Tesla Coils are very Dangerous! You should NOT build or operate one without being aware of the risks.

Electrocution

Mains voltages, 110V or 240V can kill you! Everyday household appliances are built with protection, fuses and earth wires. The control systems for your coil must also be designed and built with fuses and earthing - all exposed metal MUST be earthed and a correctly rated fuse MUST be fitted.

High Voltages present in the NST, tank capacitor, spark gap and primary coil can kill you! Never touch these components when mains power is ON! Even after power is disconnected do NOT touch until you are sure the tank capacitor is fully discharged.

Streamer Strikes!

Direct strikes from a running coil can kill! Watch out for secondary strikes too - a strike to a metal structure will flow internally and may exit the structure at a point near you!

Fire

Be aware of the possibility of Fire. Never run a coil near flamable substances. The output streamers can travel through wood and heat it up to the point of ignition.

Health Risk

Electrical discharges in air cause chemical reactions which produce toxic gasses such as ozone and oxides of carbon and nitrogen. Prolonged exposure to these gasses can cause irritation to the lining of the lungs and to eyes. Never operate your coil in a confined space without suitable ventilation.
Spark gaps produce a lot UV radiation. Never stare at a running gap.


Pacemakers can be affected by the Electromagnetic Field generated around a Tesla Coil. Follow your manufacturer's advice and keep clear.

Noise

Tesla Coils are Very Loud! Wear suitable ear protection.

Accidents

Play safe! Don't operate your coil in cramped conditions. Give yourself and spectators plenty or room. Don't leave cables where you could trip over them.

Caution

Tesla Coils generate an Electromagnetic Field which can induce electrical currents to flow in nearby conductors. Do NOT run your coil in the vicinity of electronic equipment (e.g. computers, camcorders, house wiring etc).

Spark gaps and streamer strikes can cause EMI (ElectroMagnetic Interference) on TV and radio broadcasts. Think about your neighbours - they may complain if their favorite TV show is interfered with!

EMI can flow back through your transformer and control circuits and into the domestic supply. Electrical equipment can be damaged this way so use a mains filter.