Low Frequency EMF Shielding: What Works for 50 Hz Fields

Low frequency EMF shielding works very differently for the two parts of a 50 Hz field. Electric fields from wiring and cables can be reduced quite easily with conductive materials such as shielding paint or fabric, as long as they're properly grounded. Magnetic fields from appliances, wiring faults and power lines pass straight through those materials, so for magnetic fields the practical answers are distance, switching things off and getting faulty wiring fixed, not shielding.

This guide explains why, what actually blocks each type of field, and how to plan a bedroom that measures low.

What is low frequency EMF?

In the UK, mains electricity alternates at 50 hertz. Anything connected to the mains creates two low-frequency fields:

• Electric fields, which exist whenever a cable is live, even if nothing is switched on. They're measured in volts per metre (V/m).
• Magnetic fields, which only exist when current flows, such as when an appliance is running. They're measured in microtesla (µT) or milligauss (mG).

This is a separate world from radio-frequency (RF) signals like Wi-Fi and 5G. Most products marketed as "EMF shielding", including bed canopies and phone pouches, are designed for RF. That's why it's important to know which field you're dealing with before spending money.

What blocks EMF? It depends on the frequency

• RF (Wi-Fi, mobile, 5G): blocked well by conductive fabrics, foils, metal mesh and shielding paint.
• Low-frequency electric fields: reduced by conductive materials, but only when they're connected to earth. Without grounding, a conductive layer can do little or even pass the field on.
• Low-frequency magnetic fields: barely affected by fabrics, paint or foil. Meaningful reduction needs special high-permeability alloys such as mu-metal, or thick steel, and even then only over a limited area.

How to shield low frequency electric fields

Electric fields are the part you can realistically shield at home. The usual approach is a conductive layer between you and the source, connected to the building's earth.

• Shielding paint on walls: a carbon-based paint such as YSHIELD HSF54 HF and LF Shielding Paint, applied to a wall with wiring behind it, then connected to earth using GSX grounding tape and a grounding plate or point.
• Shielded cables and plugs: in a rewire or new build, an electrician can use shielded cable in bedrooms.
• Simple fixes first: moving the bed away from a wall full of sockets, or unplugging lamps and extension leads by the bed, often lowers electric field readings without any shielding at all.

Grounding must be done safely. Any connection to your home's earth should be checked by a qualified electrician. Our guide to EMF shielding paint covers coverage, primers and grounding in more detail.

Why low frequency magnetic fields are hard to shield

Tester ELF – miernik EMF niskiej częstotliwości ME3030B 16 Hz–2000 Hz

A 50 Hz magnetic field isn't stopped by a thin conductive layer the way radio waves are. To redirect it, you need a material that magnetic field lines prefer to travel through, such as mu-metal, a nickel-iron alloy. Mu-metal is expensive, has to wrap closely around or enclose the source, and loses effectiveness at the edges. That makes it practical for shielding a transformer or a cable run in industry, and rarely practical for a whole room.

The UK Health Security Agency's guidance, updated in May 2026, makes the same point: electric fields "can be shielded easily but it is more difficult to screen magnetic fields with everyday materials." It also warns that devices claiming to reduce fields "may not reduce the fields at all", and recommends no-cost or low-cost steps instead: moving further from appliances in use, spending less time near them, turning them off and moving beds and furniture away from cables. It notes that appliances in use produce some of the highest magnetic fields in the home.

What does reduce magnetic fields?

• Distance: fields from appliances and plugs fall off very quickly. Moving even half a metre away can reduce a reading dramatically.
• Switching off: no current, no magnetic field. Unplug devices that sit near where you sleep or sit for long periods.
• Fixing wiring faults: some homes have higher-than-expected fields throughout because of wiring or earthing faults that create stray currents. An electrician can trace and correct these, which no shielding product can do.
• Rearranging rooms: if a fuse board, meter or heavy-load circuit is on the other side of a bedroom wall, moving the bed to the opposite wall is often the most effective change you can make.

Low frequency EMF blocker for the bedroom: what actually helps

The bedroom is where most people want low readings, because it's where you spend the most hours in one place. A practical plan:

1. Measure first. Use a low-frequency meter that reads both electric and magnetic fields, such as the ME3030B ELF Tester. Take readings at pillow height with the usual appliances on, then off.
2. Clear the bedside. Move chargers, extension leads, clock radios and lamps away from your head, or unplug them overnight.
3. Check the other side of the wall. Fuse boards, meters, fridges and storage heaters next door to the bed are common sources of magnetic fields.
4. Reduce electric fields where needed with grounded shielding paint on the wall behind the bed, installed safely.
5. Re-measure to confirm each change made a difference.

If you're also concerned about RF from Wi-Fi or masts, a bed canopy is the right tool for that, but it won't change 50 Hz magnetic readings. Our EMF bed canopy guide explains what canopies do and how to test one.

Homes near power lines

Homes close to large overhead power lines tend to have higher magnetic fields indoors. Walls and windows don't block them, and whole-house magnetic shielding isn't practical. UKHSA notes that moving bedrooms and living areas further from the line makes the biggest difference within a few metres. Electric fields from overhead lines, by contrast, are largely kept out by the building itself.

If you live near a line, a data-logging meter such as the NFA30M 3D magnetic field analyser can record how readings change across the day and night, since magnetic fields from power lines vary with the electricity load. Your local electricity network operator can also arrange spot measurements.

Frequently asked questions

Can you block low frequency EMF?

Electric fields, yes, with grounded conductive materials. Magnetic fields, not with everyday materials; distance and switching off are far more effective.

Does shielding paint block magnetic fields?

No. Grounded shielding paint reduces RF and low-frequency electric fields, but 50 Hz magnetic fields pass through it.

Does aluminium foil block 50 Hz magnetic fields?

No. Thin foil can reduce RF and, if grounded, electric fields, but it has very little effect on low-frequency magnetic fields.

What is mu-metal used for?

Mu-metal is a nickel-iron alloy used to shield magnetic fields around transformers, cables and sensitive equipment. It's costly and only works close to the source.

Measure, then shield what can be shielded

Tester ELF – miernik EMF niskiej częstotliwości ME3030B 16 Hz–2000 Hz

The most effective low-frequency plan starts with a meter and a notebook, not a shopping list. Find your sources with a low-frequency meter from our EMF detectors range, tackle distance and wiring first, then use grounded shielding for electric fields where readings stay high. Contact our team if you'd like help interpreting your readings.

This guide is general information. Shielding materials and meters reduce or report field levels; they are not medical devices. Any work involving your home's earth or wiring should be carried out by a qualified electrician.