Electrical Safety for musicians on stage
In an ideal world, all of our musical and sound equipment would be regularly serviced and checked for safety by qualified professionals, so that there would be very little possibility of accidents occurring, however, in the real world this is very rarely the case! Musicians do not usually represent the wealthiest sector of the community, and make do with patched-up equipment and amateur repairs, with conventional instruments the outcome of this would be embarrassment, however, when mains electricity is introduced into the equation, the results could be fatal!
I would like to list here a few suggestions and sensible safety precautions that every musician should take on board, so that he or she can enjoy making music, without being at risk of injury or death.
1 - Have ALL of your mains powered equipment professionally tested by a qualified person - this is not an expensive job, and most electricians, and many musical equipment shops are able to perform this test. In the UK, this is called a PAT (Portable Equipment Test) test. After testing (assuming that the equipment passes the test), the electrician will affix a sticker to each item, showing the date of the test. It is a requirement of many larger venues that all equipment used should carry such stickers - mostly, nobody checks on this, but I do know of instances where musicians have not been allowed to use equipment because it did not carry valid stickers!
2 - Make a habit of visually inspecting all mains power cables each time you pack your equipment away, look out for chafed or split insulation, loose cable grips that have allowed the outer insulation to pull out, cracked plugs and any signs of overheating or arcing on the pins.
3 - In the UK (UK mains plugs have an internal fuse fitted) check that each appliance has a suitably rated fuse. This will usually be less than 13A, which is the fuse that usually comes with a replacement 13A fuse - most guitar amplifiers require 5A or less, effects units, mixing desks etc will usually need 2A or 1A. If you are unsure, consult the manufacturer's operating manual.
4 - In the event of a fuse "blowing", always replace it with one of the same rating (make sure you carry spares!). NEVER replace it with a higher rating, or, even worse, wrap aluminium foil around it. The fuse is designed to fail in the event of a fault condition, bypassing this protection may result in an appliance becoming dangerous.
5 - Always carry an RCD (Residual Current Device) circuit breaker, and power all your equipment through it. These are inexpensive devices, and can be obtained from most good DIY stores. These will detect any potentially dangerous current flowing to earth, and will immediately cut off the power quickly enough to prevent injury.
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6 - Invest in some form of Power Socket Tester such as the Buzz-It Check Plug from Martindale Electric. This simple device will check for the presence of an earth connection, and that the Live and Neutral connections are the right way round (another common and potentially dangerous fault). The same company also markets a more elaborate device which tests for other fault conditions, and tests the electrical effectiveness of the earth connection, if you are gigging regularly it is a very good investment! Another worthwhile product is the Stanley range of 6-way power distribution boards from Belkin, which incorporate an earth fault indicator light, and an effective Surge Protector (Very handy if you gig with a laptop or sequencer!).
7 - Periodically open each mains plug and check that all the screws are tight and cable clamps are firm - it is quite uncanny how those little brass screws have a habit of gradually unscrewing themselves! If you are fitting a new mains plug to an appliance, it is a good idea to leave a little bit of "slack" on the earth an neutral wires, but none on the live - this ensures that if the cable grip does become loose, the first connection to be broken will be the live, thus rendering the plug "fail-safe". If you do feel confident about doing this yourself, please ask a competent electrician to do it for you.
8 - Most occurrences of electrocution on stage happen when a person who is playing a guitar with (earthed) steel strings touches a microphone - if there is a fault with either the PA or the guitar amplifier that results in the earth to either the mic or guitar becoming live, the musician will not be aware of it until he or she completes the circuit with disastrous results! If you are in a situation where you may be using someone else's PA (House rig, Hire System etc), I would thoroughly recommend investing in a simple neon "Mains Tester". These usually resemble a small screwdriver, and contain a high value resistor and a neon bulb - just touch the blade to the metal object (microphone, guitar strings etc), while touching the other end with a finger: if there is a dangerous voltage present, the neon bulb will glow.
9 - NEVER remove the mains earth connection from a piece of equipment to cure an "earth loop" there are many effective ways of dealing with earth loops, but this is NOT one of them! Many amps, effects units, mixers etc have a "ground lift" switch which will safely decouple the signal and power earths, alternatively you can try disconnecting the screen from one end of a screened cable connecting two units together. As a last resort, a DI Box that uses a transformer (ie the type that does not use a battery) will pass signal while preventing a ground current from flowing. The mains earth connection is there for your protection - never remove it!
10 - If you are performing at an outdoor event that is supplied by a generator, sneak a peek at the generator to ensure that it has been properly grounded by an earthing rod or some similar scheme (This usually consists of a heavy metal stake hammered into the ground, connected to the generator by a thick wire). If the generator is not properly grounded, there may be a potential difference of several hundred volts between the generator's "ground" and the muddy patch that you are performing on! This is a fault that will not be shown by an outlet tester, however, the afore-mentioned neon "Mains Tester" will detect this fault condition.
11 - Always allow yourself plenty of time to set up before a show, not only will you probably perform better as a result, it will also give you a chance to check out any potential safety risks that may be present at the venue.
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