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(Frequently Asked Questions)

Below is a list of the most common questions from Hager customers.
Still can’t find an answer to your question? Please contact us.
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What is cascading and how do I use it?
This principle is defined in the Wiring Rules Clause and allows a lower fault rated device to be installed downstream and still comply with the fault rating requirements for equipment installed at a particular point. We use this in the design of switchboards to keep size to minimum, costs down and maintain the integrity of fault ratings.
What is discrimination and how do I use it?
This principle is used by supply authorities to ensure continuity of supply. Where, under fault conditions a downstream device such as an MCB in a switchboard operates, but does not affect the upstream service protective device. We consider this when designing switchboards.
Can I fit accessories?
Yes, a full range of accessories fit the h3 MCCB range. These include auxiliary, signal, shunt trip and under voltage trip, similar to MCB. Each range has specific handles and barriers etc. The accessories can be retrofitted, when the front cover is removed (MCCB trips), no copper/metal parts are exposed.
Each range (x160, x250, h250, h630, h1000 and h1600) has a separate selection of accessories and auxiliaries.
Can I adjust the current ratings / trip settings?
With the exception of the x160(Thermal only) all of the H3 MCCBs have incremental thermal / short circuit trip adjustments or a selectable thermal / short characteristic. Please refer to the relevant MCCB user instructions.
What does LSI mean?
This refers to electronic trip units. Long time delay, Short time delay and Instantaneous time delay. This assists with discrimination and fault loop impedance compliance in switchboard design.

Load Break and Isolator Switches

What's the difference between Load Break and Isolator Switches?
Load break switches are intended to close on full load current and open on full load current. The switch contacts open/close rapidly in a wiping motion that cleans contacts.
Isolator switches are intended to operate on no load.
Do I need to consider fault ratings during the design of an installation?
Yes, the load break needs to be able to withstand the forces generated by a fault until a protective device operates. So the peak withstand rating of the switch should be less than or equal to the peak let through level of the largest protection device in series with the switch.
When should I use a load break switch versus isolator?
  • A Load break switch is used when isolation is required under load.
  • An isolator switch is typically used in a domestic application or when loads can be turned off before the isolator is operated.
What does AC22, AC23 mean?
  • AC22 - switching of mixed resistive and inductive loads including moderate overloads.
  • AC23 - switching of motor loads or other highly inductive loads.


What does C-Curve mean?
There are 3 curve characteristics for magnetic operation,
  • B - 3-5 times line current used on generators and long runs, not widely available in Australia.
  • C - 5-10 times, light and power circuits, most common, widely available.
  • D - 10-20 times, highly inductive load, motors, transformers, some discharge lighting, welders.
What accessories can be fitted?
Hager's MCB Accessories include auxiliary contacts (on/off condition), signal contacts (MCB tripped due to fault), shunt trip (remote operation off), undervoltage (35-70% of nominal causes MCB to trip), locking device, and heat dissipation inserts.
What affect does high ambient temperature have on the operation?
Hager MCBs have thermal/magnetic characteristics that are affected by ambient temperature.
Refer to the MCB Technical Information when installing Hager MCBs in ambient temperatures other than 30°C.
What does the kA rating of a circuit breaker imply?
All Hager circuit breakers have been subjected to short circuit testing at their marked rating and are capable of successfully interrupting the fault current without undue damage to the circuit breaker. The circuit breaker should not be installed into an area where the prospective fault level is higher than the rating of the circuit breaker (except where cascading is used as a design feature under Clause of the Wiring Rules). Commercial installations and installations close to distribution transformers will have relatively higher fault levels. Consult your energy distributor for the fault level at a given installation.
Should I twist the end of a stranded cable before terminating into a Hager MCB?
No. By not twisting the cable, the strands are able to spread out and fill the terminal as it is tightened. This maximises the contact area of the cable to the terminal resulting in a cooler running joint and a stronger connection. Always physically check the strength of a connection after tightening.


What is a Type A RCCB/RCBO?
Type A RCCB/RCBOs are sensitive to both AC and pulsating DC sine waves. Recommended for welding machine protection where a DC offset may be used by the machine operator (a DC offset may saturate the differential relay of a standard Type AC device and it may not trip when required). Type AC RCCB/RCBOs are sensitive to AC sine waves only.
Can I connect a Hager Residual Current Device (RCD) to a DC supply?
No. Hager RCCBs and RCBOs are not suitable for DC applications.
RCD Nuisance tripping or Unwanted tripping ?
It is very tempting to describe RCD tripping due to intermittent electrical fault as ‘Nuisance Tripping’. However, ‘Nuisance Tripping’ probably best describes an RCD that trips for no electrically based reason whatsoever.

Intermittent tripping that typically occurs after a new installation, maintenance or wiring modification would suggest that the RCD is performing the very function for which it was designed / installed for (i.e. fault detection & protection). This intermittent or ‘Unwanted Tripping’ can actually highlight potential problems within the installation, turning the simple exercise of fitting of an RCD, into a huge fault finding exercise. This is not a relished thought for any sparky!

Typically ‘Unwanted Tripping’ on RCDs can stem from misplaced or combined Neutrals. At times, Neutrals intended for protection by the RCD are incorrectly wired to the ‘pre-RCD’ Neutral bar. Other times, current is accidentally shared between the ‘pre-RCD’ Neutral bar and ‘post-RCD' Neutral bar (e.g. via a common bond that should not exist in the first place). Another important consideration is the effect of Standing Leakage Current & how it relates to ‘Unwanted Tripping’ (Refer to FAQ – Standing Leakage Current…..).

Standing Leakage Current & how it relates to Unwanted Tripping on RCDs.

Standing Leakage Current is inherently present in all electrical appliances due to the RFI filters and suppressors inside switch mode power supplies on modern appliances such as LCD TVs, Hi-fi systems, PCs and Laptops. This also occurs in leaky cable appliances with pre-existing poor insulation resistance, or an insulation breakdown developed over time.

Typically ‘Unwanted Tripping’ is blamed on the RCD being overly sensitive. More often than not, it is the Standing Leakage Current that is the problem. The steady state sum of Standing Leakage Current in the circuit must be significantly less than the RCD tripping threshold. If this is very close to the RCD tripping threshold, then even the slightest transient disturbance will cause the RCD to trip.

Generally, RCDs may trip at any value in excess of 50% of the rated residual current (e.g. 15mA on 30mA RCD). Further care should be taken on installations that are susceptible to high transient disturbances or where particularly leaky appliances may be connected. The recommended Standing Leakage Current steady state threshold is less than 33% of the rated residual current (i.e. 10mA on 30mA RCD).

A list of appliance types and corresponding Standing Leakage Currents per unit are listed below:
Appliance typeStanding Leakage Current up to (mA) / unit
Handheld tools and portable appliances
0.75 mA / unit
Other household appliances
0.75 mA / unit
Information Technology (Portable)
0.75 mA / unit
Lighting Appliances
Information Technology (Stationary)
Electric Stove / Oven
Up to 0.75 / kW

As an example, for a 30mA RCD to stay under the threshold and avoid ‘Unwanted Tripping’, it is recommended that a maximum of four computers (desktops/towers) are connected to a single RCD circuit at any one time. The number of computers may need to be further reduced if they have particularly high Standing Leakage Current or where the installation is particularly susceptible to transient disturbances.

Surge Protection Devices

After a recent storm, customers rang to say their electrical products do not work anymore and they want surge protection. Can you help?
As individual situations can differ greatly from household to household and from area to area, please refer to the Surge Protection Technical Information or Contact us
Why is an MCB required before the surge protection device?
Surge Protection Devices do not generally have short circuit protection inbuilt and in some circumstances can continue to remain closed circuit after the metal oxide varistor (active component) has expired. This process is called thermal runaway, resulting in an active to earth short circuit. The MCB interrupts this flow, providing circuit protection.
What size earth conductors should be used?
The largest practical size conductor should be used for all connections where possible. The cables installed should be at least equal to or greater than the Main Earth Conductor used in the installation.
How do I protect computer and home theatre circuits?
Please refer to the Surge Protection Technical Information or Contact us


Why do I need to use a Contactor?
A contactor is an electromechanical device typically used with a control circuit to enable the switching of a high current load. Wired in an interposing arrangement, a contactor can safeguard delicate control devices (e.g. time clocks, timers, and sensors) against premature failures often caused by direct switching of the load (e.g. lights, fans, heater… etc ).

It is very important not to assume that the nominal AC1/AC7a current rating (eg 25A, 40A or 63A) is the contactor switching capacity for all types of load. For example, a 3P 25A contactor is not suitable for switching a typical 3ph 4kW motor (415V, 8.2A FLC) even though the 25A rating is higher than 8.2A. In this application, the suitable selection is a 3P 40A contactor.

The reason for selecting a 3P 40A contactor is simply because every load has a different ‘load characteristic’. It is this load characteristic that can detrimentally affect a contactors switching capacity. Hence, depending on the application or specific load type (heating, motor or lighting), the contactors nominal current is derated accordingly to ensure optimum operation and reliability.

Please refer to Contactor Technical Information when selecting a contactor.
What does AC1 (AC7a), AC3 (AC7b) mean?
AC1 (AC7a) and AC3 (AC7b) are utilisation categories or switching capabilities of load types.
  • AC1 (AC7a) – non inductive or slightly inductive loads, resistance furnaces.(power factor >0.8)
  • AC3 (AC7b) - inductive loads, squirrel cage motors: starting, switching off motors during running.

Time Delay Switches

I want a device to turn lights off 5 minutes after I turn the light switch off. How do I do this?
This function is called delay OFF, it is important to recognise the actual functional control you want. Select the device, EZ002 and adjust the timing dials to match your need.
Can I use a DC voltage to control a Time Delay Switch?
Yes. A DC control voltage (12 – 48V DC) can be used with all Delay Timers. The switched contacts are rated at 230V AC. See the user instructions for the connection of the various voltages (AC and DC).

Energy Meters

I have a 3 phase installation and want to monitor voltage and current. How do I do this?
Digital or analogue meters are available (discuss with your client their needs). You will also need selector switches for voltage and amperes. You will need CTs for the ammeter appropriate to the maximum demand of the installation.
Do I have to configure kWh meters?
Yes. The meter does not know the CT ratio you have connected. Failure to configure will result in incorrect readings. Please download the relevant kWh meter user instruction sheet for this procedure.
Are Hager CTs sensitive to the direction of current flow?
No. When the CTs are used in conjunction with Ammeters and Selector Switches, the polarity of their installation is not critical. When the CTs are used for Energy (kWh) Measurement, the relative polarity to CTs with regard to the Voltage connection.
How do I know how accurate the kWh reading will be?
Apart from the meters accuracy, the accuracy of the final installation depends upon the CTs used as well as the length and size of connecting cables.
Can I use Hager kWh meters to monitor usage on 2 tariffs at the same time?

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Are there options for doors on plastic Loadcentres?
The Golf, Vega D, IC2 and Mini-Gamma are available with choices of door type, opaque (white) or transparent (with blue shadow). Locks can also be fitted. The doors on the Vector weatherproof enclosures are available in both Transparent (clear) and Opaque and are also UV stable for the harsh Australian conditions.
Which enclosure can I use to fit into a corner, but still have access?
The mini gamma range has been specifically designed for this application.


I need to provide Safety Switch protected circuits from a Panelboard. What is the best method?
Several options to be considered:
1. The easiest method is to use Hager single module RCBOs. These are electronic devices Tpye A, 10kA, 6-32A.
2. Install a combination of a suitable 3 Phase MCb mounted to a Hager BD163T (Add-On Block) on the chassis.
3. Use earth leakage relays mounted on DIN rail, with the supply passing through the earth leakage toroid. The trip contacts of the earth leakage relay should be wired to the shunt trip of the supplying MCCB.
Do I need to consider the fault rating of the chassis?
Yes. The chassis has been tested at 20kA for 0.2 seconds, (40kA peak). A protective device needs to be installed prior to the chassis in order to interrupt supply to the chassis in the event of a fault. The peak let though current of the protection device must be less than 40kA to prevent damage.
Which way do Hager MCBs fit on the chassis?
Hager MCBs must be fitted with the DIN clip facing towards the centre of the chassis (the DIN clip can be removed if a hazard is considered to exist, eg live connection). This orientation places the exhaust port of the MCB away from the chassis. Also, the single module RCBO can only be mounted with the DIN clip facing toward the chassis. These chassis are not designed to suit other brands of MCB.


I have received a tender for a job requiring a maximum demand of 400A, what can you offer?
Hager's Quadro M Modular Switchboard System has been designed for this very application. Quadro M is a range of modular products with IP55 or internal IP20 frames that can be fitted with a range of mounting pans and chassis to suit the Hager range of devices up to 630A. This includes CT metering, whole current metering and check metering. We also offer a complete system design from the main board, panelboards, distribution boards, modular devices and wiring accessories. Please speak to your Hager Representative who can prepare a project quote for you. Contact us
Can you supply switchboards up to 1600A?
Yes. Hager's unimes 1600A Main Switchboards have been designed specifically for multi-residential and commercial applications, utilising patented profiles to guarantee optimum rigidity and total flexibility for a tailored design.
Contact us for more information.

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Wiring Accessories

Which switch do I need for switching fluorescent lighting loads?
Our standard light switch is rated for fluorescent lighting loads to the full rating of 16AX.
Will your socket outlets fit onto other brand mounting plates?
Yes. We have maintained the Australian industry standard of 84mm between mounting centres.
What is the difference between trailing and leading edge dimmers?
Trailing edge dimmers are designed for use with electronic transformers. Leading Edge dimmers are designed for use with iron core transformers.
What material are the plates and rockers made from?
Front plates and the external surface of rockers are all made from UV stabilised, Hi impact Polycarbonate. All mounting blocks are also made from the same material to allow for the best possible colour matching.
It is important to note that internal parts of the dual injection rocker and pivot points are made from chemically resistant ABS. This aids in prolonging the life of the switch from the use of domestic/commercial cleaning product.
What is the motor rating of your wall switches?
Our standard WBM16AX mechanism has a rating of M60.

tebis Building Automation

What does tebis mean?
Total Electrical Building Installation System. This system was developed by Hager. It was released in 1988 in Europe and 1999 in Australia.
What language or protocol does tebis use?
KNX is the protocol tebis uses. The protocol is based around a 29V DC control, EIB-Y cable and colour coded connections.
Can I programme tebis?
Tebis has been designed to be installed, programmed and modified by KNX trained electricians. To install and program tebis you must have KNX training accreditation.
What are the basic functions and commands of tebis?
Tebis is designed to control lighting, heating and small motor loads for domestic and light commercial applications. The functions available are switching ON and OFF, delay ON/OFF, dimming, group switching, priority switching, opening/closing blinds/shutters/projector screens, control temperatures in winter and scenario switching. Control is available via wiring accessories, push buttons, a weather station, time clocks, PE cells and more.

Time Switches

Can I switch a 16A load on timer contacts rated at 16A?
In theory yes, in practice NO. We do not advise this. We do not know what loads are being connected, therefore, it is safer to use a Contactor to switch the load and not the relatively expensive timing device.
I want to operate a school bell during school hours only, not on weekends or holidays.
A Hager EG293B or EG493E time clocks are the only devices that will comply with this application. We recommend programming these devices with the supporting EG003G USB interface and the EG003 software, a computer based program that enables easy programming of EGxxx series time clocks. The programme is entered into the computer and then downloaded onto the key supplied with the clock. This enables easy storage and modification of programmes.
I have installed an EG103E and now the time is one hour out due to daylight savings. Do I have to re-programme the Time Switch?
The EG103E a daylight savings as an automatic function which requires activation and the setting of dates for changes. Once set, the dates will be adjusted for each of the following years automatically. Refer to the user instructions for more information.
Note 1 - Select the 'USER' option, do not select 'AUS as the preset dates are incorrect.
Note 2 - The change to Daylight Savings time is the first date entered, then the change date for Eastern Standard time.
How can I secure a Time Switch Programme from tampering?
The EG103E and EG203E can be locked with the use of the EG004 Locking Key. The EG403E, EG293B and EG493E can be secured by programming in a PIN code. It would also be advisable to back up the original programme on a programming key.
Why isn't my EG071 Time Switch switching according to my programme?
The Time Switch may be in the override position. Press and hold the ON/OFF button for 3 seconds to revert to the auto mode.

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tehalit Cable Management System

What is the difference between ducting and trunking?
As defined by the Wiring Rules (Clause 1.4.39), a duct is a pipe of 75mm diameter or greater. Trunking (Cl 1.4.89) houses and protects electrical cables and conductors. These definitions have been in place for several editions of the Wiring Rules.
Is halogen-free product available for Government, Child Care Centres and Schools?
Yes, a range of slotted trunking in 2M lengths with cable retainers. These products do not emit toxic or noxious fumes when exposed to flame.