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HSE Guidance Notes: Electrical Safety for Entertainers
If you are an entertainer (or work within an entertainment venue) who uses electrical equipment for sound, lighting or other effects, the information on this page is for you. As well as guidance for your safety there are some notes at the end about the law.
In addition to the information on this page (source: HSE), please read the notes on portable appliance testing (PAT) which ensures equipment is electrically safe for use.
CONTENTS
Introduction
Electric shocks can kill
Entertainers have been injured and even killed from electrical shocks while performing or practising. Make sure your next performance is not your last.
Even a very small electric currunt flowing through your body can kill you. One twentieth of an amp (50 milliamps) can cause pain, paralysis of chest muscles and, after a few seconds, upset of heart beat (figure 1).
The higher the current, the more dangerous and quicker are the effects
Risks
An electrical item, for example a cable, may get damaged, exposing bare, live wires.
Apparatus may be wrongly connected so that the outside parts become live.
These are typical examples of how you can get injured. The risk is aggravated because if you are holding an instrumnet or microphone tightly, you may not be able to let go if it becomes electrfied.
If you do happen to touch a live part of your equipment, the current flowing through your body will depend (among other things) on the voltage. Voltages over 50 volts alternating current (or 120 volts direct current) are dangerous even in cool, dry conditions. To be on the safe side live parts over 25 volts AC (or 50 volts DC) should be enclosed all the time to stop anyone touching them.
Even equipment which does not have a mains power supply itself can be dangerous. On some systems audio equipment such as loudspeakers may also be live at dangerous voltages.
Precautions
Inspection, maintenance and repairs should be carried out only by someone who is suitable qualified and experienced such as an electrician.
Do not rely on other people's equipment being in a safe condition or properly connected.
Beware of equipment where separate items may be incompatible or where someone has tried to solve a problem in the wrong way.
Always use a residual current device (RCD) for instrumnets, audio equipment and anything which will be touched or handled while in use. RCDs are relatively inexpensive and widely available from retail outlets selling electrical goods.
Residual current devices
An RCD, also known as an earth leakage circuit breaker, is a gadget which, when fitted to the electricity supply, can detect a very small leakage of current to earth. The RCD will automatically switch off the electricity so quickly that although a person may suffer a minor shock it should have no lasting effect.
It is recommended that the sockets you use, particularly for audio equipment, be protected by RCDs with a nominal tripping current of 30 milliamps (mA). The best place for an RCD is at the main switchboard or at the socket outlet itself. Owners or occupiers of premises should provide this but, if they do not, you can use an RCD fitted plug or RCD adaptor, which is better than nothing.
Remember:
- An RCD is a back-up if something else goes wrong.
- It is important that you always keep your equipment in good coindition.
- If the RCD triups it is a sign that there is dangerous trouble. Check it out and get the fault fixed by someone qualified to do so.
- Never bypass the RCD so that you can carry on using equipment which may be faulty.
Sound Equipment
Earth connections
Lack of maintenance of earth connections causes the commonest electrical safety problem with sound equipment. Any item of equipment which is mains powered should either be double insulated or correctly fitted with a protective earth.
If you are in any doubt about the connections of equipment, consult a competent electrician. Remember that an audio expert might not be an expert in electrical safety.
Single items of equipment, if poorly maintained, usually present very little problem. If a number of items are connected together, however, it is possible that cables screens, together with protective earths, form loops resulting in mains hum on the system.
Do NOT remove protective earth connections. This has been one of the common causes of entertainers receiving electric shocks, some of which have been fatal.
Good quality sound equipment should not cause hum although in some cases you may need to disconnect the screen at one end (only) of interconnecting audio cables. In other cases rearranging the equipment so that the wires do not crisscross the stage can solve the problem. When obtaining new equipment, discuss your needs with the supplier. Some equipment has a facility for disconnecting the 'signal' earth from the safety earth without affecting safety.
Electricity Supply
Sometimes it may be necessary to site a mixing desk at some distance from the power amplifiers, interlinked by multi-core signal cables. Microphones, etc may have their own power supply (not phantom-powered from the mixing desk). It is preferable that all the different parts of the sound system are powered from the same phase of the electricity supply. If not, the phase-to-phase voltages present could increase the risk of fire or electric shock.
Connections
The terminals of amplifiers and the wiring and connections to loudspeakers may carry dangerous voltages. It is essential that wiring with adequate insulation is used, and that any connectors should be safe for use at the appropriate voltage and current.
Extension Leads and Plugs
Extension leads are frequently associated with electrical accidents, sometimes due to incorrect connection. Care should be taken with the connections, particularly if a different plug has to be fitted.
It is absolutely vital that the line, neutral and earth wires are connected correctly. If they are not, the apparatus may work but be rendered lethal, perhaps in a way which would not be detected by a protective device.
If you are not sure how to wire a plug, get someone who is qualified to show you. It could be a matter of life or death (perhaps yours).
If a lead is damaged, it should be taken out of service AT ONCE and replaced, not repaired.
An extension lead should always be fully unwound to avoid the risk of overheating which can lead to fire. Only fully extended leads are capable of carrying the full current capacity of the cable. Do not use multiple adapters as they can easily get overloaded.
Ventilation
High power amplifiers can get very hot and the ventilation around them should not be blocked, for example by stacking other equipment on or near them. Most amplifiers are fitted with thermal protection devices as a precaution against fire but if this protection operates, it will shut the system down. This would not be acceptable during a performance.
Fuses
If your equipment is fitted with 13 amp (square pin) plugs, make sure that the correct fuse is fitted. The rating plate on the equipment or the instruction book will tell you how much electrical power the equipment needs. 3 amp and 5 amp fuses are readily available for these plugs.
Under no circumstances should the fuse be bypassed or replaced by wire, silver paper or a nail. That is very dangerous.
Inspection and testing
However careful you are with your equipment, any apparatus which is moved from place to place is subject to vibration and damage. It is, therefore vital that all electrical apparatus be inspected frequently. As a general guide you should inspect equipment when it is taken out of service for storage or before taking it to a new location. If there is damage to any electrical part or if the equipment causes an RCD to trip, it should be taken out of service at once and repaired by a competent electrician.
In addition, have electrical tests done, preferably by a competent electrician, initially every five times the equipment is used. If you find that this frequency never identifies any damaged or faulty equipment, you could test it less often.
It is a good idea to keep a simple record either on a card or a label stuck to the equipment to show when it was last inspected (date) and tested (date and test readings).
Do not allow repairs to be done by anyone who is not a competent electrician.
110-125 Volt American Equipment
If you have American Equipment designed to work only on supply voltages of 110 to 125 volts, consult a competent electrician. Such equipment must be supplied through a double wound transformer which converts the 240 volt UK electricity supply to the voltage of your equipment. You should not use a single winding auto-transformer.
The use of a double wound transformer to supply American equipment effectively isolates the circuit from any RCD which may be fitted on the supply (mains) side. As voltages over 50 volts AC are regarded as lethal, you should fit a separate RCD (or ground-fault circuit-interruptor in American parlance) to the output side. An RCD is not needed if the transformer is a safety isolating transformer to British Standard 3535 or IEC 742 supplying only Class ll (double-insulated) equipment.
The transformer output(s) should also have overcurrent protection (fuses or, preferable, circuit breakers).
Earthing
Unless the transformer is a safety isolating transformer to British Standard 3535 (or IEC 742), the neutral of the output circuit must be efficiently connected to an effective earth which may be the earthing conductor of the 240 volt mains supply. The earthing conductor should be at least as large as the phase and neutral conductors of the primary circuit. If a 'clean' earth for sound equipment has been specially provided, it should be tested by a specialist electrician before use for electrical protection.
Lamps in series
You should not use two 120 volt lamps in series on a 240 volt supply unless both of the light fittings are designed for 240 volt operation.
Plugs
It is important that you do not use standard 240 volt plugs on lower voltage equipment. Accidentally connecting such equipment to 240 volt mains could be dangerous. If in doubt, check with your electrician which plug you should use.
Lighting
Supports
Unless specifically designed for use at a low level, put lighting rigs out of reach of performers and audience. If cables to lights are run overhead, they should be supported along their length (preferably by an earthed strain wire) unless the cable is of the special type which incorporates its own strain wire. Light fittings should not normally be suspended from a flexible cable alone. They should also have a chain or other support which takes the strain off the cable.
Circuit Separation
If possible you should take the electrical supply for lighting from sockets which are separate from those used for audio equipment.
Residual Current Devices
RCDs may not always be appropriate for lighting circuits. Some types of dimmer control have a relatively high electrical leakage so you could have problems with a number of units fed from one RCD. Other dimmers produce a direct current which can have the effect of 'desensitising' some types of RCD. This is a good reason for making sure that the lighting does not come off the same circuit as the audio equipment which needs reliable RCD protection.
It might be tempting to put an RCD on the secondary side of a dimmer to give additional protection to a lighting rig, particularly where it is positioned at low level. However some RCDs which contain electronic components do not operate satisfactorily at voltages much lower than 240 so the additional protection may be ineffective.
Remember:
- RCDs are recommended for circuits supplying outdoor lighting
- Under no circumstances should you bypass or disable an RCD which is protecting audio equipment
Three-phase Supplies
If lighting is connected to two or three phases of the electrical supply, dimmer cubicles on different phases should be clearly separated to avoid confusion. Only a single phase should be supplied to any one boom.
Connections
If you have lighting on a bar or boom, the connections from the individual lights to the boom should be by plug and socket. For indoor lighting these can be the 'old fashioned' 15 amp or 5 amp three (round) pin types which are often used and quite satisfactory for lighting. High power lights, eg 5 kW follow spots, need correspondingly high power sockets, usually a 32 amp industrial type or the sort used for theatre or location lighting.
The metalwork of individual lights and the bar or boom should be adequately connected to the protective earth conductor.
Always disconnect the supply locally before changing any lamps. The use of plugs and sockets makes this easier as well as providing flexibility for different lighting arrangements.
Cables
Power cables from the lighting booms to the dimmer cabinet or control cubicle are often multi-core. You should ensure that such cables are suitable as regards flexibility and protection against abrasion or other mechanical damage. If there is any risk of the cables getting hot from the lights, they should be of a type which is sheathed in, or protected by, heat-resisting material.
Make sure flexible cables are properly secured in a cable grip at the plug or other termination.
Multi-core power cables should only be connected to one phase of the electricity supply.
All plugs and sockets should be adequate in terms of voltage and current ratings and they should be in good condition; the protective earth connection is particularly important.
Every circuit should have its own line and neutral conductors. If earth connections are looped, you must take care that the wire size is adequate along its whole length.
Earthing
Dimmer control cubicles also provide the marshalling points for cables to the lighting booms. All the exterior metalwork of the cubicles must be adequately earthed. There is sometimes separate provision for the connection of outgoing earth wires for lights. Alternatively reliance is placed on the earth connection of the outgoing plugs and sockets. There should be no provision in control cubicles for 'lifting' (ie disconnecting) earths.
Special Effects
Lasers, strobes and other high intensity lighting may require special arrangements or approval from the local authority, etc before use. Some of these items use high voltages internally and so it is particularly important to ensure they are in good condition and properly earthed if necessary. There may be non-electrical risks such as radiation or epilepsy-induction from such equipment as well. HSE Guidance Note PM 19 (Ref 1) has useful advice on the use of lasers for display purposes.
The Law
Health and Safety at Work Act 1974 (HSW Act)
If you are paid for entertaining, what you are doing probably comes within the scope of the HSW Act (Ref 2). If you are self-employed (even if entertaining is not your main job), you have to look after your own safety and the safety of anyone else who might be affected by what you are doing (section 3 of the Act).
If you are employing other people, you must ensure their safety so far as is reasonably practicable. This includes making sure that the equipment they use is safe and that they are properly informed about possible dangers. You should make sure that they are properly trained and adequately supervised (section2 of the Act).
If you are an employee (even if this is not your main job), you must make sure that what you do does not injure yourself or anyone else. You must also co-operate with your employer on health and safety matters and must not interfere with, or misuse, anything provided for safety purposes (sections 7 and 8 of the Act).
Electricity at Work Regulations 1989
Everybody working on or near equipment using electricity (even if they are self-employed) comes within the scope of these Regulations (Ref 3). Further guidance is given in the memorandum of guidance on the Electricity at Work Regulations 1989 (Ref 4).
Enforcement
The HSW Act is enforced either by the Health and Safety Executive (HSE) or by local authority environmental health officers, depending on what usually goes on at the premises. If you have any doubt about safety matters relating to an entertainment, please contact your local HSE area office or the environmental health department of your local authority.
Almost all places of entertainment also need a licence from the local authority. The law does not say what must be contained in the licence. There will usually be requirements for fire precautions (the fire brigade will be involved) and the licence can include conditions relating to electrical safety. If in doubt, please contact the local authority about the need for a licence and any conditions which may apply. If you have a problem with any of the conditions, do not just ignore them but seek help, either from the authority or through your trade association.
References
- Guidance Note PM 19, Use of lasers for display purposes
HMSO, ISBN 0 11 883370 7
- Health and Safety at Work etc Act 1974
HMSO, ISBN 010 543774 3
- Electricity at Work Regulations 1989, SI 1989 No 635
HMSO, ISBN 0 11 096635 X
- Memorandum of guidance on the Electricity at Work Regulations 1989, HS(R)25
HMSO ISBN 011 883963 2
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