Transformer Switch (50Hz) Building Shielding

This modular shield high purity Iron has very high magnetic permeability for 50Hz through to microwave frequencies.


High magnetic permeability causes the magnetic field to flow more easily in the shield than in free air. This is known as 'magnetic reluctance' or 'shunting the field'. Due to the reduction in available building land, high land prices and smaller building footprints, electrical switchgear, MV/LV transformer substations and plant rooms are increasingly being located near residential homes.

System 8000 - Global EMC

Choose This Test Chamber For

Iron+ ® has been specifically developed for VLF/ELF and broadband applications.

50Hz Shielding - Global EMC

50 Hertz

Shielding of high current cables, typically LV and HV mains feeder cables that are emitting high levels of EMF.

Magnetic Field Shielding - Global EMC

Magnetic Field

Optimised shielding for power frequencies (50/60 Hz) to prevent human exposure to potentially harmful levels of magnetic fields.

Building Shielding - Global EMC

Building Shielding

Suitable for industrial, commercial and large residential installations. Providing conformity to long-term public exposure limits of EMF.

Building Shielding

As the demand for electricity continues to rise, the installation of larger and more powerful transformers, along with their associated cabling, has become more prevalent. As a result of this, there has been an increase in the levels of power frequency electromagnetic interference (EMI) emitted from these equipment rooms and devices.

All high current sources in a building, such as transformers, bus bars, switchgear and power distribution cables, produce magnetic fields. These fields can pass through standard building construction materials and induce currents in the human body or electronic devices.

If intense enough, the radiated magnetic field can affect electronic equipment and the health and wellbeing of the building's occupants. The guideline reference limits applicable in the UK are those published by the International Commission on Non-Ionising Radiation Protection (ICNIRP).

Non-Ionising Radiation Protection

For public exposure, the ICNIRP states that for power frequency (50Hz), magnetic field limits are to be no greater than 100μT. These public exposure reference limits are outlined as UK government policy but are similar across Europe. In addition to this, epidemiological studies have indicated that prolonged exposure to power-frequency magnetic fields above 0.4μT is associated with a small absolute raised risk of leukaemia in children. Although this level is not currently law, it is prudent to consider this finding when designing or specifying a residential building electrical systems.


In Europe and the UK, electronic devices are tested to operate in magnetic fields set out in BS EN 61000-4-8.
Depending upon the environment, an equipment class and test level is given.


Class 1 – 1A/m (1.26μT)
Class 2 – 3A/m (3.78μT)
Class 3 – 10A/m (12.6μT)


This is the maximum level at which the electronic device has been tested and is designed to operate. Higher field levels could affect the electronic equipment and prevent it from operating correctly.

Mag-Stop Shielding

To protect people or electronic devices from the effects of high levels of magnetic fields, shielding is required.


Mag-stop shielding provides an effective solution to reduce power frequency (50/60Hz) magnetic fields to levels less than 0.4μT.

Each project is individually designed and areas of concern are identified. Shielding thickness and required attenuation levels are calculated and all penetrations of the shield are designed and manufactured. Full support through the consultation phases and design stages can be provided by Global EMC.


Mag-stop is available in fully seam welded sheet format to line the surface of the room or as a “pan” type modular system that requires no hot works on-site. Mag-stop is also complemented by Armadillo shielded containment for electrical cable tray or trunking shielding throughout the building.

Transformer Switch Building Shielding - Global EMC

Fast site install compared to welded shields.

No hot works required.

Re-site-able without loss or damage.

Wall finishing can be directly mounted to either side of the "System 8000" shield.

25mm or 50mm deep service voids can be designed in pre-finishing board install.

Can be built into a stud wall (drywall).

Up to 100:1 at 50Hz (-40dB). (based on 1mT field strength).

Up to 1,000:1 at 1~10 kHz (-60dB).

Better than 10,000:1 at 100 kHz+ (-80dB). (based on 1mT field strength).

EEG Labs where 50Hz is a major threat.

Sub-station stray field suppression (50Hz).

LV switchgear room/panel suppression.

Electromagnetic quiet rooms.

NEMP (Nuclear Electro-magnetic Pulse) with MIL-STD188-125 power filters (VLF/ELF/RF/Microwave).

TEM (Electron Microscopy) passive shield rooms for Quasi-DC~1GHz shield.

Shielded Data centres/Shielded Control Centres (VLF/ELF/RF/Microwave).