Neon facts

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Clients often ask sign makers the same questions about glass neon: is it safe, does it get hot, what does it cost to run? This guide gives straight answers you can pass on, with the regulations and standards behind them. It was written by Andy Nash, who has made glass neon for over 30 years.

Contents

How is glass neon different from LED lookalikes?

Neon is always glass. LED lookalikes use LEDs in plastic, silicone or acrylic.

A neon tube is bent by hand over a flame by a trained glass bender. An electrode (a glass housing with a metal shell inside) is then welded onto each end. The finished section goes on a bombarder, which pumps it down to a vacuum and passes current through it to heat the glass. Impurities driven off by the heat are pumped out, and the heat also activates the electrode shells. Once it has cooled, the tube is filled with gas, aged in on a transformer to show up any faults, then blocked out: the parts that shouldn't be seen are painted by hand, which gives each letter or shape its definition.

A typical acrylic LED lookalike is cut on a CNC router, has LEDs fitted and soldered in the back, is capped off and has vinyl applied to the sides.

Does neon get very hot to the touch?

Generally, no. A tube runs hot only if there are impurities in it (usually air), the electrodes are carrying too much current because the sign is set up wrongly, or it is installed incorrectly. The one normal exception is an electrode on large diameter tubing run at a high current, around 150mA.

Can neon be at touching height?

Yes, but extra rules apply. Arm's reach is covered in section 7 of the European Standard EN 50107, which deals with protection against contact with live parts. Arm's reach is the zone a person can reach from anywhere they could stand: 1.25m to the front and below, and up to 2.5m above.

When a sign is within arm's reach:

  • If the glass is fully enclosed, for example in an acrylic case, open circuit protection isn't needed.
  • If the glass can be touched, it needs a mechanically protective enclosure to IP2X and open circuit protection. This can be a tray with the connections behind, or silicone caps fixed so a tool is needed to remove them.
  • External metal parts must be earthed, and every electrode connection must be covered by a silicone cap.
  • Full mechanical protection means no opening wider than 12mm in the housing, even if a tube breaks.

Electronic convertors have open circuit protection built in. Other transformers need an internal earth trip setting changed, or a separate external earth trip if the sign is flashed or dimmed.

How long do neon tubes last?

Around 40,000 hours if installed correctly, and switching on and off makes almost no difference.

A pure neon tube can last many years, as long as it stays sealed and unbroken, keeps enough ions to strike and doesn't suffer electrode breakdown. Argon tubes can suffer electrode erosion and have a useful life of over 40,000 hours, though many last much longer. In 2012 the Daily Mail reported neon in a Los Angeles cafeteria that had been left running for 77 years. Phosphor coated tubes do lose some light output over time (lumen depreciation). LEDs do too, and heat affects them more than it affects neon.

Do neon signs explode?

No. Air pressure at sea level is about 1013 millibars. A neon tube is made under vacuum and filled to at most about 25 millibars in small tubes and around 5 millibars in larger ones. A broken tube therefore implodes and draws air in. It is not dramatic and does not throw glass about.

Neon is high voltage. Is that dangerous?

When installed correctly, it is no more dangerous than other household appliances. The high voltage parts are insulated so they can't be touched, and transformers generally have protection that switches them off if a live connection is touched.

Neon counts as high voltage (above 1,000V) but the current is low: usually around 18 to 20mA. A household socket is only 230V but can supply far more current. In an electric shock, current matters much more than voltage. Static electricity, for example, can reach 25,000 to 35,000 volts, but with a tiny, momentary current.

Is the gas in a neon sign poisonous?

No, not in the small amount in a tube. Signs contain neon or argon, both inert gases already present in the air we breathe. Argon tubes also contain a tiny amount of mercury. If a tube breaks, air the room and clear up the glass. The NHS says the small amount of mercury in a lamp is very unlikely to cause health problems, and gives the same clean-up advice as for fluorescent lamps.

Is neon expensive?

Not for a custom, handmade product. Every bend is heated and shaped by hand, a skill that takes years to master. Each section is then fitted with electrodes, bombarded at around 240°C while impurities are pumped out, filled with gas, aged in and blocked out. Given the time, skill and long life of a neon sign, it is good value.

Will a neon sign cause a fire?

Neon is no more likely to cause a fire than any other electrical item, provided it is made and installed correctly with parts built to UK and EU safety standards. If a sign develops a fault, switch it off and have it repaired by a qualified technician before using it again, as you would with any electrical product. Signs imported from outside the UK and EU can be of poor quality and safety.

Can neon be used outside?

Yes. Transformers for outdoor use are IP44 rated and must be mounted correctly. Some small electronic convertors are IP65 and can also go outside, within their voltage limits. The glass itself is perfectly happy in British weather.

When does a neon sign need a fire-fighter's switch?

Fire-fighter's switches are covered by the IET Wiring Regulations, BS 7671. From 15 October 2026 the only current edition is BS 7671:2018+A4:2026. Amendment 4 redrafted regulation 537.4.2 so that fire-fighter's switches are required where the building's fire strategy specifies them, typically for high-voltage outdoor lighting and discharge lighting such as neon.

Earlier editions exempted portable signs and signs of no more than 100W fed from a readily accessible socket-outlet. Do not rely on that exemption without checking the current regulation, the fire strategy for the building and, where needed, the local fire authority.

Where a switch is fitted, the long-standing practice is:

  • separate switches for indoor and outdoor installations
  • for outdoor signs, the switch outside and next to the sign, or a notice next to the sign saying where the switch is
  • for indoor signs, the switch in the main entrance or another place agreed with the fire authority
  • a conspicuous, clearly labelled switch no higher than 2.75m

Some installations instead connect the sign to the fire alarm so it switches off when a fire is detected. Check this is acceptable to the fire authority first.

Fire-fighter's switches exist to protect firefighters spraying water near high voltage equipment. They are not there because neon is more likely to start a fire.

Does neon use a lot of power?

No. Power depends on the size of the sign, the tube diameter and how many sections it is split into. A transformer's starting current is higher than its running current, which drops sharply once the tubes have struck.

To size a transformer, measure the length of tubing, allow for the electrodes in the circuit and choose the current to suit the glass and electrodes. As a rule:

  • the thinner the tube, the less length a transformer can run
  • the thinner the tube, the brighter and more intense the light
  • electrodes are rated for a maximum current, roughly 25mA for 10mm electrode glass, 50mA for 13mm, 80mA for 16mm and 150mA to 250mA for 18mm

Long cable runs also affect power use. Adding capacitors to wire wound transformers can cut their power use by up to 40%.

Try our neon calculator and electrode picker.

Does neon cost a lot to run?

No. Work out the kWh: the real wattage of the transformer divided by 1,000, times the hours it runs, times your electricity price per kWh.

Example: an 8kV 18mA wire wound transformer running at about 95W, on for 10 hours a day, every day of the year:

  • 95W / 1,000 = 0.095kW
  • 0.095kW x 10 hours = 0.95kWh a day
  • 0.95kWh x 365 days = 346.75kWh a year
  • 346.75kWh x 26.32p = about £91 a year

26.32p per kWh is the average Ofgem price cap unit rate for October to December 2026 (direct debit). Business tariffs vary, so use your own rate. As a rough guide, an 8kV transformer runs about 10.2m of 10mm glass or 14.1m of 15mm glass, depending on the number of sections.

How efficient is neon?

Very, and often more so than LED lookalikes. Efficiency (efficacy) is the light given out per watt, in lumens per watt.

Opal acrylic used over LEDs lets through only about 35% of the light. A typical 5050 SMD LED strip in white 6500K with 60 LEDs per metre is rated at around 1,020 lumens per metre. Behind opal acrylic that becomes about 357 lumens per metre, at 14.4W per metre: about 25 lumens per watt.

A 15mm Glostertube 6500K white tube gives about 913 lumens per metre at 50mA and uses about 20W per metre including electrodes: about 46 lumens per watt. Figures vary with the LEDs, the acrylic and the quality of the tube processing, and neon also gives light in all directions.

See our neon glass colour chart for the light output of each stock colour.

Can neon be recycled?

Yes. Neon tubes are recycled in the same way as fluorescent lamps.

Sources

  • BS 7671:2018+A4:2026, Requirements for Electrical Installations (IET Wiring Regulations, 18th Edition)
  • BS 559-1:2023, Interior and exterior signs: design, manufacture and installation of signs (supersedes BS 559:2009)
  • EN 50107, Signs and luminous-discharge-tube installations operating from a no-load rated output voltage exceeding 1kV but not exceeding 10kV
  • Glostertube colour data sheets (light output and power)
  • SIET Neon Handbook
  • The Neon Engineer's Notebook, Morgan Crook and Jacob Fishman
  • Ofgem energy price cap, 1 October to 31 December 2026
  • NHS: can a broken thermometer or light bulb cause mercury poisoning?

Need help choosing transformers, glass or electrodes? Call us on 01892 783 900 or email enquiries@sign-tec.co.uk.