The following is a letter that was printed in "ElectroLink" forum pages 20 & 21, July-August 2001, While I was happy with the improvement the Editor made to my letter, The editor removed my comments that to get the bleeder resistor installed in the jig I had to get help of a Industrial nurse.

Bleeding resistors

Dear Ed
I cannot help thinking that our present Electricity Regulations have gone backwards and no longer actively encourage safety.
   Take Regulation 73 for example. This talks about the risk of electric shock from storage capacitors but doesn't require the fitting of a bleeder resistor. All it says is that they are deemed unsafe if they don't have one and you haven't got a safe working procedure to discharge them before you do the job.
   Regulation 111 (pre-1993) said: "Additional requirements for capacitors ? Every capacitor, unless incorporated for the sole purpose of radio interference suppression, shall be provided with means such as a high-resistance leak for its prompt automatic discharge immediately the supply is disconnected. This requirement shall not apply to small capacitors where no risk of shock can arise."
   This was simple, sensible and safe, but even then it was not always implemented.
   Many years ago, during my apprenticeship, I was factory-servicing television chassis which were wired up to a television jig via dozens of leads. The jig had in it the picture tube, customer control panel, power supply module, and speaker.
   Most times when you turned off the set (jig) the filter capacitor in the power supply would discharge, making the chassis safe to service.
   However some faults left the filter capacitor still charged up at mains rectified voltage. This was over 300 volts and resulted in a bit of a unpleasant shock if you made contact with the live contacts when making repairs.
   The answer from the factory department that made the jig was to suggest using a screwdriver to short the terminals to discharge the capacitor. This resulted in a big flash and a loud bang.
   "Great", you may say, "this keeps all your work colleagues awake." But the trouble was if you had a real hard fault, and those came up frequently, you would be concentrating on the fault and forget to keep your colleagues awake by discharging the cap.
   This give me an idea, why doesn't the department that make the jig put bleeder resistors across the filter capacitor (and comply with Reg 111)? I suggested this, but they said that this would modify the circuit and a fault on the chassis might not be picked up.
   I suggested that they put in a new mains switch in the test jig, with an extra pole to switch the bleeder resistor into the circuit. In the On position the circuit would be the same, but in the Off position the filter capacitor would discharge safely. They would not buy my idea but the problem is still with us today.
   One would think that this regulation would be more important now we have microwave ovens, which can store a charge much greater than 300 volts. Fatalities have already happened overseas.
   Even though most high-voltage capacitors in a microwave have bleeder resistors, there still might be one that sneaks through and let's face it, bleeder resistors do fail.
   While talking to people in the trade I often get the comment, "but all capacitors have a defacto bleeder resistor via load." That is dangerous thinking and confuses a bleeder resistor (that discharges high voltage when there is no load) with the normal discharge when the equipment is switched off.
   My point is this ? the Electricity Regulations used to identify the danger and mandate the solution. Now they get all mealy mouthed and tell us it is unsafe (which we already knew) but don't require the designers or importers to make their product safe in the first instance.
Eric Richards
Auckland

The letter above to the editor shows what is typical of what some "Electronics people" think of electrical safety and coming from the work place makes this example worse, unfortunately this also extends and can be worse with the electrical hobbyist. I do not mind home hobbyist trying to fix home electrical appliances, so long that there is a understanding, "if the home hobbyist can not fix the appliances, bag it all up, and throw it out in the rubbish tin".

In New Zealand, when each electrical appliance has finished been repaired, it required by law to have a earth continuity test done, it must be less that one Ohm from plug earth pin to any other earth point.
Also a high voltage insulation test, it must be greater than one meg Ohms at five hundred volts between mains Earth pin to Phase and Neutral pins.

However there is one appliance that has been exempt "Computer Monitors" The reason, as I understand it from the "Electrical Workers Registration Board". Because technical service information is not always available to repair departments.
This reason must be light entertainment or the most feeble excuse I have heard, Most often now more and more other appliances have to be repaired were service information is not available to most service departments, because they can not become authorized service centers, why should this only apply to computer monitors?

I have frequently tested computer monitors after repairing them, using the two test required by New Zealand law and never had a problem.