Workplace Disasters are Waiting to Happen
These examples here are from actual workplace situations and our personal experience.A large Melbourne metropolitan machinery manufacturer had a WorkSafe audit. They were told to get their act together as far as testing and tagging was concerned.
During the testing and tagging phase, 80% of their workshop equipment failed. The company insisted that they had 'their electrician' to do the repairs. So that he did, and even some of his repairs were failed as below standard - wired up a three phase extension lead and reversed two phase and using 3 core flex to repair double insulated appliances.
Most of the extension leads failed because the last 4-5 metres from the socket were peppered with welding burns. This occurred due to poor work practices and lead management.
Manager kept on saying "I'm an electrical engineer " and claimed he knew what he was doing.
No! We are Not Kidding!
At a large Secondary College - Can you imagine an extension lead with two male plugs - one at each end? Well this college had a photographic enlarger timer with two three pin plugs instead of a plug and socket.
There was a three pin plug on one end and a recessed caravan inlet on the other (virtually a 3 pin plug on each end). - This meant the enlarger could no longer connect to the timer so they swapped the enlarger plug for a 3 pin extension cord socket. We are not kidding. This was one of the most dangerous manoeuvres ever.
At the same college, a number of enlargers timers had been previously tested
and tagged. This had been done by an electrical inspector, the person who keeps
your electrician honest and makes sure that the work meets the required
standards. The timers were wired incorrectly with active and neutral
transposed. So what? They had a pass tag attached and it should have been
a FAIL as the device is potentially unsafe.
Commercial Cleaning Equipment
This area is fraught with problems. AS3760:2003 extended the retest time for Class I
(earthed) appliances and cord sets
used in commercial cleaning from six to
twelve months. We believe this change is unrealistic as this equipment
suffers more abuse than equipment in a manufacturing area. The flexible leads
are usually light duty to aid manoeuvrability making them more susceptible to
physical damage. Our experience shows most problems occur because of lack of care and poor lead handling.
Poor lead handling often has problems in rewinding leads fixed on appliances
like vacuum cleaners. The problems start when the operators continually rewind
the lead from the plug end, each time adding to the twist in the flex.
Eventually, the flex become unmanageable. ... Light weight
vacuum cleaner cord sets, poorly handled are very prone to penetrations and deep
elongated cuts. Poor lead handling prevents the cords from laying flat. Many Industrial buffs and scrubbers have damaged flexes because the operators buff through the leads and ignore the problem.
A company had two portable electric blowers specially made up for them - in
galvanised sheet metal cases on wheels. The electrical wiring was done by a Registered Electrical
Contractor /Switchboard Manufacturer who also does Testing and-Tagging. The client picked up the blowers and took them to a Construction Site where
we were requested to Test and Tag. Imagine the horror - here was a Class I Earthed piece of equipment with no earth connected to the metal frame. The item was quickly returned to the manufacturer for rectification.
Recently tested and failed a Bain Marie that had been stored outside. The item did not look good visually - it had a heavily scaled and possibly corroded heating element and thermostat capillary tube, a dodgy switch and it had evidence of water in the plug. The earthing was satisfactory; however the Insulation Resistance was well below the minimum 10,000 ohms. The owner was a little upset because the unit was working when they used it 2 weeks ago. Thankfully he also recognized that it was potentially an electrocution hazard under an adverse set of circumstances (like being plugged into an outlet or extension lead with a poor or no earth connection.
There are many owners who cut corners for safety!
A fridge in a retail outlet had a home repair carried out on it - the flex had been re-terminated and twisted around the terminals and tightened down. What they didn't realize that they had used a spare terminal to connect the earth wire and the fridge frame was not connected to that terminal - All that needed to happen was a fault develop in the fridge and have an innocent person touch the fridge and an earthed object - Funeral Service.
Another retail outlet had a extension lead passing under a multi-door fridge with a condensate tray that was prone to overflow - the lead had multiple flex penetrations, a melted section and poor connections to the plug. Another fridge in the same location had a lead the outer sheaf removed for 200mm and a break in the active wire that had been twisted together and covered with a small inadequate piece of insulation tape. Why do people take such risks and create "A disaster waiting to happen"?
Would you use this guy?
The electrical industry is prone to incidents when people take chances with improper practices. A story in a local paper featuring an electrician promoting his business left us shaking our head. The article made the electrician appear boastful of the electric shocks that he had received over time. The accompanying head shot revealed a scruffy looking guy, with a family name that implied scruffy and the whole article left us shaking our heads - This guy was ... a liability to himself, his family and his customers.
The only way an electrician can get an electric shock at work is by cutting corners with safety.
How comfortable would you feel having this person being responsible for your electrical safety?
Notebook Computer Chargers
This is a tragic story of loss. There had been a large rollout of new IT equipment and it involved over 100 notebook computers. Our role was to test and tag the AC Adaptors or Power Supplies. One version was failing too often with intermittent earth continuity and we raised this problem with Energy Safe Victoria. They took it up with the manufacturer. The failure rate was over 20 percent.
The tragedy is that one newly married manager took the computer home and went out leaving it on. They returned later to discover the home had been completely engulfed by fire, their beloved pet dog was dead, their wedding gifts gone, their photos gone - in fact they had lost everything except each other. The fire investigator identified the fire source as the notebook computer power supply. There was no safety recall because the investigator was unable to identify the brand and model details.
Warning - do no leave electrical equipment running unattended ever!
Home Made Extension Lead
What's the risk of using an untested homemade extension lead in a workplace?
How much damage can a home made/repaired extension lead cause?
Well, it depends on who made it - and when it was made.
The problems all started when a pilot briefing officer wanted to moved the serially connected laser printer closer to a desk without letting technical staff know. This was the first mistake. The power cord was too short and so they brought in one from home. This was the second mistake. The third mistake was not having it checked by a competent person prior to using it.
So what happened?
Three pieces of equipment were destroyed.
The earth connection in the plug came off and touched the active pin. This fed 240 volts down the extension lead earth wire and onto the frame of the now unearthed laser printer. The voltage looks for the path of least opposition and fed through the printer's data interface and through the data cables to two other buildings into the computer serial port and also to the satellite earth station terminal. All three items were destroyed at a parts cost of approximately $5000 for what could have been avoided by purchasing a new cable for less than ten dollars.
AA satellite hut - PC and the Satellite Earth station receiver all damaged and all because of a faulty lead feeding mains voltage into data cabling across three buildings leaving a trail of damage.
Workshop Pedestal drill.
How essential is it to test after doing modifications and repairs?
Absolutely Imperative is the answer. It's an unfortunate fact of life that the primary reason for an earth connection is to protect the electrical installation by blowing the fuse or tripping the circuit breaker on the switchboard. But what happens when the earth is disconnected off the foot control. Well, it then puts people at greater risk if or when that metal component becomes live. Now is the time when someone accidentally touching a live metal part can be electrocuted. So what was the issue? An electrician modified a pedestal drill to incorporate a Halogen work light - a great innovation for improved safety. However, the equipment was not tested and tagged prior to being returned to service. This would have revealed the fault without potentially placing users at risk if another fault later developed in the drill.
Remember, it is not always the single instance that creates the hazardous situation, it is often the coincidence of two or more things that escalate to a hazardous event such as electrocution.