

opposed to synchronous generators. The problem is usually

increased when the generator is lightly loaded.

• Harmonic voltages may also be present in distribution

systems that do not feature generators. This is normally

where non-linear loads are used, such as UPSs, rectifiers,

switch-mode power supplies and motor speed controls. The

harmonic voltages may have peak voltages in excess of the

protective clamping voltages, causing problems such as

excessive heat build up. Because the harmonic waveforms

contain higher order frequencies, capacitive leakage currents

may increase to above prescribed limits and shorten the

life of the SRF. It should be noted that in sites with large

harmonic voltage distortion, the SRF capacitance may

dramatically affect the power factor.

• Seek the manufacturers ' advice before installing any SRF

into a circuit which features a total harmonic voltage ratio

above 5%.

• With large transients, significant energy may be passed by

the SRF diverters back to the source or to earth. This may,

under some circumstances, cause upstream earth leakage

circuit breakers or residual current devices (ELCBs & RCDs)

to nuisance trip. Where possible, these devices should be

installed after the SRF in order to reduce this possibility.

• Transient protection devices often have minimum

requirements for upstream fusing to ensure proper operation.

See section 6.1 for fusing requirements.

• By-pass switches are not recommended to be used with

SRFs as they compromise the protection offered. The

connection of the by-pass switch compromises the input to

output separation requirement by bringing the SRF input

and output wiring into close proximity at the switch.

3 INSTALLATION CAUTIONS

Figure 1. Seek specialist advice with the above installations.

SRF

SRF SRF

ELCB

RCD

NON PREFERRED NON PREFERRED PREFERRED

AVOID UPSTREAM EARTH LEAKAGE CIRCUIT BREAKERS

(ELCB’S) OR RESIDUAL CURRENT DEVICES (RCD’S)

BYPASS SWITCHES

BYPASS SWITCHES COMPROMISE PROTECTION

AVOID REPETITIVE VOLTAGES IN EXCESS OF SRF RATING AVOID HIGH HARMONIC VOLTAGES

276 Vrms

240 Vrms

GENERATOR

GENERATOR GENERATOR

SRF SRF

MAINS / GENERATOR CHANGE OVER SWITCH CONNECTION

nVent.com/ERICO

Installation and Operating Instructions

A number of different power distribution systems are employed

in various countries around the world. It is important to

identify the distribution system in use prior to installation of

the SRF, and confirm that the SRF is the model recommended

by the manufacturer for that distribution system. To identify

the distribution system in use, consult reputable and

knowledgeable sources such as:

• The local power supply authority

• Local electrical engineers

• Applicable regulatory bodies or standards associations

Alternatively, confirm the type of distribution system used by

personal inspection. By visually tracing the neutral and earthing

conductors from the load equipment or sub-distribution

point back to the point of entry (and perhaps to the supply

transformer), the type of distribution system should be

identifiable with the aid of the following diagrams (figures 2-6).

These are prescribed in local regulations and describe the

relationship between the source, exposed or conductive parts

of the installation and earth. Amongst these, the TN-C, TN-S,

TN-C-S and TT systems are most commonly encountered.

Note that supplies such as those used in industry and mining

may often use a different distribution system to that of the local

supply authority.

4 IDENTIFY THE DISTRIBUTION SYSTEM

Regulations differ between countries. Check compliance with appropiate authorities

Figure 2. TN-C system: In this system, the neutral and protective earth conductor combine in a single conductor

throughout. All exposed conductive parts are connected to the PEN conductor.

nVent.com/ERICO

Installation and Operating Instructions

Figure 3. TN-S system: In this system, a separate neutral and protective earth conductor are run

throughout. The protective PE conductor can be the metalic sheath of the power distribution cable or separate conduc-

tor. All exposed conductive parts of the installation are conducted to this PE conductor.

Figure 4. TN-C-S system: In this system, a separate neutral and protective earth functions combine in a single PEN

conductor. This system is also known as a Multiple Earthed (MEN) system and the protective conductor is referred to as

the combined neutral earth (CNE) conductor The supply PEN conductor is earthed at a number of points throughout the

network and generally as close to the consumer 's point of entry as possible. All exposed conductive parts are connected to

the CNE conductor.

4 IDENTIFY THE DISTRIBUTION SYSTEM

nVent.com/ERICO

Installation and Operating Instructions

nVent ERICO Critec SRFs provide protection for equipment on

TN-C, TN-S, TN-C-S and TT single and three phase systems when

selected, installed and earthed in the specified manner.

The diagrams are provided as a guide to identifying and

distinguishing the distribution system in use. Metering,

over-current protection, and other details have not been shown.

The SRFs are designed to be used in distribution systems that

provide a separate earth and neutral connection. SRFs should

not be used in IT distribution systems. (Refer Figure 7)

As electrical wiring and safety regulations differ from country

to country, it is important to ensure that the installation

complies with all regulations applicable to the location.

Please seek further assistance if uncertain.

Regulations differ between countries. Check compliance with appropiate authorities.

Figure 5. TT system: A system having one point of the source of energy earthed and the exposed conductive parts of the installa-

tion connected to independent earthed electrodes.

Figure 6. IT system: A system having no direct connection between live parts and earth, but having all exposed conductive parts of

the installation connected to independent earthed electrodes. nVent ERICO Critec Surge Reduction Filters should NOT be used in IT

systems without specialist advice.

4 IDENTIFY THE DISTRIBUTION SYSTEM

nVent.com/ERICO

Installation and Operating Instructions

5 MOUNTING THE SRF

Before mounting the SRF, refer to Table 3 (weights and

dimensions on last page of this manual)which provides

dimensions and unit weights. Ensure that appropriate lifting

equipment is used when installing the larger SRFs. When

installing the SRF, consideration should be given to future

service needs. Ensure that clear view of the status indicators

is provided. The SRFs should be mounted away from other

electrical apparatus (300mm minimum)and in a position that

avoids close proximity to combustible materials.

The SRFs are designed to be wall mounted. Mounting brackets

(as shown in Figure 7)are supplied. The internal backplane may

be removed to facilitate wall mounting. Carefully disconnect the

wiring going to the front door LED before removing backplane.

The cabling and upstream over-current protection requirements

and all instructions provided in this manual, should be taken into

consideration before mounting the SRF.

To preserve the IP rating, SRF units from 63A to 250 A must

be installed in accordance with figure 9 and section 6.2.

• Larger SRF units from 500A to 800A are ventilated and

should be mounted in a dust and moisture-free, ventilated

environment.

• All SRFs should be installed in a dry, well-ventilated area.

Avoid sites subject to moisture ingress.

• SRFs are not intended for use in harsh or corrosive

environments.

Where the SRF is to be enclosed in a switch board cubicle,

models are available without the enclosure. These backplane

units are denoted by the model number suffix 'BP '.

SUITABLE WALL

ANCHORING

SEE TABLE 3 FOR

MOUNTING DIMENSIONS

WASHER

INTERNAL NUTS

BRACKET

BRACKET. INSTALLER TO PROVIDE

SUITABLE ANCHOR BOLT

Figure 7a. Typical mounting arrangement for wall mounted nVent ERICO Critec Surge Reduction Filters (63A to 250A).

Figure 7b: Typical mounting arrangement (500A to 800A).

nVent.com/ERICO

Installation and Operating Instructions

6 OPTIMISING PERFORMANCE

6.1 FUSING

6.2 CABLING

The protection equipment must be earthed and installed in

accordance with all relevant national electrical and safety

standards. The term "point of entry " protection, is a general

descriptive concept of zonal boundary protection, as detailed

in standards such as IEC 62305. Some local wiring regulations

may allow the protection equipment to be mounted directly

at the point of entry, while other countries require protection

equipment to be installed after the metering or main circuit

isolators or over-current protection.

The following installation points require attention to ensure that

optimal protection is provided by the protection equipment. This

information is provided as a guide only. Compliance with local

electrical and safety regulations must be ensured.

Over-current and short-circuit protection must be provided

in order to protect the SRF and associated wiring if a fault

develops. The over-current protection should be installed in such

a manner as to provide a means of isolating the SRF from the

mains supply. This is an important safety consideration.

The SRF N-Series SRFs do not incorporate overcurrent

protection. Upstream fusing or circuit breakers MUST be

installed. The amperage of this upstream overcurrent protection

must not exceed the load current rating of the SRF. For example,

the SRF25ON filter should be installed with upstream protection

rated at less than or equal to 250A. The load current rating of

the filter is noted on the Ratings Label on the inside of the SRF

enclosure door (and duplicated on the external side surface of

the enclosure).

The cabling and earth wires connected to the filter input should

always be run separately, with a minimum clearance of 300mm

between them and all other cables or sensitive equipment

(as shown in Figure 8 ). The input cable and earth wire will carry

the transient energy, while the protected output cable can be

considered to be a "clean filtered " supply.

By separating these cables, any incoming transients will not be

induced from the input cables onto nearby clean cables. This

clearance will reduce the possibility of arc-over from input to

output cables. Where cables need to run closer together due

to space restrictions, input and output cables should cross at

right angles and not be installed parallel to each other. Cabling

should be sized in accordance with all relevant wiring standards

to ensure that the full load current can be safely supplied. All

cabling or busbars connected to the protection equipment

should be securely anchored to prevent undue stress being

applied to input/output terminals.

Input and output terminal requirements are detailed in Table 2.

The input and output earth connections connect together on

the backplane earthing stud. This earthing stud provides the

function of connecting these earths together for continuity, and

also the functional electrical earthing of the SRF, together with

the safety earthing of the SRF enclosure. The 250A to 800A

SRFs have cable tie holes in the backplane to allow the incoming

and outgoing earth cables to be secured to the backplane

(see Figure 9).

• Cable glands (of an appropriate design)must be used for all

input and output cables to preserve the IP rating of the 63A to

250A SRFs.

• To protect input and output cabling insulation from sharp

edges around the cable entry holes suitable cable glands or

grommets must be installed.

nVent.com/ERICO

Filter rating Phase and Neutral Terminals Earth Terminal

Termination Method Size Torque Termination Method Size Torque

63A Screw Terminal Block 10 to 35 mm28.5 N.m Backplane Stud 1 x M8 8.5 N.m

125A Screw Terminal Block 25 to 120 mm219 N.m Backplane Stud 1 x M8 8.5 N.m

250A Screw Terminal Block 25 to 120 mm219 N.m Backplane Stud 1 x M8 8.5 N.m

500A Stud Terminal Block 1 x M10 30 N.m Backplane Stud 1 x M10 17 N.m

800A Stud Terminal Block 2 x M10 30 N.m Backplane Stud 1 x M10 17 N.m

SINGLE PHASE (63A - 125A)

SRF

300 mm

300 mm 300 mm

INPUT

LINE

OUTPUT

LOAD

“Clean”

protected

wiring

Keep cables

and equipment

away from this area

Safe area

Hazardous area

Figure 8. Maintaining clearance between input and other cabling.

Table 2. Termination details for SRFs

6.2 CABLING

Installation and Operating Instructions

nVent.com/ERICO

SRF163N

SRF3500N

2X CABLE TIE

HOLES ON

BACK PLANE TO

FASTEN EARTH

CABLE IN POSITION

OUTPUT INPUT

6.2 CABLING

Figure 9. Typical earth cabling

Installation and Operating Instructions

nVent.com/ERICO

6.3 OUTPUT DISTRIBUTION

As the output of the SRF is considered to be a "clean filtered

" supply it should not be subjected to situations where further

transients can be introduced. The "clean " supply should

not be run external to the facility, ie to provide power to an

external building or tower lighting. From the aspect of transient

protection to do so would create possible points of entry for

transient energy to the protected zone.

A similar scenario exists where the output of the SRF is fed

to an electrically "noisy " load. Any transients developed by this

load may also be fed to other equipment connected to the

same supply.

Electrically noisy equipment should ideally be supplied from

a separate SRF and all cabling should be run in isolation

to other cables.

SRF

RIGHT

SRF

ALTERNATIVE CONNECTION

AIRCRAFT

WARNING LIGHT

AIRCRAFT

WARNING LIGHT

AIRCRAFT

WARNING LIGHT

PREFERRED CONNECTION

REVERSE CONNECTED SRF

INCORRECT CONNECTION

WRONG

SRF

SRF SRF

RIGHT

SRF

Figure 10. Isolation of sensitive equipment from noisy sources.

Installation and Operating Instructions

nVent.com/ERICO

6.4 EARTHING

The earths for all site equipment should be integrated

(preferably deploying a single point earthing approach)and an

equipotential earth plane should be created. Integral to this is

the elimination of earth loops. It is common, but incorrect from

the point of lightning protection for there to be separate earths

for various services, ie electricity mains, telephone. computer

equipment and other building services.

For sites where the interconnection of these earths is

difficult, either for practical or regulatory reasons, the use

of a Potential Equalisation Clamp (PEC)is recommended.

The PEC behaves as an open circuit under normal operation,

but under surge conditions it activates to effectively clamp

individual points together.

The effectiveness of an SRF is intimately related to the

impedance presented by the earthing system to which it is

connected. A low impedance route to the earth is required (less

). This can be achieved by ensuring that the earth

electrode system at the site presents a low surge impedance

with respect to the ground. Additionally, the interconnecting

cabling must be of adequate cross sectional area and be routed

to provide as short and direct a path as is practical.

The earth conductor for the SRF should be sized according

to local regulations but with a minimum size of 6mm2, Every

attempt should be made to limit the cable length to under 5

metres. By selecting the most direct route, with the minimum

possible number of bends to the earth point or internal earth

bar, the risk of side flashing and excessive voltage rise across

the equipment is reduced. Figure 14 depicts the correct earthing

concept as described above.

ALL POWER AND

DATA CABLES

ENTER OR LEAVE

THE BUILDING

ON THE

SAME SIDE

(TO AVOID

EARTH LOOPS)

Figure 11. Preferred approach to equipotential bonding.

Installation and Operating Instructions

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6.5 CONNECTION OF ALARM CIRCUITS

6.6 INSTALLATION ARRANGEMENT FOR AUSTRALIAN MEN SYSTEMS

The SRF secondary surge diverters are continuously monitored

and their internal protection status is identified by the green LED

on each phase blue secondary Unit (SRFSUAC for phase 1, and

SRFSU on phases 2 and 3 if present).

Reduction in surge handling capacity activates a set of voltage

free alarm contacts which can be used to shut down the load or

to activate an external warning.

When mains voltage is applied to the SRF and the surge

diverters are fully functional, the alarm contacts will be in the

energized or normal state. The NC contact will be in short circuit

with the COM contact. Should the surge handling capacity

fall to below the alarm threshold, these contacts will be in the

de-energised or alarm state and the NO contact will be in short

circuit with the COM contact.

The contacts are "Fail-Safe ' in that, if power to the unit fails, the

contacts will revert to the de-energised or alarm state.

The alarm contacts should only be connected by an

appropriately qualified person owing to the possibility of mains

voltage being present in the SRF cabinet. Care should be taken

to route the alarm wiring away from the input circuit and any

other current-carrying conductors.

Alarm contact ratings:

• 5A @250VAC

• 54 @ 30 VDC

• 4kV Isolation

See section 7 "Servicing and Trouble Shooting " for further

information.

Under Australian Standards classification, SRFs are considered

a piece of equipment to be connected to the mains supply. They

are not intended for use as switchboards, distribution boards or

other equipment. As these devices are classified as "electrical

equipment AS 3000 Wiring Regulations apply to the installation

and operation of the units.

AS 3000 specifies minimum requirements for electrical

equipment that is connected to switch boards or distribution

boards. For a point of entry application in the multiple earth

neutral (MEN)distribution system, the SRF equipment should

be installed as close as possible after the MEN point and after

both the main disconnect switch/over-current protector and any

metering equipment. The SRF therefore, may not be installed at

the physical "point of entry " of the mains power to the building.

It must be earthed and installed in accordance with all other

applicable electrical and safety standards. As the protection

equipment is hardwired, the installation must be inspected by

an appropriately authorized electrical authority official prior

to commissioning.

Figure 12. Typical connection detail for SRF point of entry installation in MEN system.

Installation and Operating Instructions

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6.7 SRFS ON SUB-CIRCUITS

Where SRFs are installed to protect equipment on a particular

sub-circuit, it is strongly recommended that additional

protection be installed at the power point of entry. Primary shunt

protection at the point of entry should be used to divert the peak

surge currents away from the sub-circuit. This will reduce the

risk of cross-coupling of transients onto adjacent circuits and

will reduce the risk of flashover between the locally grounded

chassis and the earth circuit.

Figure 13 details the role of point of entry protection in these

instances. The cables supplying the input to the SRF and the

connection to the earthing system will carry a proportion of the

surge energy which has been let through the primary

point-of-entry protector.

Care should be taken therefore, in the routing of these cables to

ensure that this energy will not couple onto adjacent circuits.

In some instances it will be necessary to provide a separate

earth electrode for the SRF (subject to compliance with

relevant wiring regulations), particularly where the filter is to be

installed on a sub-circuit some distance from the existing earth

electrode. In this instance, the new electrode should be located

as near as possible to the SRF. This secondary electrode must

be electrically bonded to the existing earthing system via the

most direct route possible, using flat copper tape, and should

be buried to an appropriate depth.

This earthing arrangement is depicted in Figure 13. If a

secondary earth cannot be installed, or the earth impedance



special care must be taken. The risk of flashover between the

locally grounded chassis and the earth circuit may exist.

Careful attention must be paid to equipotential bonding of

the protected equipment.

Figure14. Earthing of an SRF remote from MEN point. Subject to compliance with relevant national stan-

dards). Care is needed ro avoid earth loops within protected environment.

Figure13. Operation of primary shunt protection and SRFs on sub-circuit

Installation and Operating Instructions

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7 SERVICING AND TROUBLESHOOTING

HAZARDOUS VOLTAGES EXIST WITHIN THE SRF ENCLOSURE.

THE SRF SHOULD ONLY BE SERVICED BY QUALIFIED

PERSONNEL, IN ACCORDANCE WITH RELEVANT NATIONAL

ELECTRICAL & SAFETY CODES.

Do not disconnect upstream earth or neutral connections

supplying the SRF while power is applied to the unit, as this

may damage the SRF or load.

Only replace the primary spark gaps or secondary TDS surge

diverters with an identical type.

Voltage-free alarm contacts are activated should the secondary

protection status fall below a pre-determined level.

The SRFs are essentially maintenance free, although periodic

inspection is recommended to ensure that the ventilation

louvres (where fitted)do not become clogged with dust.

INITIAL POWER CHECK

All indicators, alarms and surge counters (where fitted)should

be checked on a regular basis.

Should any of the display indicators fail to illuminate, check for

the following conditions:

• Is power available to the SRF?

• Check the input voltage by measuring the voltage between

active and neutral

• Has the upstream circuit breaker or fuse tripped?

INDICATORS

If power is being supplied to the SRF and the indicators still

fail to all correctly illuminate, then it is possible that either the

primary Spark Gap or secondary TDS devices have exhausted

their surge capacity. In such circumstances, the particular

devices should be replaced as a matter of urgency as they are

no longer providing optimum protection.

PRIMARY SPARK GAPS

With power correctly supplied, the Phase Spark Gaps should have

their green LEDs illuminated. Note that in the 250A to 800A SRFs,

these Spark Gaps are supplied via Spark Gap Fuses. If power is

correctly applied, and a Phase Spark Gap does not have its LED

illuminated, check the adjacent fuse. If the fuse has operated

(blown)it needs to be replaced. If the fuse is still in good order, the

Spark Gap needs to be replaced. Blown fuses may be temporarily

replaced with a 125A 22mm x 58mm gG Fuse. Note that this fuse

will not allow the full rated surge current to be diverted by the

associated Spark Gap. The correct replacement fuse should be

obtained from nVent as soon as possible.

Note that the N-E Spark Gap does not have an LED.

SECONDARY UNITS

The Secondary Units are blue in colour and contain the

secondary shunt diverter module and the filter capacitance

(see Figure yy). They are fed from individual 20A fuses. The

Phase 1 Secondary Unit is fitted with the Alarm Contacts, and it

is marked as SRFSUAC. On three phase units, the Phase 2 and

Phase 3 Secondary Units are marked as SRFSU. The status of

each SRFSUAC and SRFSU unit is indicated by the green LED

included on each. A correctly powered and operating SRF will

have all Secondary Unit LEDs illuminated green.

A Secondary Unit LED that is not illuminated indicates one of

the following:

• A blown Secondary Unit Fuse (replace Fuse)

• A failed Diverter Module (replace Module)

• An SRFSU or SRFSUAC internal failure (replace SRFSU or

SRFSUAC unit)

Troubleshooting proceeds in the order indicated here:

1)Check fuses for continuity, and replace blown fuses with 20A

10mm x 38mm gG fuses.

2)Check Diverter Module indicator flags. These should appear

as the textured window, with a faint grey/red tinge. Any window

showing a bright red colour should be replaced. Modules may

be gripped with the fingers and pulled straight out, away from

the Secondary Unit. Replace with an identical module obtained

from nVent.

3)Where all fuses and modules have been checked as OK,

then the affected Secondary Unit itself needs replacing

(ie the SRFSUAC or SRFSU unit).

Phase 1

SRFSUAC

LED Status

Phase 2

SRFSU LED

status

Phase 3

SRFSU LED

Status

Diagnosis

Green Green Green All OK

Extinguished Green Green Replace Phase 1

SRFSUAC unit

Extinguished Extinguished Green Replace Phase 2*

SRFSU unit

Extinguished Green Extinguished Replace Phase 3*

SRFSU unit

*It is possible that both the Phase 1 SRFSU and Phase 2

(or 3)SRFSU units are faulty in this circumstance, but the

above diagnosis is more likely.

Obtain the correct model Secondary Unit (SRFSUAC or SRFSU)

from nVent and wire in to replace the faulty unit. Exercise care

when replacing the wiring to ensure the resulting wiring is

correct. It may be useful to take a photograph before removing

the faulty unit.

FRONT DOOR LED INDICATOR

This indicator will be illuminated green if all Secondary Units

are indicating correctly.

Installation and Operating Instructions

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7 SERVICING AND TROUBLESHOOTING

N-E SPARK GAP

PHASE

SPARK

GAPS

PHASE 2

SRFSU

UNIT

PHASE 3

SRFSU

UNIT

SPARK GAP FUSES (250A TO 800A MODELS)

PHASE 1 SRFSUAC UNIT

SRF3500N

SECONDARY UNIT FUSES

N-E SPARK GAP

PHASE 1 SPARK GAP

SECONDARY UNIT FUSE

SRF163N

GREEN

STATUS

INDICATING

LED

DIVERTER

MODULE

STATUS

INDICATING

FLAG

ALARM CONTACTS

(ON SRFSUAC ONLY )

FIGURE YY- SECONDARY UNITS ( SRFSUAC AND SRFSU)

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Installation and Operating Instructions

nVent.com/ERICO

8 BACKPLANE MODELS

9 SCHEMATIC DIAGRAMS

This document details the installation procedure for our current

range of standard SRFs.

Backplane units are also available, and are denoted by 'BP ' as

a suffix to the model number. These units are supplied without

the proprietary enclosure and are intended to be mounted in a

customer 's provided switchboard.

SINGLE-PHASE SRF MODELS

FUSE

SECONDARY UNIT

PRIMARY

DIVERTER

SECONDARY

DIVERTER

INPUT/LINE OUTPUT/LOAD

E E

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Installation and Operating Instructions

nVent.com/ERICO

10 PHYSICAL DIMENSIONS

Note – Enclosures typically come with a gland plate on the

bottom, but not on the top. Simply punch the entry and exit holes

at the location that best suits the installation circumstances.

The single phase models will generally be punched completely

within the bottom gland plate, while the three phase models will

have the inputs punched on the top surface and the outputs on

the bottom surface. See Section 6.2 Cabling.

SRF Model Enclosure Size (mm)Mounting (mm)

W H D X1 X2 Y1 Y2 Fastener

Diameter

Weight

(Kg)

SRF163N 400 300 200 360 470 260 370 10 10.3

SRF125N 400 300 200 360 470 260 370 10 12.3

5RF363N 400 500 200 360 470 460 570 10 17.7

SRF3125N 400 500 200 360 470 460 570 10 21.6

SRF325ON 600 800 200 560 670 760 870 10 41.7

SRF3500N 800 1000 300 760 876 960 1076 10 76.6

SRF3800N 800 1200 300 760 876 1160 1276 10 97.2

Table 3. Physical Dimensions and Weights

Installation and Operating Instructions

Power Protection TVSS Device

Communications Line Protection Device

Ground Electrode

Power

Distribution Panel

Telephone Main

Distribution Frame

PCS,

Radio &

Telemetry

Equipment

Power Ground

AC Transformer

Sub Station

Overhead

Distribution

Voltage

Transmission

Lines

Telephone Lines

Direct Lightning Strike

nVent ERICO SYSTEM 3000

Active Lightning

Protection System

1Capture the

lightning

strike

3Dissipate Energy

into the Grounding

System

Low Impedance Ground

using at copper radials and

Ground Enhancement Material

Inspection Well

2Safely Convey

Energy to

Ground

5Protect Incoming

AC Power

Feeders

File

Server

PABX

Inverter

Rectier

Batteries

Ground

Potential

Equalization Bonding

TVSS

Remote

Data

Terminal

Sub-Distribution

Board

Bond All Ground

Points Together

Printer

Billing

Computer

Signal Control

Lines

Induced Surge

Because lightning protection, grounding,

equipotential bonding and surge

protection are all interdependent

technologies, reliable protection of

structures and operations demands an

integrated system approach.

nVent ERICO SYSTEM 3000

Active Lightning Protection System

nVent ERICO SYSTEM 2000

Conventional Lightning

Protection System

6Protect Low Voltage

Data/Telecommunications

Circuits

Capture

the Lightning

Strike

Protect

Low Voltage Data

Telecommunications

Circuits

Safely

Convey Energy

to Ground

Protect Incoming

AC Power Feeders

Bond All Ground

Points Together

Dissipate Energy

into the Grounding

System

Our powerful portfolio of brands:

CADDY ERICO HOFFMAN RAYCHEM SCHROFF TRACER

WARNING: nVent products shall be installed and used only as indicated in nVent 's product instruction sheets and training materials. Instruction sheets are available at nVent.com/ERICO and from your nVent customer service representative.

Improper installation, misuse, misapplication or other failure to completely follow nVent 's instructions and warnings may cause product malfunction, property damage, serious bodily injury and/or death, and void your warranty.

© nVent. All nVent marks and logos are owned or licensed by nVent Services GmbH or its affiliates. All other trademarks are the property of their respective owners.

nVent reserves the right to change specifications without notice.