UCSC Outreach Program -- Tesla Coil Demonstration -- Cool Links

These safety instructions were prepared primarily for staff members, who will be conducting demonstrations at various sites, to access in case they have any questions regarding the operation of the Tesla Coil. You should read these safety instructions as well if you are planning to have a Tesla Coil Demonstration at your facility and ask any questions that may arise regarding the safe operation of the Tesla Coil.

Tesla Coils are potentially dangerous devices and precautions must be taken before every operation to help prevent possible damage to property, injury, or death. Unqualified persons should never be allowed to operate the Tesla Coil. Prior knowledge of high voltage electrical safety is required, and assumed.

Be sure to read ALL of the following guidelines. Be aware that following these guidelines alone is not sufficient to eliminate risk:

1. Verify that the main power switch is in the off position before connecting the power cord to outlet. Never leave the main power switch unattended while the system is in operation. Never leave the system unattended while the power cord is connected to an electrical outlet.

2. Do not attempt to assemble, disassemble, move or come into contact with any part of the Tesla Coil while it is connected to an electrical outlet, even if the main power switch is turned off.

3. Never allow anyone to come into contact with any part of the Tesla Coil besides the main power switch while the Tesla Coil is turned on. Nearly every part of the Tesla Coil is capable of giving a lethal shock while the system is operating, including the power transformer and all associated wiring.

4. When preparing to operate the Tesla Coil, keep in mind that long arcs will be emitted in all directions. Keep the region clear of any objects that may be unintentionally struck by arcs.

5. The operator and all spectators must maintain a distance of at least 10 feet (3 meters) from the Tesla Coil while it is connected to an electrical outlet, even if the main power switch is turned off. All persons must also maintain a distance of at least 5 feet (1.5 meters) away from the power transformer while it is connected to an electrical outlet, even if the main power switch is turned off. Note that under some conditions, the Tesla Coil is capable of producing arcs slightly longer than rated in the specifications.

6. The Tesla Coil must not be operated on the same electrical circuit as any sensitive electronic equipment (such as computers), even if the electrical equipment is turned off. If no separate electrical circuit is available, unplug all other electrical devices that are on the same circuit before operating the Tesla Coil.

7. The power cord is equipped with a three-prong (grounding) plug, and must be connected to a properly grounded circuit. Do not attempt to connect the Tesla Coil to a two-pronged extension cord or electrical outlet. If the ground on the circuit is insufficient, electrical equipment on separate electrical circuits may be damaged, and the operator may receive a minor shock from coming into contact with the metal casing of the main power switch. Do not attempt to run the Tesla Coil on a GFCI (ground fault circuit interrupter) protected circuit.

8. Most electronic equipment will be destroyed if struck by arcs from the Tesla Coil. Many electrical devices can even be damaged by the electricity that is transmitted from a Tesla Coil, without actually being struck by an arc. It is recommended that all sensitive electrical equipment (including pagers, cellular phones, etc.) be kept at least 20 feet (6 meters) away from the Tesla Coil during operation. Under some conditions, some equipment can be affected or damaged at significantly greater distances.

9. Tesla Coils can damage or destroy hearing aids and cardiac pacemakers in the proximity of the unit. This means that Tesla Coils are capable of killing a person wearing a pacemaker. It is imperative to verify that anyone using one of these devices maintains a good distance from an operating Tesla Coil.

10. If arcs from the Tesla Coil strike any devices that are connected to an electrical outlet, or directly strike electrical wiring (including wiring associated with the Tesla Coil itself), then sensitive electronic equipment on the entire circuit may be damaged. Under some circumstances equipment may be at risk on all local electrical circuits.

11. If arcs from a Tesla Coil ever strike telephone wiring or any other wiring, there is risk that equipment may be damaged. It is important to prevent arcs from striking ceilings, walls, and floors where wiring may be present.

12. The arcs from a Tesla Coil generate heat, and therefore pose a small fire hazard. The Tesla Coil may also pose a fire danger if wired improperly, if operated while damaged, if operated for periods exceeding the recommended duty cycle, if ventilation is blocked, or for other reasons. Do not allow arcs to strike fire sprinklers, as they may be triggered.

13. The arcs from the Tesla Coil produce ozone and other gasses, which can build up to toxic levels in unventilated areas. Do not allow this to occur.

14. There are precisely two places on the Tesla Coil that arcing should occur: Out of the toroid, and in the spark gaps, located below the primary coil. The arcs produced in the spark gaps are much brighter than the arcs emitted by the toroid, and may cause eye damage if directly observed for prolonged periods.

15. Under some possible failure conditions, parts of the Tesla Coil may maintain a dangerous electrical charge even after the system has been disconnected from power for several minutes. If wiring is ever disconnected during operation there is an especially high risk of equipment maintaining a charge. If there is reason to suspect that danger is present, do not come in contact with any pieces of the equipment, including wiring, for several minutes.

16. If the Tesla Coil is wired improperly, or is damaged, there may be additional risks involved in operation.

17. There are several extra high-voltage warning labels included with the system. We recommend that these labels be affixed to the Tesla Coil should it be used or stored in a location where persons other than the operator may have access to the unit. We advise that the labels already present on the system not be removed.

18. When not in use for prolonged periods, the Tesla Coil should be partially dismantled to help prevent possible use by unqualified persons. Detach the black and white low voltage wires from the bolts on the two exposed low-voltage terminals on the power transformer. Note that even when disconnected, these wires pose a dangerous shock hazard if the power is switched on.

19. The most dangerous components in the Tesla Coil are all part of the relatively low voltage (10,000-volt) circuitry, including the power transformer, the primary coil, and all wiring in the main unit underneath the primary coil. Arcs can leap several inches from these components. It is imperative to verify that no one can ever come into contact with these components while the main power cord is plugged into an outlet.

To help prevent possible damage to the Tesla Coil, verify the following before every operation:

1. Make sure that the power transformer is placed at least 8 feet (2.5 meters) away from the Tesla Coil so that it is out of range of the arcs. Also, make sure that no wires are raised off the ground high enough for arcs to strike them.

2. Verify that all wiring is connected properly. If the wire at the base of the secondary coil is not connected to the grounding terminal, the Tesla Coil may be destroyed when operated. Make certain that the black power cord coming from the small box at the bottom of the base of the main unit is positioned such that it emerges directly out from the base. If it is coiled back into the base near the chokes, capacitor, or filters, destructive arcing may occur.

3. The Tesla Coil cannot be operated while moisture is present on any part. The secondary coil is shielded with plastic pipe to prevent damage from contact, but it is not airtight (to allow air circulation). Do not run if condensation is present.

4. The electrical outlet used to power the Tesla Coil must not have a faulty ground. The Tesla Coil will be damaged if the electrical circuit is not grounded properly.

5. Be sure that there is no conductive material accidentally placed anywhere on the Tesla Coil. If conductive material is placed too close to the secondary coil, destructive arcing may occur. If using a discharge rod, place the rod above the toroid, not below. Remove excess dust, as some types of dust may conduct enough electricity to damage the Tesla Coil during operation.

6. If arcing ever occurs anywhere on the Tesla Coil other than the spark gaps and the toroid, power down the system immediately.

Do not operate the Tesla Coil if damage is present.